Sunday, May 28, 2023


When plugging in your RV at home, should you unplug shore power while using charger?

Dear Dave,
I keep my camper plugged into a 20-amp outlet when it is in the driveway. Before I leave on a camping trip, I attach a charger to be sure the camper battery is as charged as possible. Should I unplug the shore power while using the charger? —John

Dear John,
This is a common practice with RV owners during storage and when getting ready for an RV trip. Something I stress in my seminars and RV Repair Club live events is to have a qualified electrician install a dedicated line with circuit breaker for your rig.

Typically owners bring their rigs to the driveway and plug into an outlet either outside or inside and think nothing of it. What they don’t see is that most garage outlets are “ganged” or wired to other outlets. All of them are on a 10- to 15-amp circuit breaker. That means there could be a refrigerator, air compressor, or other appliances that are also drawing from that circuit and can overload it. Since you indicated it’s a 20-amp outlet, I hope it is dedicated to just that plug.

To better answer your question, I would like to know what kind of converter/charger your rig has. If it’s a conventional converter, it will sense the battery condition and put a 13.6-volt charge to the batteries until they reach 12.6 volts and then go to a maintenance charge of 13.2 volts. This will keep your batteries charged but not conditioned. That’s because sulfur coats the plates during discharge and needs to have a bulk or conditioning charge of approximately 14.4 volts to break up the sulfation.

What type of aftermarket charger are you using?

Another question is what type of aftermarket charger are you connecting just before using the camper? If it’s a traditional portable charger, then it’s doing nothing more than your standard onboard converter and I would not even use it. If it does have a multistage charger, then I would shut off the main switch at the distribution center and just use that.

A product that I have been using for storage and getting ready to leave is BatteryMINDer®. It throws high impact waves into the system to break up sulfation, which means less gassing and water needed. You can find them here.

Two other things to throw out there is make sure you are not running the roof AC units and refrigerator on that 20-amp circuit. Know your amp draw, as each roof AC can draw up to 14 amps and the refrigerator 8 amps or more. Second, which has nothing to do with the amp draw and charging but is an issue with refrigerators. Make sure the unit is level in the driveway before cooling the absorption refrigerator down. If it’s out of level, it can ruin the cooling unit, which is an article for another day.

 You might also enjoy this from Dave 

Does my RV still need a battery when connected to shore power?

Dear Dave,
I live in Montana. I remove my RV’s dual 12v batteries and bring them inside. Then I plug my trailer into shore power to run a small heater. I discovered that I cannot use my slide function without the batteries hooked up to the system. What is the purpose for wiring it that way? Shouldn’t it be set up to also work off shore power? —Mark, 2019 Northwood Arctic Fox 25W. 

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Dave Solberg
Dave Solberg
Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. He has been in the RV Industry since 1983 and conducts over 15 seminars at RV shows throughout the country.


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Ed W
1 month ago

If you turn off the charging, then what’s left? A large majority of a camper runs off of 12V. Pull the charger and there’s a high probability that the battery will die.

1 month ago

Found out by accident that my slide-outs work fine with no battery if plugged into shore power. After winterising the trailer (it is permanently sited), I went back to check on something and noticed one of the slide-outs wasn’t all the way in. Battery was sitting safely in my garage at home! Plugged in the shore power and hey, voila, slide retracted fine 🙂

Capt. Jim
1 month ago
Reply to  Merv

This was my experience as well. Safe Travels.

1 month ago

Had a isolated 50 amp plug installed on it’s own circuit breaker. Worth the minor cost.

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