Do RV Batteries Charge When Plugged Into Shore Power?

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  • Post last modified:September 9, 2020

What is the best way to charge RV batteries? Do batteries charge when plugged into shore power? We have researched this topic and have answers for you about charging RV batteries.

When an RV plugs in to shore power, two things happen. First, the RV has an AC power supply for any electrical devices that require AC power. Second, the RV’s DC batteries in the battery bank will charge.

There is a lot more to this topic than just what happens when you plug into shore power. How does shore power charge the batteries, and how do you keep them charged? How long do they stay charged? Should you disconnect the batteries? Do you even need batteries? Keep reading for answers to all of these questions and a few more.

A travel trailer with chairs set up for camping and parked near a lake with a scenic view, Do RV Batteries Charge When Plugged Into Shore Power?

How Do You Charge Batteries With Shore Power?

Shore power is an AC power source. AC stands for alternating current. Like most other vehicles, your RV’s systems are primarily DC, which stands for direct current. Many RVs will have both AC and DC outlets and have inverters and converters to change between AC and DC power. 

The batteries in your RV’s battery bank are DC. When you plug your RV into AC shore power, the RV’s converter transforms the alternating electrical current sent to the batteries into direct current. As long as all of these systems are working, your batteries will charge while plugged into shore power.

How Do I Keep My RV Battery Charged?

If you won’t be using your RV for a while, it’s essential to keep your batteries charged while in storage. Keeping the batteries charged will prolong the batteries’ life. There are a few factors that will affect whether or not your battery bank stays charged.

The ambient temperature will affect how quickly your batteries discharge while in storage. The batteries will drain quicker in hotter temperatures than they will in cold temperatures.

You can also help your batteries maintain their charge in storage by disconnecting all systems that would typically draw power from the batteries. Disconnecting appliances and other things that utilize your DC batteries will ensure that these items can’t drain your batteries by accident.

An even easier method than unplugging your appliances is to disconnect your batteries. It is essential to check your batteries’ water levels to ensure they won’t run dry and become damaged. It would be best if you also kept your batteries clean and free of corrosive buildup. You should check on your RV batteries once per month while in storage, if possible.

Lastly, you can install solar panels. Solar panels are DC power sources and can feed power directly into your batteries. You can use the solar panels to trickle charge your batteries. Trickle charging is where you only supply enough power to replenish what has drained while sitting in storage.

How Long Will RV Battery Stay Charged?

If you aren’t going to plug into an external power source that keeps your batteries charged, it’s essential to know how long your batteries will last. Under normal use conditions, one 12V battery will last 2 to 3 days. You may be able to get up to a week before needing to charge your batteries, though.

Many factors affect how quickly you will drain your battery bank. Some of these factors are:

  • The number of batteries in your battery bank
  • The condition of the batteries in your battery bank
  • How conservatively you use power in your RV
  • How efficient the appliances and systems are in your RV
  • Temperature and humidity levels

Check out our post on the best batteries for going off-grid.

Should I Disconnect My RV Battery When Plugged In?

Your RV’s power system is designed to charge the batteries while plugged into shore power and not damage them in the process. You should not need to disconnect your batteries while connected to shore power. Keeping your RV batteries charging via shore power prevents them from draining too much while not in use.

It is also important to note that not all of your RV systems can run on AC power. Unless you have an inverter to transform AC power into DC power, these DC systems will not work without your battery bank connected to your RV’s power system.

However, if your RV is equipped with an inverter, you could disconnect your batteries if you will not use them for a very long time. For example, if you park somewhere for a month and have a shore power hookup and an inverter, you could disconnect your battery bank during this time. There is a downside to doing this, though. If the power grid goes down, your RV will not switch over to its backup systems automatically.

Additionally, your batteries will drain little by little while disconnected. If you are parked somewhere for a long time and decide to disconnect your batteries, consider using a trickle charger to keep your batteries ready for action when you need them.

Can I Run My RV Without A Battery?

Without a functioning battery bank, your RV will still be capable of driving around, but will any of its systems still work? Some appliances run on propane, so do you even need batteries?

While some RV appliances can run on propane, they still have 12V control boards that require DC power to operate. Even though these appliances use propane to run, they need electricity to start running.

It is possible to rework your RV to be fully functional without a battery. To do this, you need an inverter, and you also need to be plugged into an AC power source to have power. Most people would agree that doing this largely defeats the purpose of having a powered RV, though, because the power systems for the living space of your RV will not work when the RV is not connected to an alternative power source.

Will My Slide-Out Work Without Battery Power?

If your batteries become fully drained when your slide-outs are out, is there a way to get them back in? Thankfully, your RV is designed to use multiple power sources for moving your slide-outs. 

Most slide-outs are capable of using both AC and DC power. So, if your batteries aren’t working, you can use the AC power supplied by shore power to run your slide-outs. Subsequently, you can use a generator to create the power to run your slide-outs.

If you don’t have any power source, some RVs have slide-outs that are operated manually. With the use of a specific tool, called a T handle, you can manually move your slide-outs.

How Do I Know If My Deep Cycle Battery Is Bad?

When your battery power stops working, there are a few possible culprits. It could be that your batteries are bad and need replacement, or there could be another problem with your electrical system.

Follow these steps to figure out if your deep cycle batteries are bad.

  1. Do a visual inspection of the batteries. Look for anything that is visibly damaged or corroded. Clean up components that have corrosion, and replace any damaged components.
  2. Test the batteries. Make sure to charge the battery fully before testing. While this testing process will be the same for most batteries, check the battery manufacturer’s instructions for testing your specific batteries.
    1. Take a hydrometer reading by squeezing the bulb and releasing it to suck up some electrolyte. Make sure that the reading meets the manufacturer’s minimum spec requirements.
    2. Take a voltage reading, and compare it to the manufacturer’s specifications for a fully charged battery.
  3. If the battery does not have an adequate voltage or hydrometer reading, you should replace the battery. Shop around for a suitable replacement battery to make sure that they last a long time and are appropriate for your RV.

There are other issues aside from bad batteries that could cause problems in your DC power system. You may have chaffed or broken wiring somewhere in your RV, or you may have a bad converter or inverter. Take your RV to a qualified RV technician to troubleshoot your electrical system for these other problems.

Conclusion

RV batteries are an essential component if you want to get the most out of your RV. Batteries need to be connected for all of the systems to function in an RV unless you have an inverter and a constant source providing AC power. Disconnecting your batteries from the RV’s systems can help prolong your batteries’ lives while in storage. Using a trickle charger can ensure that they stay fully charged during that time without being overcharged. When your RV batteries go bad, shop around for a good replacement.

 

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