My on-board 2-bank chger won't go to green on the cranking battery (maint free) even tho the other bank chgs tm batt fine.  Switched em over and did the same way.  Dealer where I bought batt tested it thouroughly with no probs showing up. I can upplug onboard chger then hook up portable 10 amp chgr for 10 mins to C batt and the light for C batt WILL go to green THEN. Its like it can't shut off charging  batt without zapping it with portable charger.  Dual Pro has tried to help but prob persists. Any ideas?  Papadew.

how many amps is your on-board? It sounds like you may have something on the boat that is drawing current out of your cranking battery. Try to unhook everything from the cranking battery and see if it goes green then. Sometimes a small on board charger cant put out enough to fully charge a battery as long as there is something constantly draining the battery, make sure your fishfinders are off, I've made that mistake more than once while fishing night tourneys,bring it home and plug it in only to find 2 days later I have left my finders on

I agree with Gambler to charge the cranking battery I always disconnect the battery from the boat if something is left on then there's a constant drain on the battery also with the battery hooked up your sending the charge through the entire boats electrical system there by reducing the amount of charge to battery, resistance and current draw are created by all the wires on the boat. I also do the same, when needed  on my suv as well when charging a dead battery.

Hope this helps.

Chow

The Pa Angler

I took off my onboard charger because of a similar problem and went back to portables. A little more hassle but I know my batteries are full every morning.

Actually did have a drain on C batt at first, front livewell switch was on but problem didn't go away after I turned it off.

I'll disconnect everything but the o/bd chgr and see if it goes to green.  I'll turn on the running lights to get the C batt to drain enough to go back to red, and then reconnect o/bd chger and see if it goes to green.  If it does, I'll just have to look until I find the drain I suppose!  BTW...this is the most useful and fastest website for help that I've ever hooked up with...Thanks,  Papadew

Your welcome and your moving into the right direction to finding and correcting the problem.

Chow

The Pa Angler

I am not sure but it might be because the battery is maintance free. I think they need a different type of charger. I would check with the people that made the charger & the battery company.

My portable charger has three settings one for maintenance free, one for low maintenance and one for a full maintenance battery. If your battery has caps that you can remove it's not maintenance free the maintenance free batteries today are sealed that's what what I was told by the boat dealer. Also my portable charger has two amp settings 2amps and 10amps I always use the 10amp setting.

To get more info on batteries go to Interstate batteries website there's info there that explains the different types of batteries.

www.interstatebatteries.com

Chow

The Pa Angler