Thread: Is my Dual bank charger killing my TM batteries?????

On board chargers will "eat" a battery if left unpluged for a period of time and yes they will not charge a dead battery. I would try hooking an amp meter in line on the positive wire to see how much of a draw there is, may be that your charger is bad, but I have seen different brands do the same thing, an old style charger that has switches to go from 10 then 50 amp may bring your battery back, or hook up a small 12 volt light then your charger to get voltage flowing through the battery and see if it will take a charge then. My opnion, I don't and won't own an on-board charger.

Are you saying a charger will draw a bat. down when not plugged to 120v ?

Originally Posted by Archerguy1

On board chargers will "eat" a battery if left unpluged for a period of time and yes they will not charge a dead battery. I would try hooking an amp meter in line on the positive wire to see how much of a draw there is, may be that your charger is bad, but I have seen different brands do the same thing, an old style charger that has switches to go from 10 then 50 amp may bring your battery back, or hook up a small 12 volt light then your charger to get voltage flowing through the battery and see if it will take a charge then. My opnion, I don't and won't own an on-board charger.

Thank you for the reply

I went with the Minn Kota because I had thought they were supposed to be pretty good ones. I also thought the digital circuits prevented this....did not know that could happen.

Originally Posted by wilbur

Are you saying a charger will draw a bat. down when not plugged to 120v ?

I have seen many a battery come in the shop dead and the only thing hooked to it is an on board charger, so yes I have seen them draw a battery down and worst of all they will not charge a dead battery, I have people come in and say the charger shows green but no power and I load test the battery and it has no volts, old style charger usualy brings it back enough for the on board to start charging.

You are the first person I've heard of that dont like...no, LOVE...the onboard chargers. Hmmm....

Been using them for years and Minn Kota is one of the best. You are only supposed to have them unplugged when you go fishing....the rest of the time they are supposed to be plugged up. Mine stays plugged up except when I hook the boat to my truck. Have not had any problems and get long life out of my batteries.

I've been using them ever since they came out with them. The only way they can draw a battery down is something be defective with the unit. It would be simple to check with an amp meter.

The reason an Onboard won't charge a dead battery is safety. A dead battery is indistinguishable from a wiring short to the charger. Anything built into a boat needs to be safe.