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Old 03-23-2016, 10:28 AM   #16
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City: Coastal SC
Country: USA
Vessel Model: Viking 65 CP MY (run at trawler speeds !)
Join Date: Jul 2015
Posts: 388
Originally Posted by Rogerh View Post
Yes, sounds like it is being boiled out by the charger. This is often not the charger that is the problem though. It can be caused by one of the batteries connected to the charger having a shorted or weak cell. I would turn charger off for a few hours and then measure battery voltage, should be about 12.4 volts. Then hit thruster (assuming the batteries are for the thruster) for 5 seconds or so. Check voltage again and if it is down by more than two tenths of a volt I would suspect battery replacement is due. In my experience overcharging is most of the time caused by a defective cell.
Just a note that I keep forgetting to check the battery voltages but will try soon. There are two 8D batteries with West Marine stickers, less than two years old as I recall. The bow thruster system is it's own separate system....the two batteries, a dedicated charger for just those two batteries....wires going to the port/starboard joystick and the charger from one of the ac circuit breakers. Charger to the batteries, batteries to bow thruster control.

In feeling the cases there is no excess heat and there seems to be plenty of water in the cell at the puddle. I'm wondering if previous owner didn't overfill that cell. Anyhoo, will check voltages soon as I can remember (not on the boat that often this time of year)

Guess I need some Arm and Hammer to neutralize the acid before wiping it up, huh..
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