Battery Famine Or In This Case Feast

[Bill Sonntag]

Battery Famine or Feast

I used the web board site search function and did not find an answer to my current question, so here goes.

My Universal M-25XPB is overcharging my two batteries dropping the fluid level all too quickly. One battery is a 24 series cranking and one a 27 series house battery both lead acid wet cell type. Boat is equipped with standard isolator/selector switch, Off, 1, 2, Both, position. I’m switching back & forth, watching carefully, topping off with distilled water when needed. And yes, the cockpit locker position for the batteries gets hot in the summer.

The engine has the standard 12VDC 51A alternator. There should be a built-in voltage regulator/diode to prevent this - is it not working or do I need to add one, if so how?

Thanks in advance for any thoughts.

Bill Sonntag
SURPRISE
CD31

[Boyd]

Use a simple multimeter and check the charging voltage. It should be around 14.4volts. I suspect its running much higher. I absence of a multimeter you can take it to a shop and have them bench it.

Boyd
s/v Tern
CD30 MkII
Fort Lauderdale, Fla.

[Russell]

Have you checked the voltage with a digital multimeter while the altinator is charging? Sure sounds like the regulator isnt doing its job, I suspect the voltage is high and causing the batteries to boil.