My RV's Generator Only Starts When The RV Is Plugged In, What's The Problem?

by Dana
(NM, USA)

I recently bought a 97 PaceArrow. When the owner was showing it to me, he started the engine, pushed the button for the generator and it started right up.

A couple weeks later when I went to pick up the coach, the generator wouldn't start. The fridge wouldn't come on either. They plugged the coach into the house using an extension cord, and then everything worked. The generator would start and the fridge worked.

I asked him when he last topped off the water in the auxiliary batteries and he said, "they need water?" They are about three years old. The water was quite low, so they filled it up with tap water. Now it shows a full charge, but the generator still won't start. Just get click-click-click-click. Do you think it's just the auxiliary batteries that need to be replaced or something else wrong? They power the house lights fine. Thank you!

ANSWER Greetings Dana thanks for submitting your question on our Ask An RV Question Page.

My gut instinct tells me that you need to replace the house batteries as they are not strong enough to start the generator. If the generator still starts with the RV plugged in, then that tells me that the starting problem is not due to generator.

Even though you say that the 12 volt interior lights are working off of the battery; that does not mean that the batteries are providing enough juice to start the generator. One thing you mentioned in your question disturbed me "I asked him when he last topped off the water in the auxiliary batteries and he said, "they need water?" They are about three years old. The water was quite low, so they filled it up with tap water." You should only use Distilled water in the batteries, never tap water. Tap water has minerals and impurities that can damage a battery.

The only way to determine if you need new batteries is to run a few tests. I am going to refer you to the answer I gave to this question Our RV Interior Lights Only Work When We Are Plugged In Or Generator Is Running. In the answer I gave I outlined some troubleshooting steps they needed to perform to find out what was wrong with their electrical system. You should start at step 3 on that page.

Again I am pretty sure that your batteries are the problem. It is just a good practice to eliminate every other cause before going out and purchasing new batteries.

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Happy RVing

RVing Al