Archive for the Solar Category

Do I Need Batteries For My Solar Panel System?

Do I Need Batteries For My Solar Panel System?

Do I Need Batteries For My Solar Panel System

NAVIGATION

Imagine you’re in the middle of the biggest storm of the season and your whole neighborhood has lost power. Luckily, you’re still able to watch TV, heat up your dinner, and check in online, all thanks to your solar battery bank.

Whether or not you need batteries for your solar panel system is an extremely common question, especially for folks who are just getting started with solar. But this is a simple question with a complicated answer, so I wanted to share some of what I’ve learned.

ryans tiny house

Hi, I’m Ryan

Living off the grid with solar has been my life for the last decade. I’ve learned a lot about this way of living and batteries are at the core of making that happen. Here’s what I’ve learned.

ryan mitchell simple living expert

Do I Need Batteries For My Solar Panel System?

Do I Need Batteries For My Solar Panel System

Not all solar panel systems need a battery backup to work effectively, so how do you decipher if you need one? There are so many benefits to using a solar power battery bank, like grid independence, energy security, and lower electricity bills. However, this doesn’t mean batteries are required to go solar.

In my opinion, battery backups are the way to go. A solar battery bank can help you avoid pulling expensive electricity from the grid when your solar panel system isn’t generating enough power to meet your needs, which helps offset the initial cost of batteries, particularly if you have variable power rates with your energy provider.

Solar battery backups will likely reduce your carbon footprint, reduce your electricity bill, and help you gain energy security should the grid short circuit.

best solar panel system for my house

Are Solar Batteries Worth It?

Are Solar Batteries Worth It

Just because battery backups are great for me doesn’t mean they’re great for everyone. In order to decide if you need batteries for your solar panel systems, it is important to understand what battery backups actually do.

As a general rule of thumb, experts say that home batteries are financially “worth it” when any two or more of these conditions are met

  • You experience power outages
  • Your peak and off-peak utility power rates differ
  • You qualify for cash incentives for installing a battery
  • You are installing batteries alongside a home solar system
solar panels on a house roof

When it comes down to the numbers, you often have to make a decision about batteries based on financial realities. In some cases, the return on investment (ROI) is short and then you’re saving money every month after recouping your initial investment.

tiny-house-solar-panel-setupThe power company wanted to charge me $15,000 to run a power line to my home. Instead, I spent that same money on a solar array and batteries, which was an instant ROI, and I haven’t had a power bill since. Crunching the numbers, that’s $25,000 I didn’t have in power bills since I went solar!

In other cases, you might realize that instead of batteries, you could just buy more panels and sell the excess power back to the power company. Then you can use those credits when batteries would normally help, using “the grid” as a quasi-storage system.

For me, being off the grid, batteries were required since I didn’t have a grid to pull from. But even if I were grid tied, batteries would be a cost I’d shoulder because it makes life much more comfortable.

tiny house solar

Do Solar Panels Work During A Power Outage?

Do Solar Panels Work During A Power Outage

I can’t tell you the number of times that I’ve gotten a call from one of my neighbors asking if they could come charge their phones because the power had been out for a while and I had no idea! My air conditioning would be running, I was watching a movie and cooking dinner like nothing had happened.

The magic of the battery backup is that your power can be accessed even when the grid fails. When your home doesn’t need all the energy being produced by your panels, the excess energy is automatically stored in the battery bank to be tapped into at any time.

power outageIf your panels are connected to your local utility grid and it goes out, they are designed to stop funneling power so that the power doesn’t feed back into the grid. When the grid fails due to a natural disaster, overload, or maintenance work, your panels will stop producing energy in order to protect utility workers fixing the lines.

There are only two ways to continue to get power from your solar panels during a grid outage: using a battery or using an inverter with battery capacity. The only inverter type I know of with the capability to keep your lights on during an outage is the Enphase IQ8s.

When you add a solar battery backup to your solar PV system, you will still be able to access electricity in your home even when your neighborhood is suffering from a power outage. This is because the battery backups literally store energy for your home to access, independent of your city’s main grid.

10 reasons to live off-grid

How Do Solar Panels With Battery Storage Work?

How Do Solar Panels With Battery Storage Work

If solar battery banks are so magical, how do they actually work? A battery system regulates the flow of electricity during an outage, allowing your solar array to stay powered, and by storing excess energy when more is being generated than the demands of the home.

Your solar panels take in the solar energy from the sun and convert it to DC power. That DC power then flows to the charge controller, which regulates how much power is stored in your battery backups and how much goes to your inverter.

Your charge controller saves your battery backups from overcharging or over discharging electricity. When the energy is discharged, it goes to your inverter. Then, your inverter converts the DC power to AC power, which your house is able to use. This is the flow of power for systems with DC coupled batteries.

However, some systems are AC coupled or have their own inverter solution, in which case the DC power moves from your panels into a solar inverter, then a battery inverter, and then straight into your battery bank. From there, the power flows through another battery inverter, and is then discharged as useable energy in your home.

solar panel system parts list

Whether or not the battery bank is installed in the circuit before or after the inversion to AC is dependent on the type of battery and inverter that you use. Both setups certainly have their own pros and cons.

Is Solar Power Battery Backup Right For Me?

Is Solar Power Battery Backup Right For Me

One thing I wish I knew before going solar is that the decision to do so is actually made up of many smaller decisions. There’s the decision of going on or off grid, backing up with batteries or a generator, type of inverter, charge controller, and batteries you’ll use, how many batteries to buy, and much more.

I’ve ground mounted 15 panels on my property that are backed up with flooded lead acid batteries, but I didn’t come to that decision overnight. I did a ton of research to understand what method would be best for me.

These decisions are often navigated more easily with the help of a local solar provider. They understand a lot of these details, are familiar with your local codes, and can help you make the right decisions.

best solar panel system batteries

Grid Tied Solar Vs Off-Grid Solar

Grid Tied Solar Vs Off-Grid Solar

It’s a common misconception that using solar panels means you’ve gone off grid. In actuality, you can use solar panels both on and off the utility grid.

With the off-grid method, battery banks are required to store solar energy. However, batteries are still an option with the grid-tied method if you want to reduce your dependency on the grid without disconnecting fully.

solar panel off grid setupThe primary difference between grid-tied solar and off-grid solar is where your solar panels store their energy. With the grid-tied method, the energy your solar panels create is fed into the utility grid and is used to generate electricity for homes in your area.

In return for feeding your solar energy into the main grid, you’ll receive credit that you can access anytime. This is how you “store” energy to use when your panels are no longer getting sun in the middle or the night or on an especially cloudy day.

The main setback with grid-tied solar panels is that you’ll be affected by power outages. If the main grid goes down, your grid-tied system will shut off in order to prevent energy from feeding into the system and potentially harming utility workers. However, many folks find this easier than having to invest in and keep track of battery backups.

The more common method for storing solar energy is going entirely off grid, but make sure you’re ready to take this leap before deciding to disconnect. In some cases, you may be required to remain on the grid by local authorities.

With off-grid solar, you aren’t using grid connection to store extra energy, so backup batteries are required. The main reasons I see friends lean toward the off-grid route are avoiding power outages, lowering electricity prices, and having less involvement from code enforcement. For me, the off-grid method was really the only way to go because of where my house was located.

Backup Generators Vs Solar Battery Backup

Backup Generators Vs Solar Battery Backup

Another core decision when installing solar is what method you want to use to back up your home electricity for those moments when your main system fails. Backup methods are highly recommended to produce greater energy independence and generally be prepared for power outages or solar panel failure.

There are two main ways that people tend to back up their electricity: a whole-home generator and a solar battery backup system. I used a portable backup generator for the first two years I used solar panels. Later I opted to upgrade my system because portable generators require more maintenance that I cared for.

solar panel batteries pro tip

“We recommend battery backups over a generator. Battery will instantaneously kick on and supply the critical loads for the home. Gas or oil burning generators often take some time to turn on.”

– Matt C., EnergyPal

Backup generators provide electricity by burning a fossil fuel like natural gas or propane. Some backup generators turn on automatically when an outage is detected, while others are turned on manually. Some higher end inverters will have an automatic start for generators when your batteries get below a certain threshold.

Depending on your setup and budget, it can go either way. I honestly prefer the solar battery backup method over a backup generator, but a combination of the two is even better.

Benefits Of A Backup Generator

  • Backup power on demand
  • Can utilize existing gas line
  • Low installation costs
  • Can be added to any home

Disadvantages Of A Generator

  • Noise
  • Will incur gas costs
  • Maintenance
  • Burns fossil fuels

The solar battery backup method is totally different and is what I tend to recommend for those going solar. Batteries will store and disperse the renewable electricity generated by your solar panels.

Solar battery storage makes sure that your house uses as much of the renewable electricity coming from your solar panels as it needs. They can be used when your panels have low solar output, like at night or on an especially cloudy day.

Pros Of Solar Battery Backup

  • Low maintenance
  • Detects power outages
  • Decreases your carbon footprint
  • Qualifies for solar tax credit
  • Quiet operation

Cons Of Solar Battery Backup

  • Higher cost
  • Less predictable
  • Battery lifespan ends
  • Installation costs
  • Poorer charge retention

Choosing The Right Inverter To Work With Battery Backups

How To Choose The Right Inverter To Work With Battery Backups

Whether you choose to go on or off grid with your solar system, it is vital that you have a high-quality inverter. Your inverter is the apparatus that’s in charge of creating power that you can actually use in your house. It does this by transferring the high voltage DC power from your panels into AC power that is safe and useable in your home.

So, how do you make sure you’ve chosen the best inverter for your panels?

Inverters come in size ratings, measured in watts. As a very basic rule of thumb, you want your inverter to roughly match your solar panel wattage. This means if you have a 2000-watt solar panel system, you’ll need at least a 2000-watt inverter to successfully convert your DC power to AC power.

It’s also a good idea to give yourself some wiggle room incase you want to add some more panels later. If you’re choosing a good quality inverter from any of the name brands, you’re going to have a “smart” inverter, meaning it will be able to dynamically adjust as needed up to a certain level.

Inverters typically have a typical load rating that it can handle constantly and then a spike/peak rating that can handle higher wattage for short periods if there are any surges.

simple electrical for tiny houses

Once you know the wattage needed for your inverter, you can look into which type of inverter to invest in. Inverters for solar panel systems can be broken down into three basic types. A string or single inverter will need enough wattage to cover all of your panels, while a microinverter system only needs enough wattage for the panel it’s connected with.

Inverter Types:

  • Micro-inverters (Grid tied)
  • String inverters (Grid tied)
  • Hybrid inverters (Off grid)

What Are Microinverters?

What Are Microinverters

A microinverter is, as can be inferred from the title, the smallest kind of inverter. A microinverter is about the size of a DVD player and can handle energy conversion of one to two solar panels (about 120/230V, 60Hz of AC power).

They’re called microinverters due to the fact that the conversion from DC to AC power is done by several small inverters as opposed to one large inverter handling the entire load. There are many advantages to choosing this route as your solar inverter of choice.

solar panel systems pro tip

“We recommend microinverters, as they allow maximum energy production during the times of partial shade, have great warranties, and are proven in the residential space.”

– Matt C., EnergyPal

Microinverters have many advantages in any size home. For one, micro-inverters are easily grid-tied, so you don’t have to disconnect from the grid to use them.

Another plus is that if one inverter in your micro-inverter fails, it will not disrupt your entire system and will continue to power your home, which would not be the case with a string inverter.

What Are String Inverters Or Central Inverters?

What Are String Inverters Or Central Inverters

Grid-tied string inverters, also called central inverters, are the most popular type of inverter for a solar panel system. Many folks like this inverter type because of the way it streamlines clean AC power straight to the electricity grid.

Additionally, grid-tied string inverters allow self-consumption of your solar electricity in your panels. They’re about the size of a bread box and are mounted to your wall. String inverters are also connected to the utility grid and to the house power circuit, so you don’t have to go off grid if you don’t want to.

Another reason many people like this option is the price. String inverters tend to be the most affordable option when you take all elements into consideration. Smaller solar panel systems may find a more expensive microinverter to be worth the increase in price, but for medium-sized or larger homes, a string inverter is the way to go.

While string inverters are good for many applications, I still often suggest people make the leap to the third type of inverter.

What Are Hybrid Inverters?

What Are Hybrid Inverters

The third type of inverter is the hybrid inverter, which is the type I use (Schneider SW 4024 Inverter). Hybrids are strategically designed to deliver AC power off the grid and protect your home from electricity loss or power outages. Hybrid inverters always require a battery for electricity storage, as it doesn’t store any power in the utility grid.

solar power battery managementHybrid inverters are the most intelligent type of inverter out there, because they’re designed with the ability to regulate the charge and discharge current of the battery on its own. Just like with a grid-tied inverter, hybrids take DC electricity from your solar panels and convert it to AC power.

However, hybrid inverters go a step farther. They have their own magic touch, as they’re able to feed DC power into the battery during charging.

This means that if your panels are not getting enough energy from the sun, the inverter picks up on that and automatically pulls extra DC electricity from the battery, converting it into AC power your house can use.
Many of these inverters also have the ability to start up a whole house generator when your batteries get too low. They can handle a wide range of setups and, in my opinion, are worth the investment.

It’s important to note that you can’t just swap a string inverter with a hybrid inverter, as they require different wiring. However, if you can swing the extra cost, hybrid inverters can end up being worth your while. They provide power backups when the electricity grid fails and solve issues stemming from renewable energy variability.

Does Solar With Battery Storage Use Charge Controllers?

Do Solar Panels With Battery Storage Use Charge Controllers

When I first made the decision to go solar in my own tiny house, I was confused as to whether or not I actually needed a charge controller. Not all panel systems need them.

soalr panel charge controllerThe distinction is this: If you have batteries, you’ll need to have one because a charge controller manages them.
I liken a charge controller to an amusement park ride operator for your solar panel system. A ride operator regulates how many people can board the ride before it reaches max capacity. Similarly, a charge controller regulates how much energy can be safely stored in your battery backups and how much can be fed to your home through an inverter.

If you aren’t relying on battery backups, a charge controller isn’t necessary. They’re best used with battery backups such as for van life or a small, off-grid tiny home.

Choosing The Right Charge Controller For Solar Panel Batteries

Choosing The Right Charge Controller For Solar Panel Batteries

If you are using a solar power battery bank for home, you’ll want to choose a charge controller that can give your batteries as long a life as possible by preventing them from overcharging or discharging too much power.

There are two types of charge controllers:

  • Pulse width modulation (PWM)
  • Maximum power point tracking (MPPT)

The PWM is an older style and costs less, but it’s not as efficient the MPPT. MPPT charge controllers are the most common these days and can gain you up to 30% more power than the PWM controllers, so I would recommend going with the MPPT.

At the end of the day, both will work fine with your solar panel batteries, but the MPPT is worth the investment. Once you decide between the PWM and the MPPT, you’ll need to figure out the amperage needed for your charge controller.

Calculate Amperage With:

  • The wattage of the solar array
  • The battery bank voltage

Use this formula to calculate the amperage

Watts / Volts = Amps

Take the total watts of the solar array divided by the voltage of the battery bank. This will give you the output current of the charge controller that you need.

pro tip for solar batteries

“Always make sure you have a charge controller that is large enough to handle the amount of power and current produced by your panels.”

– Matt C., EnergyPal

If you don’t feel comfortable doing this on your own, you can typically find a sizing tool on the manufacturing website to make sure you’re on the right track. You can also call the company if you don’t see the info online or want to speak to a real person.

After you figure the type and size you’ll need, it just comes down to brand. There are so many makes and models of charge controllers out there.

I use the Schneider MPPT 60 Charge Controller for my panels. I found it to be super easy to install and it was part of the same product line as my inverter so it just .worked out of the box without any fuss. However, there are a ton of great brands out there that can give you the results you’re seeking.

How Much Do Solar Batteries Cost?

How Much Do Solar Batteries Cost

Your solar battery cost is going to depend on which type of batteries you choose, how many you buy, and what it costs to install the type you roll with.

solar panel system pro tip

“Government incentives, special battery program rebates, and additional savings from rate arbitrage allow the solar battery to quickly pay for itself.”

– Matt C., EnergyPal

The average cost of solar batteries ranges from about $5,000 to $7,000, not including installation costs. However, don’t just consider the upfront costs when deciding if you want battery backups.

Consider the gross price, the price per relative capacity, the installation costs, the cost for any additional equipment, and the longevity of the battery when factoring the overall solar battery cost.

How Many Solar Batteries Are Needed To Power A House?

How Many Solar Batteries Are Needed To Power A House

Understanding how many batteries you’ll need to power your home will also factor into your solar battery cost. The number you’ll need will depend on the size of your home and your specific electricity needs. One battery usually won’t cut it — you’re going to need a whole series of them in most cases.

batteries for solar powered houseThe number of batteries comes down to what you want to power when the power is out. Anything that deals with heating and cooling, or cooking are going to be very intensive power loads. Practically speaking I’d suggest not trying to power them from batteries, but have an on-demand generator.

Your fridge, freezer, ceiling fans and lights (if they’re LED), modern TVs, and mobile electronics (phone, laptops, tablets) will be a moderate load and can reasonably be powered with a larger battery set. This setup is a really practical approach to battery backs because it keeps your food cold, a fan going and entertainment and communications ups when the power goes out.

If you want to go off-grid completely and rely on your batteries as your main energy source, I would say you’ll need anywhere from eight to 15 batteries. As an off-grider who lives in a tiny house, my system uses 12 batteries as my main source of energy and I have been satisfied with that.

How Long Do Solar Panel Batteries Last?

How Long Do Solar Panel Batteries Last

Generally, solar batteries last anywhere between five and 15 years. However, different battery types are going to have different lifespans.

Lithium-ion batteries will last the longest, typically 10 or more years. Flooded lead acid batteries can have a lifespan anywhere from three years all the way up to 12 years, depending on the manufacturing process. AGM batteries have the shortest lifespan at about three to five years.

best solar panel sytem for my house

Solar Battery Types: Choosing The Best Solar Battery

Choosing The Best Solar Battery Type

Once you decide to back up your solar panels with batteries, next up is determining which type of batteries to use. There are advantages and disadvantages to each type, but these are the basics I believe you should know about each type when trying to make your choice.

Lithium-ion Batteries

Lithium-ion Batteries

Lithium-ion batteries are typically used in laptops and cellphones, but they’ve been used more and more lately as solar power battery banks. Lithium-ion batteries are one of the more expensive kinds out there, but the advantages tend to justify the higher price tag, particularly as their prices come down.

The drawback with using lithium-ion batteries is that they require a special charging process which will need to be followed exactly if you are using a solar panel to charge it. On the other hand, lithium batteries can handle deeper discharges, so you need less overall capacity than you would with a comparable lead-acid battery bank.

The biggest draw for me is that they are a sealed battery, so you don’t have to worry about topping off with water like I do with my lead acid batteries.

Lithium Battery Advantages

  • Longer lifespan
  • Faster charge
  • No maintenance
  • Efficient power usage
  • Deeper discharges
  • No off-gassing/ventilation
lithium ion battery for solar panel systems
solar panel power battery pro tip

“We recommend Lithium-ion batteries for home storage. There are a couple different lithium-ion chemistries, but the chemistry that has emerged as the best mix of price, reliability, safety and ability to cycle is lithium iron phosphate.”

– Matt C., EnergyPal

Flooded Lead Acid Batteries

Flooded Lead Acid Batteries

Flooded Lead Acid batteries (FLA) are the most common batteries used for off-grid solar setups. These batteries are designed to handle daily charge cycling and work well for folks who like to be hands on with their system.

Back when I bought my batteries, lead acid batteries were the way to go with solar panels. At that time, lithium-ion was very expensive, so lead acid was the only reasonable option. I use twelve Trojan L-16 6v 370 AH Flooded Lead Acid Batteries in my setup.

They do require a little bit of extra maintenance, but for me, the low price and high efficiency is worth the extra work. I tend to like being hands on with my house maintenance because I know I can do it and like to have that autonomy, but if that’s not you, some of the other options may be the better move.

Lead Acid Battery Advantages

  • Most affordable
  • Recyclable
  • Easy to dispose of
  • Highly reliable
  • Prevents overcharging
Flooded Lead Acid Batteries

One main thing to note with flooded lead is that the plates of every cell in the battery must be submerged in water in order to keep working (this is where the “flooded” part of the name comes from).

You’ll need to add water at least every three or so months to keep the plates submerged, but I would recommend checking on them once a month to make sure they are doing their thing.

AGM Batteries

AGM Batteries

AGM stands for absorbent glass mat batteries. The glass mat technology is what allows this type of battery to be spill proof. The biggest difference between AGM batteries and standard lead acid batteries is the level of maintenance they require.

AGM batteries are completely sealed, and you’ll never have to check water levels or deal with expelled gas like you do if you choose to use the lead acid route. AGM is a great option is you don’t want to spend a ton of money and also don’t want to constantly check in on your panel system.

AGM Battery Advantages

  • Inexpensive
  • Light weight
  • Spill proof
  • Non hazardous
  • Self-contained
  • Handles temperature changes
agm battery for solar

Tesla Power Wall

Tesla Power Wall

The Tesla Power Wall is kind of in its own category when it comes to solar battery backups. It’s not just a battery, but an integrated battery system that stores your solar energy and protects your power when the grid goes down, as any battery backup can do.

It’s an extremely popular choice because the system is so intricate and tends to be fail proof. There are many reasons people love this battery brand; it’s all the rage in the modern solar energy world.

One of the main reasons people choose to go the Powerwall route is that it has one of the highest efficiencies and reliability as far as solar battery systems go. The major downside? It’s expensive.

Users argue whether or not the Powerwall is worth the investment in the long run. When you break it down, you’ll net $358 in annual savings and pay off the Powerwall in 31 years. This means it would likely take four times the warranty period for the Powerwall to actually pay itself off.

For some, the high quality is worth the expense. For me, I went with a more affordable option that still gave me good battery life, charge, and efficiency for my solar panel system.

Tesla Power Wall Advantages

  • Saves money over time
  • Increases panel efficiency
  • Supports larger loads of power
  • High efficiency
Tesla Power Wall

Another drawback with Tesla is that there are often long wait times with the supply chain, and it’s not yet available in every area. If you’re in no hurry, this isn’t a concern, but if you’re trying to get your system ready fast, you may want to go another route.

Check out these brands if you’re looking for a similar integrated battery system, but don’t want to wait as long as you would for Tesla’s installation:


Your Turn!

  • Do you want battery storage for your solar panel system?
  • How many batteries will you need in your solar battery backup?

Solar Panels For Tiny Houses: How I Went Off Grid With My Tiny House With Solar Power

Solar Panels For Tiny Houses: How I Went Off Grid With My Tiny House With Solar Power

solar power for tiny houses

It’s hard to imagine that I’ve been powering my tiny house off solar panels for my tiny house for over 7 years now! Not having a power bill for almost a decade has been incredible. With that in mind, I wanted to get some real-world experience with my system to give you all the full picture of what it’s really like to power your tiny house with solar: how many panels, how much does it cost, and more.

Solar Panels For A Tiny House

choosing solar panels for a tiny house

Many people have asked me about putting solar panels on a tiny house because I’m one of the few out there that is totally off the grid in my tiny house. I’ve had to figure things out like how to run my air conditioning off solar, how to cook with solar in a solar oven, and how I use solar generators as backup power in a pinch.

Tiny houses are a great candidate for solar power because the smaller space makes for low power needs. While the traditional home in America uses around 30 KWs per day, my tiny house uses around 3 KWs per day.

Every decision I made during my tiny house build, from choosing LEDs lights, to a super-efficient minisplit system, and an on demand hot water heater all were chosen to reduce my power consumption. Since I built my own house, these decisions were pretty simple and, in the end, didn’t cost me much more. Any additional costs for things like a high SEER rating HVAC system quickly paid for themselves by letting me have a smaller solar panel array and batteries.

How Much Power Does A Tiny House Use?

A tiny house will use around 4 KWs per day. Typically, around 80% of that power will be used for heating and cooling, assuming you cook and heat water with propane or natural gas.

Here is an example of my power usage breakdown:

  • Minisplit (heating/cooling): 3,000 watts per day
  • Fridge: 780 watts per day
  • Lights: 100 watts per day
  • Cell Phone: 30 watts per day
  • Laptop: 240 watts per day

Total: 4,150 watts per day

How Many Panels Do You Need To Power A Tiny House?

how many solar panels for a tiny house

15 solar panels will power a typical tiny house. This assumes an average sized solar panel of around 300 watts, which would generate around 4,500 watts of power from the sun. This would cover all your power needs including some heating and cooling, but require you to have a gas cook range and a propane heated hot water heater. If you live in a particularly cold climate, you’ll most likely need to supplement your heating with a propane heater too.


How many solar panels can you fit on a tiny house roof?

how many solar panels can you fit on a tiny house

Generally speaking, you can only fit around 2 solar panels on a tiny house roof. This presents a real challenge because today you can really only expect to make around 20 watts per square foot of solar panel in ideal circumstances. That means you’re only going to be able to fit around 600 watts of solar production on a tiny house roof, which isn’t a whole lot.

Mounting Solar Panels On A Tiny House Roof

mounting solar panels on a tiny house

Many people want solar panels on the roof of their tiny house, but I opted for a ground mounted solar array, which I highly recommend. Tiny house roofs only have around 200 square feet of space and since most roofs are pitched, you can really only mount panels on one side. This means you only have around 100 square feet of space for panels.

What I did was mount my solar panels on stands on the ground. After considering all the options: roof mounted, pole mounted, solar trackers, and fixed ground mount, I’m really happy with my decision.

solar panels for homestead

The benefits of a ground mounted array are huge: being able to easily clean my panels, clear off snow that covers my panels after a snow fall, keeping the panels cooler (increases their efficiency) and being able to shade my house while placing the panels in an open field.

The biggest benefit of ground mounting my panels is that I could have a way bigger solar panel array. This meant instead of 600 watts on the roof of my tiny house, I could put 4,000 watts on the ground in the field right next to my tiny house.

My Tiny House Solar Panel System:

My tiny house solar panels system

To get your tiny house setup on solar you’ll need the following parts: your panels, batteries, a charge controller and an inverter. Simply put, your solar panels take the energy from the sun an converts it to DC power, that then flows to the charge controller which regulates the flow of power to the batteries or the inverter, the batteries stores power for later and the inverter converts the DC power to AC power, which your house uses.

solar panel system parts list

Here’s the key details of my solar power system:

  • 3,975 (3.9 KW) of panels Schneider SW 4024 – fifteen, 265 watt panels
  • 1,110 amp/hr battery storage
  • 24 volt system

My Tiny House Solar Setup:

  • (15) Canadian Solar CS-6p 265 Watt Poly Black Frame
  • Schneider SW 4024 Inverter
  • Schneider MPPT 60 Charge Controller
  • (12) Trojan L-16 6v 370 AH Flooded Lead Acid Batteries
  • Schneider System Control Panel
  • Schneider Interconnect Panel
  • Midnight Solar MNPV 80AMP Dinrail Breaker
  • Midnight Solar Surge Protection Device AC/DC
  • 50 Amp RV power Inlet

How To Build A Solar Power System For Your Tiny House

how to build a tiny house solar panel system

Before anything I needed to determine the best placement for the solar panels to make sure it had good solar exposure and didn’t fall into shadows too much. To do this I used a tool called a “solar path finder” which is a semi reflective dome that you position at the location, then snap a photo.

The photo is then loaded into a program and spits out a whole bunch of calculations.

solar path finder tool for calculating solar gain

Calculating Power Production

calculating your power needs

Once you upload the image into the software and then trace the tree line outline, you enter in your location, date and time. It then can calculate how much power you’ll produce based on 30 years of weather patterns for your exact location and tree coverage. Then it spits out all the calculations:

solar pathfinder reading from photo

solar power production chart

With that in mind, I knew what I could expect out of the system I had designed. It also was a way to verify my assumptions.

Once I verified that the system was going to be well suited to my needs, I had to build my panel support racking. I did this out of pressure treated 4×4’s that were each 10′ long. These things about 300 lbs each so I don’t have to worry about the wind picking up the panels.

I opted to build them because it was cheaper than some of the turn-key option out there and most of the for purchase ones required me to cement in the ground; I rent my land, so I wanted a mobile solution. If I remember correctly it was about $500 in materials to build this part.

solar panel supports for panels

Many people have asked why I didn’t mount these on my tiny house roof. You technically can mount on your roof, but honestly, the number of panels that you need to practically power your house is too many for the roof.

There are some other major bonuses of being on the ground:

  • Much cooler, roofs are very hot places in the summer and solar panels drop in efficiency when hot
  • I can put my house under deciduous trees, this means in summer I’m in the shade, in winter I get the solar gain
  • Way easier to clean and monitor

solar panels outside my tiny house

Cleaning your panels is pretty important because you loose efficiency as residue (bird poop) builds up. Also, as I learned just a few days ago, when it snows, you need to clear your panels. Cleaning becomes super simple and a lot safer when you don’t have to climb onto a roof via a ladder.

Just this week we got a decent snow, 3 inches, which is quite a lot for Charlotte. The first thing I had to do when I woke up was clear off the panels because, with the snow, they made no power. This was compounded because since it was cold, I needed more heat. I can’t imagine having to drag the ladder out and try climbing on an icy roof… No Thanks.

Choosing To Wire For AC Or DC From Solar

wire your home for AC or DC on solar

Many people have read around the internet that DC (direct current) is a more efficient power way to power things. Generally speaking, everything in a traditional house is wired for AC (alternating current), but if you’re putting solar in a tiny house and building your own house, the question becomes relevant when you’re starting from scratch. Solar panels produce DC power, so you have to decide how you’re going to handle it.

tiny house kitchen powered by solar

Most of the advice to wire a house for DC power comes from older sources who haven’t updated; these could be old articles written on the topic (consider anything more than a year out of date with how fast solar is improving) or from someone who hasn’t caught up with the latest equipment.

Back in the days, the drive to wire a house in DC power comes from two main things: there was power loss through inefficient inverters (converts from DC to AC) and from the fact that on paper DC is, in fact, more efficient.

Where this falls down in modern times is that inverters have come a long way and while there is some loss in power through the converting of AC to DC, it’s quite minimal. The other factor here is that any inefficiencies (of both the conversion to AC and the less efficient nature of AC) can be easily offset by the addition of 1-2 panels to your array.

This begins to make even more practical sense today because if you wire for DC, you’ll be limited to DC powered appliances, which typically cost two to three times the cost of their AC equivalents. That all means that you can actually have more power with AC, even after the losses through inefficiency, for less money. This is because the savings from going to AC appliances over DC will leave you with more cash, even after you buy 1-2 more panels.

To put it simply, convert to AC, add a few more panels to your array and stop worrying about AC vs DC.

Installing Solar Panels For My Tiny House

Installing Solar panels for my tiny house

After calculating the ideal location and building my stands, I installed the solar panels. This part was pretty quick and the stands worked out perfectly. The panels are 250 watt Canadian solar panels. They are wired in groups of three, then paralleled into the system. To give you a sense of scale, these panels are 3.3 wide and about 4 feet tall.

Building My Battery And Inverter Cabinet

building a cabinet for my batteries and inverter

Next, I built a cabinet to house all the gear. I wanted a stand alone space because the batteries are so heavy. At 118 pounds each, plus cabling and other equipment, the whole unit is over 1,100 lbs. The top and bottom sections are divided so that the gasses from the batteries don’t go up into the electrical section for a very important reason.

solar power cabinet

Looking at the cabinet, on the sides of it, you can see the vents. When you use lead acid (LA) batteries you have some off gassing as the batteries discharge and recharge. These gasses are volatile and can ignite, possibly leading to an explosion. To take care of this I installed two vents like this which provide adequate venting.

battery vent

Choosing Batteries For A Tiny House Solar Panel System

choosing batteries

I choose lead acid batteries over AGM (absorbent glass mat) because LA’s have more cycles and cost a bit less. Lithium Ion at this point is cost prohibitive, around $10,000 for the equivalent capacity. I choose these 6 volt batteries because it was more economical over other options and trojan is a pretty reputable name in the industry.

My batteries should get about 4000-5000 cycles (11-14 years) before I need to replace them. I figure in about 5 years battery technology will have progressed so much I’ll change early. New batteries will cost me about $5,000 of the lead acid variety.

solar batteries for a tiny house

Wiring My Batteries For 24 Volts

wiring batteries for 24 volt

The batteries are wired in series parallel. The batteries are 6 volt each, in series of 4 the create a 24 volt unit. Then I have two of these 24-volt units in parallel. The reason I choose to go 24 volts over a 48 volt (which is more efficient) was that the equipment was a little cheaper and it allowed me to future proof my setup.

Future Proofing My Solar Panel System

future proofing my solar setup

Going with a 24 volt system also allowed me to select components that I could add more panels and batteries very easily without doing equipment upgrades (just a factor of the abilities of the units I choose). This way I can add up to 15 panels and a lot more batteries without upgrading the electronics. A big draw for me to the system I choose was that I can also stack these inverters, so if I ever go to a normal sized house, I just add another unit and it just plugs into my current one.

Wiring A Tiny House For Solar

wire for a tiny house for solar

In this photo going left to right: Din Breaker Panel, Charge Controller, Interconnect w/ control panel, inverter.

solar power connection panels

In general, the power flows in the same manner (but not exactly).

  • Breaker Panel: manages power from solar panels
  • Charge Controller: manages power to batteries etc.
  • Interconnect: a main junction box and breaker, holds control panel interface
  • Inverter: takes power in many forms then outputs to the type of power you need

How To Connect Solar To A Tiny House

how to connect a tiny house to a solar array

Once the power goes through the system it outputs from the inverter as AC power. This AC Power flows out through a huge cable that you can see sticking out of the bottom of the inverter then goes right. From there it runs to this:

This is a 50 amp RV style plug. The reason I did this was twofold. City inspectors are less picky when it comes to non-hard-wired things. This setup also lets me roll into any RV campground and hook up seamlessly.

The plug goes into a 50 amp RV female receptacle. This is important that you don’t have two male ends to your cord. This is dubbed by electricians as a “suicide cord” because if you plug into a power source, you have exposed conductors that are live; accidentally touch them, you complete the circuit and zap!

how to connect solar panels to a tiny house

You want a female end to your cord so that you reduce the chance of being shocked. I also turn off my main breaker at the power source when I make this connection, then turn it back on.

If all these mentions of watts, volts, amps, amp hours etc are making your head spin a little, you may need to go back to the basics. I have an ebook called Shockingly Simple Electrical For Tiny Houses which guides you through all the basics. As of now, it doesn’t go too deep into the solar aspects, but the basics of electrical, wiring, power systems and determining your power needs are covered in depth and designed for those who are totally new to the topic.

So once the power passes through the power inlet it goes to the panel. Near the bottom you can see the backside of the power inlet, it has a large black cord coming out of it, into the box and ties to the lugs. From there it goes out to the house.

Grounding Your Solar Array

grounding solar panels

Here is my grounding wire for my system. This is actually one of two, another is located at the panels themselves. My house is also grounded to this through the cable hook up and to the trailer itself.

A really important note: ground depends on a lot of things, one of which is if you house electrical panels is bonded or not, if you don’t know what that means, read up on it, it’s very important.

ground solar panels

Using A Backup Generator

using a backup generator

The other component of this system is the generator which I used for the first two years and then opted to upgrade my system because they were such a pain to use. In the winter months, I sometimes needed to top off my batteries every now and then, basically when it’s been really cold and very cloudy for a week or more.

I had a Honda EB2000i already which I really like. It’s very quiet and small. The one downside to the Honda is that it only does 1600 watts and only 120V and I needed more power and 240V. To charge my batteries, I had to have 240 Volts, which lead me to get another generator, a 5500 watt 240 volt Generac for $650. This generator proved to be a major headache and lead me to upgrade my system just to not have to use it anymore.

Here is a video that compares the two generators in terms of size, noise, output, and price.

Tiny House Solar Panel System Costs

how much does solar for a tiny house cost

The big question when it comes to doing solar or not is of course cost. Everyone would like to have solar, but costs are a real barrier. My decision was made pretty easily when the power company informed me that I would have to pay $15,000 just to run their power line to my house, only to have a power bill each month.

My initial version of my solar panel array and batteries cost me around $14,000 with the added benefit of no power bills ever again and a $7,500 tax credit back, the decisions was a simple one. I later upgraded to a larger system for another $5,000, of which I got another $2,500 tax credit.

So, for me, I was able to actually save money from day one. That said, I had to bank roll that huge cash payment which most people cannot do.

Here is a rough break down of costs for my upgraded solar panel system:

  • Inverter: $4,500
  • Charge Controllers: $1,200
  • Control Panel: $300
  • Batteries: $4,000
  • Solar Panels: $4,000
  • Breakers + Boxes: $800
  • Battery Cabling: $300
  • PV Wire + House Tether + Romex: $500
  • Electrician (labor): $2,000

Is Solar Practical For Tiny Houses?

can you run a tiny house on solar

In general, I think for tiny houses in one spot, solar is very realistic. Even if you don’t start out on solar, the cost savings of living in a tiny house can let you save up for the install pretty quickly. When I rented an apartment, I was paying $1500 a month, compared to my tiny house that costs me about $15 a month (not a typo). Living in a tiny house allowed me to save a ton of money while having a comfortable home.

So that’s the surface level details of the system, I’m going to be doing something in the future which will be a how to size, choose parts, hook up and all the other details of doing solar for your tiny house.

Your Turn!

  • Do you want to do solar for your tiny house?

Shedding Light on Solar Generators: Are Portable Solar Generators Worth the Investment?

Shedding Light on Solar Generators: Are Portable Solar Generators Worth the Investment?

Shedding Light On Solar Generators

I get asked a lot about solar generators when people find out I’ve been off the grid full time since 2013. People want to know if a portable solar generator will work for their needs, how to find the best solar powered generator, and how to determine the wattage and size needed. There is a lot of confusing information out there and the fast pace of solar innovation makes it hard to keep up with.

Jakery solar generatorUsually, the people drawn to portable solar generators are beginners in the solar world. It’s often the guy who lives in a typical house, but who would like to start dabbling in solar power. He might have a goal to live in a tiny house someday, or even to purchase a full solar panel system to power his regular-sized home.

It’s important to note the term “solar generator” is a bit of a misnomer. Usually, what people are referring to is a power pack with solar panels. It’s either a setup you can piece together yourself or purchase off the shelf. These are low-power units. They can also get expensive since they’re a turnkey solution, but they’re an excellent way to dip a toe in the world of solar.

solar panel arraySwitching to solar panels completely, without experience, is quite a daunting task (especially if you’re trying to power a typical-sized home). It’s also a significant investment, which I’m all too aware of after writing a $19,000 check for my solar panel system for my tiny house. But after getting over the initial pain of paying so much money for my system, it’s definitely worth it. In fact, it’s hard to describe how awesome it is–I literally haven’t paid a power bill for years! Not to mention that 55% of my system was eligible for a tax credit.

That’s why solar powered generators are a nice way to explore the world of solar without a huge commitment or undertaking. Most of the people asking about solar generators possess a DIY outlook. They’re often wondering if solar is something they can set up on their own. If they purchase a Harbor Freight kit, can they build a small solar power system themselves?

So, are solar generators really worth the investment? Here’s what you need to know before you spend the money on a portable solar generator.

Managing Expectations About Solar Generators

managing expectations on solar generators

My biggest piece of advice to anyone exploring solar generators or solar power, in general, is to keep your expectations realistic. Now, I’ve been on solar power for years, and I really like my system. That said, it was a lot of work and a big investment to set up. There are also limitations.

With a solar panel system, there will be adjustments to your lifestyle that is required when you go off the grid:

  • Bad Weather – if it’s cloudy for a week straight, you might be reaching for a blanket as your battery wanes.
  • Snow – Are you ready to get out and clean snow off your panels in a blizzard?
  • Something breaks – there is no power company to call, if your power goes out, it’s up to you.
  • Maintenance – Batteries to fill, terminals to clean, fuses to change, and panels to clean.

Before you go fully solar, a portable solar generator is an excellent gateway option. It allows you to explore the fundamentals of solar power generation and to understand how the larger systems work. It also lets you get an idea of the capacity (on a small scale) so you can scale up later. This is really useful because you begin to really grasp what you need to do different things.

How to run a tiny house on solar

Now, I’ll be honest, the smallest solar powered generators aren’t super useful. The smallest ones can’t charge more than a cell phone or a small laptop. Don’t expect that a small investment or even a small DIY solar generator kit is going to get you enough power to live off the grid or run your household appliances.

Most small solar generators are under 500 Watts (typically around 2-300 Watts). You’ll invest $500+ or so for the battery and power pack, and you’ll need one or two panels at $3-400 each. These solar generators won’t work for running your stove or your air conditioner (for those larger items, you’ll need a full solar panel system).

Figure where a traditional larger scale system with lead acid batteries you can get it for $1 per watt, in a solar generator you should expect to spent $2-$3 per watt because it’s turn key and often uses lithium ion batteries which are higher performing.

What Are Portable Solar Generators Good For?

What are solar generators good for?

Where portable solar generators really perform is when you’re camping, or if there’s an emergency. If you’re stuck in a hurricane or there’s a big power outage in your city, then a small solar powered generator is great to own. People often purchase them for emergency preparedness kits and shelters. You may not power your whole house on it, but at least you’ll get light and the ability to power your small electronics, which is lifesaving in certain scenarios.

These little solar generators are also handy for tailgating and camping. If you own an RV or a teardrop-trailer, you can use the portable solar generator to power your needs for a weekend trip. They’re excellent for keeping your phone charged or running a small amount of power to an item (like a light). If you tailgate often, a solar generator will easily keep your radio going without draining your car battery during the game.

What can you power with a solar generator?

Possible

  • Small Fans
  • LED Lights
  • Laptop charger

Maybe Possible

  • Television
  • Mini Fridge
  • Microwave

Not Possible

  • Refrigerator
  • AC Unit
  • Furnace

Solar generators work great for small fans, LED lights, charging your small portable electronics, and other small, low-power tasks. Some high-efficiency televisions work well with solar powered generators. You can charge a laptop or tablet with a solar generator, too.

I’ve also known many construction workers and builders who love these portable solar generators for keeping their tools charged on the job. It’s great to use a solar generator at a building site as a continuous source of power for battery driven drills, saws, power tools, and small pieces of equipment. Solar powered generators are perfect if your build-site is away from a power source and you’re working for a few days. If you’re building a cabin or a tiny house in a rural spot, then a solar generator will help keep your tools going.

There are also many jobs where a solar generator won’t cut it. These items require too much power to run efficiently (or even at all) on a portable solar generator.

Things that won’t run well on a portable solar generator include:

  • Anything with a heating element: Coffee pots, hairdryers/straighteners, hot plates, toaster ovens.
  • Small appliances: Microwaves, slow cookers, blenders.
  • Large electronics: Desktop computers, game consoles, and some projectors.
  • Heating and air conditioning: Any size AC unit (window or otherwise), heaters of any size.
  • Refrigeration: A small modern fridge will only run a few hours on a large solar generator.

Like most jobs, it’s all about having the right tool. This is advice I preach in any scenario: if you want to do a good job, you need to invest in the right tools. If you pick the wrong tool for the job, it won’t perform up to your expectations.

How a Solar Generator Works

How do solar generators work?

solar generator parts list

The battery is a power bank. Depending on the voltage of your battery, it holds power until you’re ready to plug-in and run your device. These batteries are also used to charge phone, computer, and power tool battery packs as well. Solar batteries are often finicky and delicate. While many of these solar generators use higher quality lithium ion batteries, it’s still best to use caution so you don’t damage them.

When people think of solar, they forget about the battery component, but it’s essential. If your power source is the sun, then what do you do on a cloudy day? What happens at night? Solar isn’t consistent. The battery stores the power, so it’s available whenever you need it. If the sun is making enough power, then it’s shunting the energy into the item you’re powering. If you overuse your solar source, then your generator goes into the battery.

The other component of a solar generator is the inverter. The inverter converts DC (direct current) power into AC power, which is used by most tools and appliances. AC typically runs at 110-240 volts in the USA, so the inverter ramps up the voltage from the battery to 100-240 volts.

running air conditioning with solar panels

Some people prefer the DIY approach to solar generators. They buy the base pieces of a DIY system and put it together themselves. This is certainly possible, but it’s often a challenging project for a beginner. What I’ve seen happen time and time again is people start down the DIY path but get frustrated and go out and buy an off-the-shelf solar generator instead.

How to Decide Which Solar Generator You Want and Need

what is the best solar generator to get?

If you’ve weighed out the pros and cons of solar generators and feel like you have a realistic idea of what you need (and what the solar generator can do), it’s time to decide which solar powered generator is best for you.

My biggest recommendation for anyone looking to switch to solar power is to figure out precisely what you want to charge first. Determine your power requirements (what’s sometimes called your power profile). What is the breakdown of exactly what you need to charge and plan to use when you use your solar generator?

To figure this out, I’ve created a workbook to help you determine your exact power consumption. Exploring your needs first is such a critical step, even if you’re starting with a portable solar generator because these are big purchases. Even a small solar generator with panels and a power bank will cost you a significant amount. You’ll want to get exactly what you need upfront before you invest a few thousand dollars on something that can’t do more than recharge your phone or run an LED light.

Once you’ve decided what you want to charge and exactly what size solar generator you need, it’s time to determine your approach Are you more of a DIY type? Do you feel comfortable buying the pieces and building a solar generator yourself, or would you feel more comfortable with an off-the-shelf generator system?

If you buy off the shelf, it’s important to ask the following questions:

  • Can you plug it into the wall with a power manager for back up?
  • Does it do what you need it to do?
  • Is it compatible with other connectors and components or does it only use proprietary components?
  • Is it portable enough for your needs?
  • Can it be charged by a wall socket, car outlets, and solar panels?
  • Does it come with a wide range of power hookups?
  • Can you daisy-chain panels to get more power?

Buying off-the-shelf is a great option, but it’s important to note that different brands use different proprietary connectors (so you must buy their brand’s solar panels and components). Always check before you start investing in a product that won’t work with components you already own.

Solar Generators To Compare

Comparing solar generators

When it comes to solar generators, there are three leading brands out there: Jackery, Goal Zero, and Inergy. Here’s what I’ve learned about each brand to help you compare.

Jackery Explorer

Jackery has three sizes of portable power stations (100 Watt, 240 Watt, and 500 Watt). I had the opportunity to check out the Jackery Explorer 500 Watt Portable Power Station as well as the Jackery Solarsaga 100 Watt Solar Panel. The Power Station looks a bit like a fancy lunchbox with a battery and a bunch of power hookups. This worked well.

The one feature that made this solar generator my preferred choice was that all the connectors were standardized. Other companies used proprietary connectors which was an instant deal breaker for me, making Jackery an easy choice.

Jackery Solar generator
Some aspects I really liked about the Jackery Solar Generator:

  • Doesn’t use proprietary connectors.
  • Well-built, with a robust solar panel (this one impressed me with it’s sturdiness).
  • Compact and easy to use.
  • Lightweight (the Power Station is 13.32 pounds).
  • LCD screen with charge/discharge data and battery life status.
  • Quiet operation.
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Goal Zero Yeti

Goal Zero offers an array of Yeti power stations. These power stations mainly feature lithium batteries and are available in a range of prices and capacity. They’re built to pair with the Goal Zero solar panels, but with some configuring, they can also pair with other panels.

Goal Zero solar generator kits
Some pros and cons of the Goal Zero Yeti systems:

  • Portable and most include Wi-Fi capabilities, as well.
  • Overall positive reviews on the Goal Zero products.
  • Not recommended for radio communications.
  • Concerns about the AC inverter not holding up and shorter battery life.
  • Configuration is necessary to pair with other brand solar panels.
  • Widely available on Amazon, REI, and other retailers.
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Inergy Apex

The Inergy Apex Portable Power Station (previously Kodiak) also has positive reviews. The Apex offers a peak 1,500 Watt pure sine wave inverter and 1,100 Watt-hours of peak battery capacity. It’s also lightweight and compact.

Inergy solar generators
Some pros and cons of the Inergy APEX Portable Power Station:

  • Portable and lightweight.
  • Optional battery expansion option, which is helpful for upgrades and kits.
  • Doesn’t support the Neutrik adapter for third party panels.
  • 500 Watt max output.
  • Reliable and durable according to reviews.
  • The LCD screen is easy to read.
  • Quiet operation.
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When it comes to solar generators, my biggest word of advice is to manage your expectations. You aren’t going to be able to run your refrigerator, blender, microwave, and television on a solar generator. It’s not going to happen. You can, however, use a solar generator to learn how solar works. It can help you get used to the quirks of relying on solar power before you scale up to a full system.

Solar generators are great for camping, charging tools, and for hobbyists. If solar energy is something that interests you and you don’t know where to start, solar powered generators are a cool option to explore.

Your Turn!

  • Have you ever used a portable solar generator?
  • What would you like to power with a solar generator?

How to Run Air Conditioning On Solar Power

How to Run Air Conditioning On Solar Power

Today I wanted to share information about running air conditioning on solar power.

When I was first planning to move into my tiny house, considering the possibility of running a solar powered air conditioner and cooling system weighed heavily on my mind. After all, living in a humid state, I’ll tell you, I’m one who can’t tolerate the heat. This is especially true, coming from New Hampshire—I’m a cold weather guy and here in North Carolina, it gets hot! An AC unit is critical, even if you’re running on solar power.

How to Run Air Conditioning On Solar Power

Well, Charlotte’s heat really came full force this week.  I know for many their climate doesn’t get as humid as it does here, so there are other options besides running a house air conditioner. Unfortunately, here, it’s necessary.  Without AC I can’t really sleep, even using a fan to passively cool the house.

Right now, the humidity is still tolerable, but it’s HOT and the humidity is coming soon.  It has been in the high 80’s and low 90’s outside, which made my house in the mid 90’s inside.

So, what are the tiny house air conditioner solutions? How do you cool off your tiny house (even off the grid) and beat the heat?

Deciding to Buy a Solar Powered Air Conditioner

I thought I’d do a post today because I’ve been able to run a few real-world experiments with my tiny house and solar powered AC.  I haven’t seen any experienced reporting on the topic of running air conditioning on solar power, so I figured it would be helpful for you all to hear what I did.

When it comes to cooling a tiny house, there are three areas to look at: isolation, such as shade, seals and insulation; ventilation, such as fans and setting open windows for cross-winds; and artificial cooling. Many tiny homes, by their portable nature, don’t have basements, where you can retreat if you need to cool off. Since heat rises and your entire home is above the ground, you need alternative methods to cool down.

Desert-dwellers may be able to rely on swamp coolers and evaporation-based cooling systems Here in the humid part of the world, these setups never work because our air is already humid. It’s impossible to cool humidity with MORE humidity.

Isolation, using shade and insulation to your advantage, is important if you live in off the grid. You can keep your house fairly cool by simply, closing off your space, especially in the heat of the day. This is why I decided to park my tiny house under the trees for shade and run my solar panels in the wide-open field.  While these methods help and should be employed, of course, chances are you’ll still need to rely on a solar powered air conditioner system to get through the hottest days.

After doing my research on what unit would work best with my solar panel set up and power levels. I ordered my unit before I found an installer. I have yet to hook up my mini split air conditioning system (see the update below where I talk about life on solar with my mini split) because it has taken me a long time to find a HVAC installer who would install my mini split AC. As I discovered after buying my mini split unit, most installers insist they need to sell you the air conditioning equipment if they are going to install it. Obviously, this was an unknown factor to me when I ordered my house air conditioning unit…but these are the bumps in the road you experience when you live The Tiny Life.

Fujitsu air conditioning system.

Fujitsu Air Conditioning System

How Much Power Does an Air Conditioner Use?

For heating and cooling, I opted for the Fujitsu 9RLS2 which is a 9,000 BTU Ductless Mini Split Air Conditioner Heat Pump System with a SEER (Seasonal Energy Efficiency Ratio) rating of 27.  To give you an idea, older, less efficient mini split air conditioning systems have a SEER rating of around 8 to 10. Modern air conditioning systems, labeled highly efficient may have a rating of 15 or so, but most today are around 12-13.

The SEER rating was very important because my tiny house solar panel system simply couldn’t handle the less efficient cooling systems.  The SEER rating is determined by BTUs (British Thermal Units) to Watts.  The higher the number, the better.

The other big reason I choose this particular mini split air conditioning unit versus a standard window air conditioner was aesthetics.  My air handler is wall mounted, out of the way and above eye level.  This has a few advantages. First, it keeps my limited square footage clear of clutter. Secondly, it keeps my windows looking nice because there’s no window unit blighting a good design. Lastly, keeping it above eye level also helps you forget about it because as humans we don’t often look up.

Tiny House Friendly Air Conditioning

While I’m working on getting an HVAC installer lined up to put in my Fujitsu Air Conditioning System, I’m using a portable air conditioner, which has worked pretty well.  The downside to using a portable AC unit is it takes up a lot of space and it’s not as efficient. The portable AC unit I’m using has a SEER rating of 12, which means my new mini split system will be 225% more efficient once it’s installed.

UPDATE:  It’s been several years now since I first wrote this post and I’ve been living full time totally off the grid and it’s wonderful.  I was able to find an installer to pull the vacuum in my system and this thing cools like a dream.

During the summer the AC pulls between 450 watts and 700 watts, on “powerful” mode it draws about 1,000 watts.  As a side note for heat, it pulls about 700 watts to 1,000 watts, 1,100 on “powerful”.

If I had to do things all over again I’d go with a Mitsubishi brand mini split over the Fujitsu, because they seem to be a bit more well-designed. The Mitsubishi has also the critical feature of auto dry, which dries the coil of moisture before shutting down.  I’ve had to clean my coils several times in the 5 years and a drying feature would almost eliminate this.

Stress Testing My Portable AC Unit and Solar Panel Power System

I decided to “stress test” my solar panel system by turning the portable AC unit on high and setting the thermostat to 60 degrees. I wanted to see how long it would take for my solar panel system batteries to bottom out (50% discharge).  The charge controller on my solar panel system automatically turns off the power to my house if the batteries power discharges down to 50%. This automatic shut off on the solar panel system prevents damage to the batteries by discharging too deep.

Solar panel batteries and a chart of number of cycles and depth of discharge to determine battery life.

As you see by the chart above, keeping battery discharge at 50% or above gives me a little shy of 2,000 cycles or 5.4 years for the life of my batteries.  I plan to add another set of four batteries to the solar panel system pretty soon, which will give me improved capacity and keep my discharge rate much higher than 50% (though I don’t often get that low).  In about 5 more years we should start seeing really interesting battery technologies hit the market. This should coincide with the life of my current batteries, so I plan to hop on these new technologies as soon as my batteries begin to fade.

UPDATE:  It’s been several years now since I posted this. Last year I bit the bullet and added 6 more solar panels and 4 more batteries.  This was mainly to avoid needing a generator in the winter months because they’re a royal pain.  Cooling my house in the summer is still pretty simple since my house is so small.  I usually turn my air conditioner on when I get home and shut it off when I leave.  This allows the batteries to fully recharge and doesn’t really impact cooling.

My solar panel battery stress test was an interesting experiment. I ran the less efficient, portable air conditioner for three days solid, starting with a very warm house.  At the end of the three days, I was very close to hitting 50% on my battery reserve, but it didn’t ever dip below that threshold.  I decided, after three days, the test had gone on long enough to get an accurate reading and I stopped the test.  I typically turn off the AC whenever I’m gone.

Following the test, the past few days were a bit trickier because since my solar panel battery system was so low, I needed it to build back up. Unfortunately, we had a series of cloudy days, making it tough to get more energy.  While I’ve had plenty of power to run the AC overnight, the battery reserve is lower than I’d like.  To give you an idea: on a normal sunny day my solar panel power system makes about 8,000 Watts, but on a cloudy day (when the clouds are very thick with no gaps) I get between 2,000 and 4,000 Watts.

The Advantage of Solar Powered Air Conditioning

When it’s hottest and the sun is shining the brightest, I can make lots of power!  This allows me to run the AC full blast to keep my house nice and cool. Even with the air conditioner on high my solar panel system still makes enough power to add 2,000 Watts into the batteries. Compare this to heating, where you often need the heat the most at night when the sun isn’t out. This results in a major drain on your batteries.  Compounding the issue of running heating off solar panel energy, heaters are more energy intensive than cooling and air conditioning units.

The other night I decided to conduct another experiment.  I got my house very cold by running the AC unit. Then, I turned off the cool air at midnight (when I usually go to bed).  Outside it was about 65 degrees and about 45% humidity–so not bad.  I left all the windows closed to see how much my body heat would warm up the house. In the summer, opening the windows doesn’t often doesn’t help anyway, even if it is cooler outside because the humidity increases the “feels like” temperature.

As it turns out in just three hours my body heat warmed up the loft of my tiny house to the point I woke up from being so uncomfortable from the heat!  Around 3:30 am I woke up and it was very hot in my loft.  I checked the time and was surprised how little time it took.  I should note when I fall asleep, I usually stay asleep all night, even if I get warm. The fact I woke up from the heat, shows how uncomfortable it was in my loft because it takes a lot!

Fortunately, I had prepared for this and all I did was crank open my skylight (the highest point in my house) and the loft end window. I switched on a fan to draw in cool air.  Within 5 minutes the whole place dropped about 5 degrees and I was back asleep.

So that has been my real-world experiences with the tiny house, AC units and solar panel power systems.  I know I had always been frustrated by not enough stories and real-life examples of AC and cooling issues, so hopefully my story will help others.

Key resources for those wanting more technical stuff:


My Setup For Solar Power

  • Details of my tiny house solar panel system
  • Calculating solar power system requirements
  • Building racks to hold solar panels
  • Adding a solar panel gear cabinet
  • Understanding solar panel electric systems
  • Choosing a backup generator