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Can Summer Heat Kill RV batteries? Yes! Here’s What to Do.

Published on August 3rd, 2023 by Dave Helgeson

Stuck in a campground because you can’t recharge dead RV batteries? Are you having problems charging your house batteries due to summer heat?  If so, here’s how to recharge dead RV batteries, and prevent the problem any time of year.

How and why summer heat can kill RV batteries.

Many RVers are reporting problems keeping RV batteries charged during this summer’s heat waves. Are you one of them?

Here is what experts have to say about how summer heat affects vehicle batteries.

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Excessive heat shortens battery life because it accelerates corrosion and causes battery fluid to evaporate, damaging the internal grids. For every 15 degrees above the operating temperature of 77℉, the battery capacity increases but cuts the lifespan in half.

Crown Battery

And another vehicle battery expert shares what happens to RV batteries when you camp in hot temperatures.

Studies show that warm weather increases the heat under the hood and consequently doubles the chances of battery failure. This is probably why it’s not uncommon to see many RVs stuck on the roadside in summer.

Life Line Batteries
6V AGM deep cycle RV batteries. (Image: dlaughlin, iRV2 Forums Member)
6V AGM deep cycle RV batteries. (Image: dlaughlin, iRV2 Forums Member)

Routine RV battery maintenance keeps RV batteries happy in summer.

If you don’t want to get stuck on the highway, don’t skip RV battery maintenance, especially in summer. Make time for keeping battery terminals clean, in a good state of charge, properly anchored, terminals tightened, cells topped off with distilled water, etc.

What if your RV batteries don’t hold a charge?

If your batteries are over two years old and have problems taking and holding a charge, have them load tested. Load testing determines your battery’s ability to be charged along with being able store and deliver the power they are rated for. Load tests can be performed at most any auto parts store or automotive battery distributor. If a charged battery fails a load test it is time for a replacement.

How to Keep your RV Batteries Charged.

Once you have determined your RV batteries are good, you need a method to fully charge them and keep them charged. 

Plug into conventional shore power.

Do you have access to shore power? Is your RV is equipped with a multistage converter / charger? The easiest thing is to plug your RV into shore power letting the converter / charger charge your house batteries.

Motorhome start batteries can be charged with a conventional automotive charger. If you won’t be driving much due to the summer heat, consider connecting your start battery to a battery maintainer (i.e. a Battery Tender) to maintain a charge

Can you recharge dead RV batteries without shore power?

Yes! If you lack access to shore power, no worries. Below are nine helpful ways to recharge dead RV house batteries. Several of these methods can also be utilized to provide sufficient power to retract slide outs, power jacks, etc..

Here’s how to get on the road when your house batteries aren’t up to the task due to summer heat.

Use the alternator in your tow vehicle or motorhome

Your other vehicle can supply the voltage needed to charge your house batteries. To gain efficiency, consider installing a DC to DC charger. This device “conditions” the power coming from the alternator for optimum charging.

Summer heat - maximize battery charging
DC to DC Charger. (Image: Redarc)

A Car Generator can recharge dead RV batteries too.

This device hooks directly to the start battery of your tow vehicle or motorhome. Then it inverts 12-volt power from the battery and vehicle alternator into 120-volts (i.e. shore power). Now just plug your RVs shore power cord into the outlet on the car charger allowing the converter / charger in your RV to charge your house batteries.

Hybrid trucks can also recharge your RV batteries.

Many hybrid tow vehicles entering the market today contain 120-volt electrical outlets. These outlets allow the owner to power any number of 120-volt items including towable RVs.

Many RVers have discovered electric trucks can power their RV when dry camping. In turn, they charge the house batteries via the converter / charger.

Recharge dead RV batteries with a portable or built-in gas generator.

Both built in RV generators and portable gas generators produce 120-volts. This can be used to power the converter /charger in your RV to charge the house batteries.

Many portable generators also offer a 12-volt outlet and charging cable that can be attached to any automotive type battery, be it a start battery or house battery.

Built-in RV generators or portable gas generators are a great option for directly charging house batteries when the converter / charger fails in the RV.

Portable gas generator. (Image: @Edd505, iRV2 Forums member)
Portable gas generator. (Image: @Edd505, iRV2 Forums member)

Use solar power to recharge dead RV batteries.

If your RV doesn’t have an onboard solar system, you may want to give portable solar panels a try, like new the E.Flex from Renogy.

Portable solar panels are a quick and easy way to obtain the power needed to charge your house batteries during summer heat waves.

A portable power station can recharge house batteries.

These devices are often referred to as a solar or electric generator. Portable power stations, like a Jackery or Bluetti, can serve as a short term alternative to power your RV when the house batteries have been flattened by summer heat.

Jackery portable charging station in RV basement. (Image: @Ottosails, iRV2 Forums Member)
Portable battery stations can supply 12-volt power for slide-outs and jacks when RV house batteries fail. (Image: @Ottosails, iRV2 Forums Member)

Want more ways to recharge dead RV batteries in summer heatwaves? These unconventional methods can also do the job.  

Wind power.

Small wind turbines can also be used to generate power to charge your house batteries. RV wind turbines are typically more affordable than conventional solar power. They are also more environmentally friendly than gas generators.

Water turbine.

Just like using wind to generate power to charge your house batteries, flowing water can also be utilized when camping near a fast-flowing stream or river. Here’s a video showing how to make a $50 DIY water turbine.

What better way to beat the summer heat than to be camping by a mountain stream and generating power to charge your house batteries at the same time!

Fuel cells.

This unique technology uses a chemical reaction rather than combustion to turn a fuel source (propane, hydrogen, etc.) directly into electrical energy. NASA has been utilizing fuel cell technology for years. The technology is now becoming available for RVers looking for an alternative source of off-grid power. Learn more about fuel cells for RVs here.

Now you know how to keep RV batteries charged (in summer and beyond).

Hopefully this short tutorial on charging RV batteries during summer heat provides you with the knowledge to assure your batteries are healthy. The host of other methods to keep your batteries charged can work if they don’t hold a charge.

Stay cool, stay safe and enjoy your summer RV travels.

This post may contain affiliate links or mention our own products, please check out our disclosure policy here.

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