www.iFourWinns.com

Any battery experts? I have a couple of 110 AH lead acid batteries and I charge them up each year before I refit them to the boat. After charging, they have always had slightly different residual voltage; 12.79 V and 12.73 V. Neither seems to struggle on the boat if I use them to start the engine.

I also have a dual purpose marine- leisure battery which I keep in the garage ( left over from the last boat, a second battery project that never happened because I changed the boat). The residual voltage after charging is 12.79V, but when charging it the voltage from the charger reaches about 15.2 V. For the other two, it never goes above 14.2V.

Is there something wong with one or more of the batteries, or is it just down to the different construction ?

Graham

No expert here, but everything I know says that a charge rate above 14.2 volts is overcharging. I am suprised your not boiling the battery. You may have lost a cell in the third battery. Even though your residual voltage is 12.79, put a load test to it and see if it holds. My guess is it will fall on its face.

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Jeff

'14 Cruisers 380 Express "Simon Sez"
Merc 8.2 Mag MPI 380
DTS B3X, (x2) Axius Premier


(SOLD)
'08 V318
Merc 350 Mag MPI 300
DTS Seacore, B3 (x2)

Jeff,

Thanks for the advice; I'll test it. Maybe not such a good battery to keep as a spare!

Graham

Are you charging them of a portable (120Vac) the unit in your boat, or off the engine?

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2000 Four Winns 248 Vista (Nice toys, no Air)
2001 Highly Modified Yamaha GP1200R (75+MPH)

All 3 batteries were off the boat and were being charged by a mains powered charger in my garage.

Graham

Sounds like you need to load test the batteries. That more than charging rate, or post-charge voltage is the way to really determine battery strength. Take it by a local automotive place and ask them to check it out. In my area there's a local place called Illinois Battery - they will test batteries for free, heck, they will test a car's charging system as well as battery for free and isolate whether the issue is alternator, regulator, or battery. They sell reconditioned batteries, so this service brings in a lot of local business. Perhaps there's a similar place by you?

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2007 Horizon 200
4.3L GXi/ SX 225 HP