RV air conditioning on batteries and solar. Can you do it? My goal is to be electrical energy independent, this includes air conditioning on batteries and solar. I can run my RV air conditioning from my batteries all night long. I installed a large battery and solar electric system. I can run my RV air conditioning from my battery bank and recharge the batteries at the same time from my solar array. The RV air conditioner runs on batteries and solar replaces (most of) the electricity that the RV consumes including the air conditioner.
This article includes almost five years of data and explanations. I started writing it down in 2020 and included updates from every year since then. It is no longer just an idea, we have the answers. Here are the details of how we operated before we had our big lithium battery bank and solar array. RV Electricity the Hard Way, without solar or lithium
Notes pertaining to the pictures — most of the pictures in this article are decorations. Sorry, it is hard to photograph air conditioning and impossible to photograph the electricity needed to run air conditioning.
Everything you need to know about to run your RV air conditioner on batteries and solar.
Table of Contents
Frequently Asked Questions!
Sorry if you get the same answers more than once. To completely answer each question sometimes similar information will be provided for slightly different questions.
Can you run your RV air conditioner only with batteries and solar panels?
The answer is yes you can — if you have a big battery bank and a large inverter. Then you have to install a big enough solar array to replace the energy that the air conditioner consumes. I also had to rewire my electrical panel so that my inverter would supply the electricity from the batteries to the air conditioners.
My system requires a large inverter. I have friends that have direct-current (DC) air conditioners (almost experimental models) that don’t require an inverter. They can run their air conditioners longer than I can from the same battery power because this design is more efficient. My big inverter wastes about 10% of my available power and converts the wasted electricity into heat.
Can you run an RV air conditioner only on solar panels? (without a big battery bank)
Not in my system, my solar is wired to recharge my batteries it is not wired directly to the inverter so I can’t run my air conditioners directly from solar. This wasn’t my design goal because I want to run my air conditioner when I want air conditioning including after sunset. This won’t work without a big battery bank.
Is it practical to install an RV battery bank big enough so that you can run an air conditioner?
For me, the answer is yes. For you, the answer depends on your priorities. For me, it is practical to install a battery system big enough to run my air conditioner. I wanted to run my air conditioner at night when I was sleeping. So it was critical that I have a big enough battery bank to accomplish this goal. Additionally, the battery bank also allows me to run my RV for two and a half days without any additional electrical energy when I don’t need my air conditioner.
How many batteries does it take to run an air conditioner?
I can run one of my air conditioners for about one hour on each one-hundred amp-hour lithium battery. I have nine one-hundred amp-hour lithium batteries. So if I did this, after nine hours, my batteries would be empty. There are several ways I could make this better and have friends that have more efficient (smaller RVs) and more efficient electrical systems that can run their air conditioners longer from each battery.
Can you run your air conditioner on your solar without depleting your battery charge?
Not for my system. I will explain this next. Being able to run the air conditioner, say in the afternoon without depleting the battery charge was a hopeful goal but I have to say that I really didn’t completely accomplish this goal. If I were to increase my solar array size by perhaps 30% then I am pretty sure I could do this. Part of installing more solar panels would provide additional shade on my RV roof.
How many solar panels does it take to run an air conditioner?
The answer for my air conditioner is more than 2000 delivered watts per hour. I have 1800 watts of solar but can only deliver 1400 watts. Solar panels are only 100 efficient in a laboratory. On an RV roof, they are never going to deliver their full rating. For many RVers, the limit is roof space. For others, the limit is money. For me, the answer was no. The reason it is no is because of diminishing returns.
Additionally, I still have my RV generator, so, I have options.
My first 900 watts of solar panels provide most of the energy I need on a typical day. This includes running my refrigerator all day long. My second 900 watts of solar panels means that I usually can achieve a full recharge before noon after a typical night’s energy use. Then in the afternoon, I can use the extra energy and live without any concerns that I will run out of electricity. When the sun goes down I almost always have a 100% charge on my battery bank. Assuming that I didn’t need air conditioning at night, then I will deplete about twenty five to forty percent of my battery charge before the solar array starts charging the next day.
I had an advantage from the beginning.
My RV had an initially lower cost to install a huge battery bank and solar than many similar RVs. I already had a very capable Magnum Inverter/ Charger when I installed a massive battery bank. I have plenty of battery power and I can run one of my air conditioning on batteries, starting with a full charge, for about eight hours. I also have a large-capacity generator that can run both of my air conditioners and recharge my batteries at the same time.
Is it hard to run your air conditioner from your solar?
The simple answer is that to get solar to work, you have to park the RV in the sun. When you park your RV in the sun, then your air conditioner has to work much harder than if you park in the shade. If you park in the shade then the solar won’t work. It is better to park in the shade and run your air conditioner from a generator and at the same time, charge your batteries so that you can run your air conditioner from your battery bank at night when you are sleeping.
Having a large battery bank and a large solar array isn’t just to run the air conditioner, but rather to supply all my electrical energy needs when I don’t need the air conditioner.
Could I build an RV that could operate completely on solar?
Not if you include driving the RV on solar only.
I am convinced that I could achieve everything other than driving, in a carefully designed RV. The design would have to have this as a goal from the beginning. One of the design criteria would be to have a completely clear roof. RV roofs typically have lots of obstructions on them and that makes covering the roof with solar panels very difficult. I have an RV that balances travel with energy independence and makes travel easy. My RV also places a premium on space and comfort.
How long can I run my air conditioner from my battery?
I have a big battery bank and a big enough inverter. I can run my air conditioner at night when I am sleeping, (more than 8 hours per night) all night long. That makes me so happy and so much more capable than almost every other RV. The solar array is great, but not good enough to run my air conditioner continually while it is sitting in the sun.
How does my battery and solar work to run my RV?
The battery powers the inverter and then the inverter runs the electrical needs. The solar recharges the battery. The key is to have a big enough battery bank. Here is a link to a description. Why do we have a Hybrid Mongrel Battery in our RV? This past fall we replaced our lead acid batteries and made an additional electrical remodel. Here is a link to our new configuration. Can one lithium battery replace four lead-acid batteries?
Here is a link to the description of my battery bank. Make sure that you understand my meaning of an electric bucket. It is a very important part of this issue. Massive Electric Bucket
The next step is to install a large solar panel array. I wanted it to be capable of creating enough electricity to “run” the air conditioner with enough extra electrical energy to recharge the batteries at the same time. When I am not running the air conditioning my goal is to dump about 100 amp-hours of electricity into my battery as fast as possible. Installing our Zamp Obsidian Solar Array
I can easily hit 500 amp-hours per sunny day of charging. Sometimes, on a long summer day, I have created more than 1100 amp-hours in a single day. The problem is that the air conditioner can easily use everything the solar array can put out. Some people have suggested that we have too many solar panels or that they were wired incorrectly. Here is a link associated with that question. You have too many solar panels on your RV!
It is not my design goal to run my air conditioning on batteries and solar indefinitely, especially in the south, in the summer with solar power alone. Simply stated, I don’t have enough roof space to accomplish such a feat. But rather, I can easily achieve my goal of occasional use. My occasional use means all night long when necessary.
The details of RV Air Conditioning from Solar
Air conditioning on solar is a holy grail for RVs. The statement “from solar” is incomplete. You don’t run air conditioning on batteries and solar; instead, the solar charges the batteries. The batteries deliver the energy to the inverter, which in turn runs the air conditioner.
Running the air conditioner directly from the solar is a non-starter because you don’t only want to run the air conditioners just when the sun is shining. Rather you want to run the air conditioners when it is most important for you to have a more comfortable RV. For me, this means being able to run my air conditioner at night without the benefit of sunshine.
When do we use air conditioning on batteries and solar?
When we are sleeping.
Sometimes when we are boondocking it is quite warm at bedtime — air conditioning would be great. In this case, air conditioning would be a direct drain on the battery.
When generator use is restricted.
When we were camping in Death Valley, we got caught by the “generator police” at 7 pm because our generator was still on (we were standing outside). It would have been so nice to have air conditioning that night. Obviously, this situation has been repeated many times before we put in a large battery bank and solar panels. Since then I can’t think of any time this was a problem.
Here is a link to that story. Death Valley National Park
Another time when air conditioning on batteries and solar is great is when we are driving. We typically drive about one or two hours in the middle of the day. While we are driving, we can run our air conditioners, to keep the house cool and make the RV more comfortable during our travel days. Usually, we only use our dash air conditioner when driving, but occasionally we turn on the solar and battery-operated air conditioner.
Assuming we are traveling during the daytime (we always travel during the daytime) and assuming it is sunny (not always the case), the solar would still be charging the battery while we are driving and at the same time we can run our air conditioning on batteries and solar. We don’t use our engine alternator to recharge our lithium batteries. In this case, we wouldn’t need the solar. The reason we don’t use our engine alternator is that we have solar.
In the afternoon.
We could run the air conditioning on batteries and solar is in the afternoon. The afternoon is exactly when the air conditioning would be most appreciated. If the battery is full or nearly full then the air conditioning can run while charging from the solar. If the battery needs a charge, then starting the generator would both run the air conditioners and charge the battery from the generator and solar at the same time.
Using our RV Air conditioning as a heat pump
My air conditioning units are heat pumps. This means that since I can run the air conditioners, I can, if I desired, also use them to create heat. Heat pumps are far more energy-efficient than my electric room space heater. So I could create electrical heat using the batteries. I don’t have any reason to do this in that I also have two propane furnaces that are way more energy-efficient than any electrical heat source.
So how much electricity does an air conditioner consume?
It depends on how hot it is and whether or not I am sitting in the sun or in the shade.
RV air conditioners consume about 900 watts (each) per hour to run. (2021 edit, I was wrong my air conditioners can and frequently consume way more than 900 watts of electricity. I have real-world test results both while parked in shade without the sun hitting the solar panels and when sitting in the sun). In the same conditions, with a big solar panel array, air conditioning needs can be lower because the solar panels shade my roof.
Note about starting an RV air conditioner. (Our air conditioners used to pull much more than 3000 watts during start-up. Here is a link about how to tame the start-up spike. Micro-Air EasyStart
So, since each 100 amp hour battery holds about 1200-1350 watt-hours of useable energy when full, and assuming the battery is full when I start, each battery is able to run one air conditioner for 1 to 1.5 hours depending on compressor cycling.
In the same conditions, assuming I had the solar running at full tilt, I would be producing around 1400 watts per hour (1400 watts per hour assumes no shading and ideal conditions). So easy math says if I am consuming 900 per hour (2021 edit: more like 1500 watts per hour) and making 1400 per hour, I can charge the batteries at the same time as running the air conditioner.
(edit 2023: You may have noticed I said 900-1500 watts per hour this is way less than the 2017 watts of electricity that my air conditioner is rated at. The difference is that the compressor does not run continuously but rather cycles on and off. This was not true in Las Vegas in August 2017, but that was an extreme condition with temperatures of more than 110 degrees after sunset. At these temperatures, the compressor was on all the time.)
These calculations will not be replicated in real life except during ideal conditions. There are too many variables. One tree shading part of one panel can affect the output of three panels. Shade kills the output of solar panels dramatically.
Before we got the solar installed, I hoped that the solar should be able to run one air conditioner at full blast with no net drain on the battery. (edit 2022: this proved not to be correct. Almost always, even with direct sun on the panels, there will be a net drain on my battery.)
It also depends on the wind.
When it is windy, which is always the case when we are driving then the air moving across the skin of the RV cools and the exterior RV skin temperature is always cooler than when it isn’t windy. The outcome is that the air conditioner doesn’t have to work as hard and air conditioning is easier.
Additionally, solar panels also benefit from the wind and produce more energy when cooled. My maximum is still only about 1400 watts per hour and this is easy to achieve with cool panels. Plus, when we are driving we have the dash air conditioner running and this reduces compressor cycle time dramatically. So we run the rear air conditioner when driving.
My RV required an electrical remodel
When Tiffin designed our RV in 2008 they never anticipated that anyone would want to run the air conditioning on batteries and solar. It simply wasn’t on their radar. They were pushing the design when they included a residential refrigerator. To do this, Tiffin installed extra batteries, and solar to help run the refrigerator. Anytime air conditioning was needed, the answer was to start the generator or plug into shore power. Air conditioning on batteries and solar was not part of the design.
Ninety-nine percent of RVs coming off the assembly line today in 2023 are still designed the same way or with less capable electrical systems than our RV had in 2008. This includes our previous 2013 Tiffin which is electrically inferior to our 2008.
RV power math: 50 amp = 100 amps and 30 amps = 30 amps
This section pertains to plugging the RV into power at the campground. Just like your home, this service is supplied in alternating current (AC). Shore power or my generator feeds the “50 amp main” supply to the circuit breaker panel.
This supply is broken into two branches commonly named red and black, as associated with the wire color. Both the red and black wire can each supply 50 amps to distribution. Thus when you have 50 amp service you have two sources of 50 amp power. Thus 50 amps = 100 amps of power. In my RV, and I would venture to say all RVs with 50 amp service, one air conditioner is on the red wire and the other air conditioner is on the black wire.
When plugged into a 30 amp supply, then both branches share the 30 amp service and deliver the 30 amp to distribution. Thus 30 amps = 30 amps. The same is true for 20 amps. 20 amps = 20 amps
What we needed was a redesign inside the circuit breaker panel.
Here is a general overview. Alternating current electrical power comes into the circuit breaker panel from three different sources. The three sources are shore power, generator, or inverter. Shore power can deliver 100 amps (AC) of power to the circuit breaker panel. The generator can deliver 55 amps of power to the circuit breaker panel. The inverter from the batteries can deliver 27 amps of power. The 2008 circuit breaker layout would not allow me to run air conditioning on batteries and solar– so I rewired it.
One of the ways you could wire the RV would be to have a manual switch that would select the power source. The way nearly all RVs, with factory-installed inverters, are designed is that there is a transfer switch that chooses between the generator or shore power. Our default condition is that when the generator is on, it is the source of electrical power.
Inverter power is delegated to a secondary role and is only used when the generator or shore power is off. This is accomplished via a sub-panel. The sub-panel is powered from either the inverter directly when operating on battery power or from either shore power/generator when that is our power source. To run the air conditioning on batteries and solar the power source would need to be from the sub-panel.
Electrical flow in the circuit breaker panel
This is how my RV works — it is very likely that your RV does not work the same way!!! If you don’t understand it then don’t monkey with it.
Shore power or generator power enters the circuit breaker panel via the 50 amp circuit breakers (one red, one black) and energizes the red and black bus. From the red and black bus, part of the power (30 amp red and 30 amp black) is then routed to the inverter from a circuit breaker labeled “inverter out”… The power passes through the inverter and is returned to the circuit breaker sub-panel on the “inverter in” circuit breakers. (30 amp red and 30 amp black).
The sub-panel routes the electricity to the sub-panel circuits. Without the change to the sub-panel, I would never be able to air the conditioner on batteries and solar. I needed my air conditioners on the portion of my electrical distribution powered by the inverter.
If electricity from the generator or shore power is not available, then the inverter will convert battery power (DC) into (AC) power and supply the sub-panel with electricity to operate sub-panel circuits. My microwave and refrigerator operate from the inverter and thus will run with or without shore power. (assuming the batteries are full enough to operate the inverter)
Remodeling inside the circuit breaker panel
The circuit breakers that operate the air conditioners were on the circuits only supplied by generator or shore power. Thus the air conditioners could not operate from the inverter (even though the inverter was on and big enough). Because the air conditioners were not on the panel powered by the inverter they could not be powered by the inverter.
Hence to achieve air conditioning from batteries, I rewired the inside of the circuit breaker panel to move them to the portion that is powered by the inverter. Now they can operate from the inverter.
RV power over allocation — caution
An older small house usually has a 200 amp (AC) power service. RVs almost always have a maximum of 100 amp (AC) service and as outlined above in many cases have less than a 100 amp service. It is easy to use more than 100 amps (AC) in an RV.
My re-wire creates a potential for an over-allocation of electrical power. I looked carefully at this issue, Tiffin had already over-allocated the electrical circuits on the sub-panel. By adding the air conditioners, I have increased the potential of turning on too many devices and thus tripping the circuit breaker interrupting power. You cannot ask for too many amps, all at the same time or the circuit breaker will trip. So even though I am over-allocated, I am unlikely to trip my circuit breaker. The reason is that the items that could be used when operating on battery only, are unlikely to be used when operating on battery only.
Where are the power hogs?
My power hogs are the inverter (when operating as a battery charger), air conditioners, water heater, engine heater, electric space heater, convection oven/microwave, clothes dryer, hairdryer, and instant pot. The refrigerator also needs to be included in this discussion. The refrigerator does not consume lots of power, all at one time, but is a large power load and an essential item.
Of the above items, the only things that I can never operate from the inverter are the engine heater and water heater. These items are only hooked to the main bus, not the secondary bus. I can only use them when hooked to shore power or when running the generator. I cannot run them powered by the inverter.
My power hogs that are able to operate when I don’t have external power are air conditioners, electric space heaters, convection oven/microwave, clothes dryer, hairdryer, and instant pot.
Items that I will rarely use on battery power are the air conditioners and convection oven. Items that I am likely to never use when on battery power are the clothes dryer, and electric space heater. (2022 edit: I was wrong, sometimes we run our clothes dryer from our batteries, but only occasionally when we have plenty of solar power. We also don’t hesitate to run the convection oven, hair dryer, or instant pot.)
If I attempt to operate too many of the power hogs at the same time, I will trip the circuit breaker.
Important Items when on battery only
Used all the time = refrigerator. Occasional use = microwave, and instant pot. Rare use = hairdryer and air conditioner. Almost never used = clothes dryer. Never used = electric space heater. (2022 edit: Sometimes when we think we have shore power we mistakenly run our electric space heaters from the batteries. We do this when shore power fails and we don’t know that it has failed. It is very hard to tell when shore power has failed in our RV because operationally everything is the same. This results in depleting our battery supply in just a few hours.) Extended RV Dry Camping for twelve days on solar
Air Conditioning on Batteries and Solar Test Results
Air Conditioning on Batteries and Solar is very possible, but you have to know the limits of the system. Just because you increase the abilities of the design, it does not mean you are operating without limits.
Updated October 14, 2020, includes edits from 2021 and 2022 as noted
Can you run your RV Air conditioner on Solar and Batteries?
We have the test results. The quick answer is yes you can. We have proved that it is possible. This update includes testing data with some surprises. These surprises are not always encouraging and show how hard this is and why it is this hard.
As I write these observations we have been running our air conditioners from our batteries for a total of five and a half hours over two different days. During monitored tests, we consumed 839 amp-hours of electricity. On average this is 152 amps per hour. This is almost twice the consumption we expected. You might say that we found the limit by pushing as hard as we could. The pedal is all the way to the floor and there ain’t no more.
Running our air conditioners while driving
We first tested running our air conditioners, operating from solar and our batteries while driving, in the middle of the day. The air temperature during the test was between 85 and 95.
The dash air conditioner was not working correctly (we didn’t know that at the time) the dash air conditioner was unable to keep up with the heat gain. The bedroom area in the back of the RV was also hot but we did not run the air conditioner in the back during the test — simply because we couldn’t unless we had started our generator.
Had we been stationary, we would have had a less challenging test for one big reason, we would have covered all our windows to prevent sunlight from going through the glass. We were driving south when we ran our air conditioner from our batteries, this explains how hard the test was. The sunlight was streaming through our four-by-eight-foot windshield and the driver’s three-foot-by-four-foot window for the entire duration of the test.
Since we were driving, our air conditioner had constant airflow and wind moving across the unit. This increased the efficiency of the air conditioner by a small amount. However, given the design of the air conditioner, the airflow did not go through the condenser coils which would have made a big difference by aiding the heat transfer.
Also to make the test hard, (and because I am cheap — even with electricity from my batteries) we waited until the RV was uncomfortably hot before turning on the RV air conditioner from solar and batteries.
We also left our refrigerator on during the test, just as we would have had we been using our RV in normal conditions.
A big problem is the inverter overhead
Our inverter is a Magnum 2812 inverter/converter and the maximum sustained output of the inverter is 2800 watts. Totally we pulled up to 2680 watts per hour during the test. This was a combination of the air conditioner plus the refrigerator and inverter overhead. Converting DC electricity to AC electricity in the inverter counts for 10% of the energy used during the test.
Thus you can blame the inverter for 268 watts of energy per hour consumed at this data point. The refrigerator alone, while cooling consumes more than 266 watts of energy per hour (peaking above 400 watts occasionally). These numbers include static (24 hours a day) inverter overhead of about 23-40 watts). Even when doing nothing our inverter consumes about 23 watts per hour. This is inverter overhead. Something I understood and now that I have experienced it – it is now very real.
This means that producing the energy to run the air conditioner comports with the maximum design draw of the air conditioner which is about 2017 watts per hour will operate at 95 degrees on the high setting. (Energy consumption of air conditioners increases with increasing outside air temperature as illustrated in this table from the Coleman operations manual.)
Air conditioner energy use at different temperatures
According to the above graphic, each increase of five degrees above 95 degrees will result in increased air conditioner power consumption by about 120 watts. The air conditioner manufacturers are careful not to provide the exact numbers for increased energy consumption based on condenser temperature.
Other individual data points (all include inverter overhead)
- Front air conditioner on high – driving – cooling, refrigerator on – cooling = 2350-2680w
- Front air conditioner on high – driving – cooling, refrigerator on- not cooling = 2124-2171w
- Rear air conditioner on high – cooling, refrigerator off = 2050-2086w
- Rear air conditioner on low – cooling, refrigerator off = 1963w
- Refrigerator – cooling two computers and monitor on = 358w
- Refrigerator – cooling one laptop on = 300-353w
- Refrigerator – cooling, nothing else on = 266w-426w
- Rear air conditioner – fan only, refrigerator off = 254-286w
- Refrigerator on – not cooling, everything else off, = 87w
- Nothing on except inverter = 21w
These are individual data points not measurements over a period of time. Also, data points while driving had different conditions than when stationary.
Internet-based False Hope
There is a lot of information available on the internet, that for me created some false hope in terms of how long I could run an air conditioner off my batteries.
Issues associated with operating your air conditioner from battery power
First, I have a very large air conditioner. (15,000 BTU) Second, I tested in a challenging situation. Third, I did not correctly anticipate inverter efficiency. Finally, you don’t just run an air conditioner — you have to run other things in addition to the air conditioner.
I’m going to assume that others stating they can run their air conditioners at numbers well less than my measured 2000+ watts per hour must have smaller air conditioners. They also probably have less space they are trying to cool than I have. Perhaps they also have a different color RV that would reflect more heat (polished silver is best) and maybe they have a better-insulated RV.
I’m also going to assume that others are trying to run their air conditioners in a much less challenging environment. If you want air conditioning at 80 degrees, in the shade, the answer is going to be much different than in the direct sun, at 95 degrees.
I have already addressed my oversight of inverter efficiency in the above analysis of test results.
We did not turn off our other loads, just so that we could run our air conditioner.
One of our future tests will be at night when sleeping — we should be able to go all night long. It depends on how much of our battery charge we use before we go to bed. (edit 2022: This worked great last winter in Key West. In our campground, while dry camping we were the only ones with enough power to operate our air conditioner from our batteries while we were sleeping. Here is a link to the results. How did we live on Solar when at Key West?
Limits to all solar electric systems including our solar array
At first, operating our air conditioner with solar and batteries previously was an incomplete test… we don’t have solar so we did battery tests to determine if the proposed solar would accomplish what we wanted it to do. Obviously, the possible consumption of 2680 watts per hour from the battery cannot be offset by less than 2000 watts of solar.
The inverter overhead associated with the 2680 watts load will still be required with solar. If we could get 2000 watts from solar, we will be able to produce about 2/3 of the consumption. Perhaps this argues for a bigger solar array but I don’t think so. We expect the solar to carry most of the load — not all the load.
Now that we have a fully functional solar array and we knew this before installation, I should point out again that our solar array is almost always oriented in a fashion that inhibits it from performing at or even near laboratory specifications. We limited our expectations with this assumption. We are lucky to extract 75% of the laboratory-specified ratings. Unless your solar array tracks the sun, you will probably have the same result. This is one of the reasons we installed eighteen hundred watts of solar panels but only allocated and anticipated fourteen hundred watts of delivered energy.
Over temperature in your battery/inverter compartment is a real possibility
One of the surprises, other than how much load the air conditioners place on batteries is how hard the inverter was working to convert the DC power into AC power. In the future, we might decide not to run the air conditioners while we are driving, because this puts a large load on the inverter creating heat that we currently don’t have a way to vent.
The maximum temperature we saw in the battery compartment was above 100 degrees. The temperature sensor is about 9 inches off the floor – attached to the battery. Our inverter is attached to the ceiling. This means that the temperature at the inverter level was higher than the temperature sensor. When we saw the temperature rise, we put an end to the test. Heat is not good for inverters or batteries.
Airflow in the battery/inverter compartment
Airflow in the battery compartment is much more restricted than I had thought it was. When the temperature hit 100F in the battery compartment I turned the air conditioner off. This is a large compartment (with lots of junk) and I didn’t think it was this airtight – I guess I was wrong.
The outside temperature when the compartment temperature hit 100 was 95 and we were getting close to Las Vegas. The reason the temperature was rising was that the inverter was making this heat. Remember the 268 watts of inverter overhead, the inverter was converting this waste into heat while making the conversion from DC to AC.
This is going to lead to another modification. Near the inverter, I am going to install a couple of vents that will help prevent the high temperatures. Of course, in the winter, I will need to close the vents to keep everything warm. I am also thinking of a scoop that would provide some ram air cooling to the inverter compartment. This would also need to be closed in the winter. (Edit March 2023: I have yet to install these vents and the location that I have chosen wouldn’t work when driving. So instead, we open our compartment doors to increase the airflow inside the compartments. )
Most obviously we are going to have to figure out why our dash air conditioner is not sufficient and why we needed to turn on the roof air conditioner. I know it is common in big RVs to run the roof air conditioner, but I am not yet ready to accept this as a requirement. (edit 2022: our dash air conditioner was completely nonoperational. During our last visit to Red Bay we got it fixed.)
I started writing this post right after we rewired our circuit breaker panel to enable the test. So, unless something major changes I am going to consider this subject covered.
It is important to measure rather than guess
How do you measure how much energy is coming out of your battery? Check out this article about what I think is the most critical component in an RV electrical system. Battery Monitor
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The critical component for air conditioning from batteries and solar
Air conditioning from batteries and solar would not be possible without adding this one critical component. This component tames the spike that happens when the compressor starts. Here is my link to installing my Micro-Air EasyStart.
This is what we used. We do not get commissions on the links and are provided only to help our friends.
As discussed above, I started testing RV solar and batteries five years ago. I started writing this article in 2020 and some of the comments were from a previous edition released in September 2020. Over the last three years, I have edited this article every year to provide the most up-to-date information available.