Mercruiser charging

[CampionGuy]

Hi all,
I am new to the forum and have a question that I believe some of you may answer.
3.7l mercruiser w/Alpa 1 leg, 21.5' Campion Discovery both 1988 vintage.

I seemed to lose battery voltage on sea trial when the engine was hot, after cooling (possible battery regeneration?) power was restored but still somewhat weak. After managing to get the boat home and running it on muffs I found that the #1 battery was charging a full 14.88v but #2 was showing only 12.4v I am using a perko battery switch which I previously removed and cleaned all terminals and all connections to a mirror finish as well as the connectors at the batteries. While running I use the "both" selection on the switch. I can't honestly say that this was or wasn't a pre-existing condition as this was the first trip this year. (late I know but surgeries prevailed)

Shouldn't the batteries both be charging while engine running?

Thanx in advance,
Doug

 

[Silvertip]

Re: Mercruiser charging

That's what the switch is for -- yes, they should both charge. You do have a ground cable connecting the negatives on both batteries don't you??? Battery #2 might also be bad and not capable of holding a charge. Have it load tested. Sounds like there's an auto-reset circuit breaker in the system that is tripping.

 

[CampionGuy]

Re: Mercruiser charging

Yeah, battery ground runs from one to the other, a configuration which has been in place since I got it 9 years ago. Batteries are 2 years old and kept outside. Where I live is in temperate rain forest so cold spells rarely get below freezing. But will load test both to be sure.

Doug

Silvertip:
Circuit breaker tripping? You mean the main breaker or am I missing something?