Can I Run My RV AC Unit On Lithium Battery Power?

It never fails that when the temperature in your RV increases, so do the attitudes and crankiness. Being inside a hot RV can be super uncomfortable and make you want to pack up and go home. More and more RVers are upgrading the battery banks in their RVs to lithium batteries, which are more powerful than standard lead-acid batteries. But can they power an RV AC unit and keep you cool in the heat of summer?

Let’s find out!

Can You Run Your RV AC Unit On Batteries?

The short answer is yes. With the proper equipment and enough batteries, you can run your RV AC unit on batteries. In addition to the lithium batteries, you’ll need an inverter to invert the DC battery power into AC power for most air conditioning units.

While many RV electrical components run off 12 volt DC power, some larger appliances require AC power, like an RV AC unit. A quick point of clarification, the “AC” in “AC unit” stands for “air conditioning.” The “AC” in “AC power” stands for “alternating current.” 

For smaller RVs, a growing trend is 12V air conditioners. These tend to be much more efficient and can easily run on batteries. Custom-designed “mini-split” units also tend to be much more efficient than traditional RV air conditioners. Many people that want to run their air conditioning on batteries opt for this more efficient custom design option. 

In addition to needing an inverter for 120V AC units, you’ll also want to invest in a soft start kit or an EasyStart. When your AC compressor first kicks on, it draws 4-8 times more current than is needed to run the compressor. This is called “surge current.” A soft start kit helps improve the startup efficiency of the AC compressor and reduces the power draw on your batteries.

While running your RV AC unit off of your batteries is possible, there are a few more things to keep in mind. Even larger battery banks won’t be able to sustain an RV AC unit for long due to their large power draws. This makes it difficult to run them for extended periods of time.

However, running your RV AC unit on lead-acid batteries was virtually impossible. So the fact that it can be done with lithium batteries in itself is a gamechanger!

For How Long Will A Lithium Battery Run Your RV AC Unit?

How long a lithium battery can run your AC depends on your battery or battery bank size and the size of your RV AC unit. 

For example, a 100 Ah lithium battery will power a typical 15,000 BTU RV AC unit for about 30 minutes. If you’re RVing in hot weather, running your AC for 30 minutes likely won’t do much to increase your comfort. However, if you had a bank of eight 100 Ah batteries, it would run for about four hours. This may be just enough time to beat the heat in the hottest part of the day.

A 12V air conditioner is much more efficient because it does not require an inverter and typically will run for a few hours on one battery. However, these are much smaller units. Similarly, custom mini-split designs tend to be much more efficient and can run longer than traditional RV roof mount units. Both options can typically run an AC overnight without much problem on a four or six Battle Born battery bank.  

It’s also important to remember that running your AC will likely completely drain your battery bank. If you rely on solar power to charge your batteries and you drain your batteries by the end of the day, you’ll have to wait until the sun comes up the next day to recharge them. Keep this in mind if you’re relying on your batteries to power essentials like residential fridges or CPAP machines overnight.

If you have a hybrid inverter that combines generator power with solar power, you can often prolong the energy stored in your battery bank for an even longer run time.

Is It Expensive To Run Your RV AC Unit Off Batteries?

If you look at the system you would need to run your RV AC unit for a reasonable amount of time, it would not be a cheap system. So yes, running your RV AC off batteries can be expensive.

However, the decision to upgrade to RV lithium batteries usually isn’t solely based on the need for air conditioning. If air conditioning is something that you want to be able to do, you will need to factor that into your build and it may involve additional costs.

Components Needed

A large chunk of the expenses to run your AC off batteries are the batteries themselves. A typical 100 Ah lithium battery costs $800-$1000 per battery. It’s easy to see how the costs can quickly add up the longer you want to use your AC unit.

No matter how long you want to run your AC unit, you’ll need an inverter. Victron makes the MultiPlus inverter and charger combination. This is a popular option among many RVers who choose the 3,000 VA* version, which typically costs around $1300.

*A note on Victron Multiplus inverters: Victron Rates its inverters in VA or Volt-Amps. This is an accurate measurement of power in AC appliances but does not directly convert to watts. Depending on the inductance of the load the max wattage will vary. With an inductive load like an air conditioner expect the inverter to provide a max continuous wattage of 2,400 watts. Also, the 5000VA model provides a max continuous wattage of 4,000 watts.

With larger RV AC units, you might need a soft start assist as well. MicroAir makes the EasyStart soft start which typically costs around $300. 

Investing in a 12V RV air conditioner may be worth it if air conditioning is essential. Unfortunately, this option is also expensive since these units cost much more than a traditional RV air conditioner.

Building a Custom System for Running Your RV AC Unit

Many Battle Born customers that want to run AC opt for a custom system. A small residential mini-split unit is a good middle-ground for many people, providing high efficiency and reasonable cost. Mid-sized Battle Born Battery banks work well with these units.  

If you’re expecting to camp in extreme temps and run your RV AC unit on batteries alone 24/7, you will likely have to build a very robust system. A system capable of doing this could cost upwards of $20,000. But remember, that system would also be able to power additional things outside of the AC.

Many RVers find that they can use their AC for an hour or two. But ultimately, they rely on a combination of solar power and a generator if they need to run their AC for prolonged periods.

What Wattage Do You Need To Run Your RV AC Unit?

The wattage needed to run your RV AC unit depends on how big the unit is. Typically, the startup wattage required ranges from about 1,000 watts on a 5,000 BTU AC unit to 3,500 watts on a 15,000 BTU unit. 

Once your AC unit is running, it requires much less power. On average, a 5,000 BTU unit needs 300-450 watts, while a 15,000 BTU unit needs about 1,500 watts.

12V air conditioners are much smaller and typically run between 300 and 600 watts. These, however, do not require an inverter and can be connected directly to the battery system because they run on DC power.

How To Get The Most Out Of Your RV AC Unit

Whether you’re powering your RV AC unit with batteries or shore power, you want to get the most out of it. Let’s take a look at a few tips to keep your RV cool!

Park In The Shade

The shade will be your best friend when it comes to keeping your RV cool. Parking your RV in the shade or in a way that limits your exposure to the sun will keep your interior temperature down. The cooler your RV is, the less you have to run your AC.

However, if you’re relying on solar power to offset the power draw, you might instead opt for full sunshine.

Insulate Your Windows

While large massive windows on your RV are great for enjoying beautiful landscapes, they’re your AC’s worst enemy. The culprit here is the greenhouse effect. Essentially, the sun’s rays heat the interior of your RV, and the heat gets trapped by the windows.

Using products like Reflectix can help keep heat from the sun out of your RV. You can cut the Reflectix to fit your windows and also use window shades or curtains to provide further insulation from the heat.

Cool Individual Rooms

While having extra rooms and space in your RV is nice, you likely don’t use them all at the same time. Cooling an area that you’re not using is a waste. You can close the vents in those spaces to help pump more cool air into the rooms you’re using.

Many RV ACs come with a dump feature that will dump loads of air into the room where the AC sits. This will feed little, if any, air into the air duct system and will cause unused rooms to heat up. Keep doors closed or hang blankets to prevent cool air from leaving the spaces that you’re using.

When you do this, take note of the temperature sensor locations in your RV.

Clean Your Filters

The more you use your AC unit, the more you should clean your filters. The filters block debris from entering your RV AC unit, and the more these filters are clogged, the harder your AC unit will need to work. 

If you are in an environment where your AC runs constantly, you will likely need to clean your filters once every couple of weeks or so. Alternatively, if you use your RV AC sparingly, you can get away with cleaning your filters less frequently. If dust is accumulating on the AC where the filters sit, the filters are likely due for a cleaning or replacement.

Is Upgrading To Lithium Batteries Worth The Cost?

Upgrading to lithium batteries is definitely worth the cost. Even if you spend the bulk of your camping in campgrounds or connected to shore power, you will realize the benefit from lithium in that they last so much longer and will not require replacement. 

Upgrading your battery bank will allow you to camp off the grid or stay overnight with all the power you need to cook, watch TV, and yes, even run the RV AC unit some. They pack a tremendous punch for their size and will last years longer than any other type of battery used in RVs. 

Despite the high upfront cost, lithium batteries are the most cost-effective battery option in the long run if you’re looking to use your RV regularly while not connected to shore power.

Conclusion

Running power-hungry appliances like an RV AC unit requires an incredible amount of energy. Despite being extremely powerful batteries, smaller lithium battery banks are often no match for traditional RV AC energy monsters.

Overall it is possible to run your RV AC unit on lithium batteries, and many of our Battle Born customers do!