Community Forums

monaco t · 09-23-2018, 11:09 AM

Yesterday I went to the RV for an inspection. I tried to start the generator to charge the house batteries. It would not crank after several attempts; the panel showed a voltage of 7 or so. Put a multimeter on each of the 6 volt batteries and they all 4 read around 3.3v. I checked a couple of other unrelated things and when I returned to the panel it showed 11.9 V. The generator immediately started and the batteries were recharged.

What could have caused this weird scenario wherein the batteries" came back to life?"

OLYLEN · 09-23-2018, 11:38 AM

Sounds like either a terminal or ground problem. Clean terminals AND ground points to frame.

LEN

twinboat · 09-23-2018, 11:40 AM

Did you happen to start the main engine ?

How long did you run the generator to recharge the batteries ? At a low voltage it will take 3 to 4 hours to get them charged.

Skip426 · 09-23-2018, 11:43 AM

When you have the cables off for cleaning , recheck every battery .

Take a photo before you remove cables .

8.3Oilbuner · 09-23-2018, 11:45 AM

Good morning Monaco t; Sometimes batteries can form bubbles on the plates in the battery. Can't remember why. The bubbles can reduce the surface area of the plates so the acid can't cause the chemical reaction needed to produce the voltage and capacity of the battery. The draw on the batteries when you tried to start the gen. could have caused the batteries to kind of wake up from a none use state. This is why in a shot period of time the voltage changed. Next time before you try to start something like the gen., pull the battery caps and look down into the well to see if there are a large amount of bubbles on the plates. I also would check the specific gravity of the cells to make sure they are healthy. I have seen this before, so it comes to mind. Lots of other owners here have more battery experience than I do so I could be way out in left field for an explanation. This come to mind when I read your post.