Charging Problem

[OxMo]

I have three batteries, 2 for 24v trolling motor, one 12v for starting. When charging, with an on-board charger, one of the batteries for the trolling motor does not indicate a full charge as indicated by the row of lights on the charger. But, when I remove the battery and put it on a stand-alone charger, it checks out ok. Also, with this particular battery, there was a lot of corrosion at the negative terminal (lots of green fuzz). I cleaned it up, using baking soda water and reinstalled to the onboard charger. Same result: Not a full charge on the same battery. The charger is about a year old. Should I be suspecting that as the problem, or is it really the battery? I have not checked the wiring under the deck (pontoon boat) as all connections were soldered. The batteries are a year old as well.

Any ideas?

Respectfully,

Gary Oxner / Pinellas Park, FL

 

[Silvertip]

Re: Charging Problem

Swap positions of the two batteries. If the problem moves to the other position, have the battery load tested. Even a new battery can fail in a short time so a 1-1/2 year old battery certainly can. If the good battery shows shows not being fully charged, then I'd suspect the charger.

 

[cjames]

Re: Charging Problem

clean all the connectors, like take them apart and clean them with a wire brush or the special tool they sell for cleaning posts and terminals. You still may have a bad battery, or a bad cable, or a bad/dirty/loose connector. In the 24V bank, if one of the batterys is bad, it will do its best to bring the good one down with it, and it will be sucessfull. I'd also investigate the wiring from the charger, it sounds like you are using a 3 bank 12V charger, with indicators for the 3 different batterys. Try swapping the charge lead from the suspect battery to another battery, and see if the problem follows the battery, or the charge circuit. Ive never tried charging a 24V bank with 2, 12V charge circuits either. The circuitry in the charger may not know what to think because its essetially seeing one 24V battery, not two seperate 12V batterys. Let us know what you find!

 

[wire2]

Re: Charging Problem

>>Ive never tried charging a 24V bank with 2, 12V charge circuits either. The circuitry in the charger may not know what to think because its essentially seeing one 24V battery, not two separate 12V batteries.<<

No, it would be 2-12v chargers on 2- 12v batteries. Each charger/battery is one closed circuit.
The fact that the + of one is wired to the - of the other to sum up to 24v has no affect on either circuit.

I agree, swap charge leads and/or batteries to find the weak link.