Should I Disconnect My RV Battery When Plugged In?

Should I Disconnect My RV Battery When Plugged In?

By Renogy marketing team
Renogy marketing team
renogys blog Feb 9th 2023

Every recreational vehicle runs off its house batteries when the RV isn't plugged into shore power or a generator. The batteries play an extremely important role in an enjoyable RV experience.

RV house batteries provide power to various devices in your recreational vehicle. Without them, all these features will be out of commission – from the refrigerator and furnace to the water heater and lights, not to mention stabilizer or leveling jacks, slide-outs, water pumps, and so much more. RV owners must look after their batteries, such as ensuring they are always adequately charged; otherwise, you risk being stranded due to a situation like being unable to retract the awning or slide out.

How to charge your RV house batteries? You may learn more in this article- Effectively Charge Your RV Batteries While Driving.

RV batteries are notorious for draining when not in use. Let's cover some of the more common ways to ensure you take care of your RV house batteries and answer some of the more common questions we receive. 

Table of contents:

Is it bad to leave your RV plugged in all the time?

In short, no, not usually. Thanks to modern smart chargers that come built-in.

Depending on the age of your RV (and no, it doesn't matter whether it's a travel trailer, fifth wheel, or motorhome), the majority of RVs for the last decade or so come with an integrated converter installed that handles both power distribution as well as taking the Alternating Current (AC) you get from shore power or a generator, and converting it into the 12V Direct Current (DC) that the batteries need to charge. 

This device also monitors and controls the power being sent to the batteries to help protect them against overcharging – a potential hazard that can lead to a seriously decreased life cycle for your expensive batteries.

It's best to read the manual that came with your RV or look the model number up for your power distribution panel to see if it has a built-in converter and, preferably with a float mode. If it doesn't, don't worry; we'll discuss some workarounds to ensure that you don't find out your batteries are dead the next time you pick up your RV from storage.

Does the RV battery charge when plugged into shore power?

Yes, under a couple of conditions.

The first is simple: is the battery disconnect switch (usually located very close to the battery, either in a compartment or next to the battery) set to "off?" If the disconnect is off, then no amount of head scratching will help the batteries take a charge. Until you turn the disconnect switch, that is. You'd be amazed at how often RVs get brought in to dealerships for this simple problem. Frequently the issue is that the RV owners are new or didn't even realize there was an in-line disconnect that needed to be considered. 

Next: is your RV receiving enough shore power to handle all of the power requirements and still have enough left over to charge the batteries?

For example, suppose you have a small 1500 Watt generator running your RV, and the air conditioning is cranked up in August while your niece is using a hairdryer for an hour. In that case, there isn't enough power left over for the converter to send to the batteries.

Luckily, the converters we have nowadays are automatic. It takes no effort on your part to redirect power to the batteries when there is a break in power draw.

Will an RV converter work without a battery?

This one is still a hotly debated topic online. The easiest way to find out is to plug your RV into shore power, turn on some lights, water pumps, and other twelve-volt systems and then turn off the battery disconnect switch that we mentioned earlier.

What you'll find is that nearly everything still works fine. So no, you don't need to have a battery installed to use most of your 12V systems.

There is a caveat to that statement: motors with extremely high 12V current demands, such as slide-outs, don't always function without a battery being installed. The reason is that some motors require more current than a typical power convert can deliver at once. The battery, on the other hand, is designed to output power in a larger dose.

Plenty of RV slide-outs can function without a battery. If yours can't, it will typically be listed in the documentation that came with your rig or even via a sticker somewhere near the switch to operate the slide-outs. 

How to Properly Use an RV Battery Disconnect Switch

Also known as: What is this thing, and when should I use it?

An RV battery disconnect switch is an essential feature for any vehicle with a house battery. Performing a single action (usually a twist) allows you to easily and quickly disconnect the main RV circuit from the battery, protecting not only the battery but also other electrical components of your RV.

This switch is typically located in close proximity to the battery itself, either in its compartment or in a nearby maintenance bay. This switch is often overlooked or even forgotten, buried behind stacks of gear inside a storage bay. 

Battery disconnect switch

Batteries have the unfortunate tendency to slowly discharge over time, even if the appliances they're attached to are turned off. While turned off, electrical appliances still draw tiny amounts of energy passively in preparation for startups. Wiring itself also drains power slowly. This type of energy loss drains at least some charge from your battery and can ultimately result in a dead battery precisely when you don't expect (or need) it.

When to use an RV battery disconnect

Understanding when to use an RV battery disconnect is necessary if you own an RV. When dealing with electronics, you should always take the necessary safety precautions, so you don't cause any damage or risk injury.

You're doing any electrical or appliance maintenance

If you're taking the time to work on your RV, whether it's replacing a light fixture or servicing your water pump, be sure to pull the fuse for the circuit, but also consider using the battery disconnect. Not only will this protect you in case of an electrical accident, it can also help prevent costly issues down the road. This relatively simple precautionary measure is crucial for the safe and efficient maintenance of your RV.

Your RV is going into storage without shore power

If you're not going to be using your RV for more than a week or two and don't have the option of plugging it into shore power (even a standard 15A household circuit is plenty to keep the batteries ready), you need to disconnect the batteries. This will minimize the current loss caused by excess runs of wire and appliance trickle.

You are plugged into a 7-Pin receptacle on your tow vehicle

If your RV has a 7-pin connection to your tow vehicle, that means that one of the pins provides charging power for your RV house battery.

This awesome feature helps recharge your house batteries on trips, so you have full batteries when you arrive. However, it can also cause a headache.

If you leave your RV plugged into your tow vehicle for an extended period (hours) without the tow vehicle running, it can drain the battery from the vehicle to charge the batteries on the RV.

Some vehicles turn the power off to that pin automatically when the ignition isn't on. Older ones often don't have that function. I've had to jump my truck off my RV batteries before. Definitely, something I'd rather not relive. 

What if your RV doesn't have a built-in float charger?

 

As mentioned above, some RVs, especially older ones or cheaper ones, might not have a way to keep their batteries float-charged, especially while they're in storage.

Luckily, there are a few easy aftermarket solutions that are incredibly easy to use. Renogy has a few affordable optionssuch as PWM charge controllers, DC to DC chargers, to maintain your batteries using a small solar system.

This is especially helpful when you put your RV in storage and don't have access to shore power. You just put out a small solar panel and hook the alligator clips up to your house battery and show back up to a charged battery. This will help extend the life of your battery as well as make things more convenient all around.

In Summary

For RV owners, deciding whether to leave your batteries connected while plugged into shore power formerly posed something of a problem. Older technologies could make it difficult to keep your house batteries healthy and ready for trips.

However, advancements in RV battery technology now ensure that it's an easy decision! Renogy's deep cycle batteries are designed with low self-discharge rates, meaning that when they are left connected, they'll experience minimal power bleed.

This makes maintenance simple and hassle-free-- a benefit especially evident when returning from a long period away from your RV. Check out Renogy's selection of modern 12V deep cycle batteries and solutions today to enjoy all the convenience of RV ownership without sacrificing battery quality!

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