Another battery charging question
I have a boat which I occasionally use for overnight camping.
Yesterday I put the boat in the water after sitting on a lift for a couple of months. Batteries good when last used. Battery cutoff switch used so no drain except for a rare bilge pump activation.
Anyway, one battery fired the motor immediately. The other would not turn it over. I ran the boat with the switch on ALL for about an hour which will send a charge to both batteries .
Today I pulled both batteries to check water level and give them a top off charge. Batteries are " no maintenance " although you can add water. They were both at about same level ( above plates ) and required very little water. Terminals on both were clean.
Battery #1 which cranked the motor initially measured 12.65V. Battery #2 which did not crank the motor initially to my surprise measured 12.40V. I figured it was way low. Battery #1 is the one hooked to the bilge pump.
When I connected the charger to battery 2 water started bubbling out of the top, but just on one side. Battery is dated 4/12.
I am thinking there must be a short of something in that battery ( #2). I don't think running the motor for one hour would have charged it to 12.4V if it were dead.
I know this is not my TT battery but same principle applies I guess. Can battery #2 show 12.4V and still be bad under load due to a short?
Opinions please...
Yesterday I put the boat in the water after sitting on a lift for a couple of months. Batteries good when last used. Battery cutoff switch used so no drain except for a rare bilge pump activation.
Anyway, one battery fired the motor immediately. The other would not turn it over. I ran the boat with the switch on ALL for about an hour which will send a charge to both batteries .
Today I pulled both batteries to check water level and give them a top off charge. Batteries are " no maintenance " although you can add water. They were both at about same level ( above plates ) and required very little water. Terminals on both were clean.
Battery #1 which cranked the motor initially measured 12.65V. Battery #2 which did not crank the motor initially to my surprise measured 12.40V. I figured it was way low. Battery #1 is the one hooked to the bilge pump.
When I connected the charger to battery 2 water started bubbling out of the top, but just on one side. Battery is dated 4/12.
I am thinking there must be a short of something in that battery ( #2). I don't think running the motor for one hour would have charged it to 12.4V if it were dead.
I know this is not my TT battery but same principle applies I guess. Can battery #2 show 12.4V and still be bad under load due to a short?
Opinions please...
