Thursday, October 6, 2022


Phantom electrical loads can spoil your boondocking adventure

By Bob Difley
Phantom loads are electrical connections to your batteries that continually draw power, however small.

Loads that are run off the house batteries will not be a problem as they are slight. Since you will be charging your house batteries with solar panels or a wind turbine, generator, or by running your engine to keep up with the drain of boondocking, these phantom loads are inconsequential.

The problem is with those phantom loads connected to your starter battery, such as the dashboard clock radio, or anything else that is powered by the starter battery. Most wind and solar systems do not also charge the starter battery, so you would have to set up a separate solar trickle charger to handle phantom loads on your starter battery if they became a problem.

Investigate what they are and shut them down when boondocking. It won’t matter for a couple of days, but if you are an efficient boondocker and stay out for a long time without starting your main engine, you could end up with a dead starter battery.

You would have to consult your owner’s manual to determine what those phantom electrical loads are. It is also a good idea to check your starter battery’s voltage occasionally to verify that there are no loads sucking juice out of it that you hadn’t discovered.

You can find Bob Difley’s RVing e-books on Amazon Kindle.



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6 months ago

I used these on my neighbor’s 2001 F-150 truck to help eliminate a phantom draw and to track down the issue that kills his battery in two weeks:
Battery Terminal Connector Clamp Quick Release Adjust Disconnect

They are okay for the price, kind of wimpy, I certainly would not use them for a diesel, they are okay for a small truck.

His other truck (Expedition) went dead because although he shut off the switch to the courtesy lamp, so the bulb would not light, having the tailgate/hatch ajar caused the switch to close and it drew enough power to kill the battery after two weeks.

Michael Galvin, PhD
6 months ago

You can just disconnect the chassis battery, with the plug by the accelerator.

David C
6 months ago

This is so true, you can also get a hulkman jump starter. I bought one from Amazon and charge it up and when it came time to get my RV to start from winter storage my battery was flat dead. I even made a point to run my engine once a month for 30 minutes to send a charge and that did not work. Since then I installed a trickle charger. But before that, I grab my hulkman jump starter that was stored in my RV, mind you this was 4 months since I charge this up, hook up to starter battery and first turn of key, engine started. I was very impressed.

6 months ago

To stop phantom loads on my engine battery, I installed a cut-off switch on the engine battery. Totally disconnecting the battery stops the drain.

6 months ago
Reply to  tom

Winnebago has, for at least 2,maybe 3 decades, installed 2 switches on the instrument panel; one to cut-off phantom loads on the engine batt. and two to just in case, boost the engine batt. from the coach batts..

PS: Wet cell batts also loose about 10% of their power per month, whether connected or not. Keep a trickle charger on in storage.