boat onboard charger...Help!

[TENRMORE]

OK, I bought a boat and the batteries were dead...Its a 36 volt trolling motor. There are three batteries under the center console and one cranking battery. I bought three new batteries, two of the batteries are charging fine I have killed two interstate batteries on the other one.

I have a two bank charger for two of the trolling motor batteries that is charging fine.

I have a two bank charger for the other trolling motor battery and then the cranking battery. This is the one that is killing the trolling motor battery. When I took it back the guy said it looks like it was hooked up backwards. The second battery seems to have done the same thing.

I have the three batteries wire in series, do you think it could be back feeding or something. I took the two bank charger out of the boat and tested it and it seems to be fine.

Any suggestions, I'm not sure if they will take another battery back..

[Quackerbox]

So you have two 2 bank chargers. One is doing two troll motor batts and one is doing one troll motor batt and the cranking battery?

Im not an expert but Im thinking the charger thats doing both the cranking battery and one trolling motor battery cant be the exact same charger as the other. Juice needs to go into those batteries differently. IE..trickle and maintain on the troll batts.

FTR: I have a 24V trolling motor and Im on my second set of batteries which are 4 years old. I bought a new cranking battery last year to replace the one that came new with the boat. My boat is an 06' and I have NEVER put a charger on my cranking battery. However the other thing that runs on that battery is the motor and tilt/trim

[TheGeneral]

I have a two bank minkota charger. One set of leads on cranking batt and one on trolling batt. Keeps em both maintained just fine. As far as I know it's okay to charge two diff batts off of one two bank charger.


I think you may be better off with a single 4 bank charger. The charger isolates each battery and charges them each independently, but they are still wired in series for the 36v and single 12v setup.

[Javelin]

I have terrible luck with onboard chargers, I went back old school

[rtp]

Yeah I have an 05 boat and just put a new trolling motor battery in for the second time. I have never had to replace my cranking battery. Probably just jinx myself. Anyway maybe don't worry about trying to keep the cranking battery on the charger.

[TENRMORE]

So you have two 2 bank chargers. One is doing two troll motor batts and one is doing one troll motor batt and the cranking battery?

Im not an expert but Im thinking the charger thats doing both the cranking battery and one trolling motor battery cant be the exact same charger as the other. Juice needs to go into those batteries differently. IE..trickle and maintain on the troll batts.

FTR: I have a 24V trolling motor and Im on my second set of batteries which are 4 years old. I bought a new cranking battery last year to replace the one that came new with the boat. My boat is an 06' and I have NEVER put a charger on my cranking battery. However the other thing that runs on that battery is the motor and tilt/trim

Your first statement is correct...the cranking battery is fine, its the other trolling motor battery that I'm having trouble with. I'm not sure what I'm going to do, I agree you don't need one on the motor but it was already hooked up like that.

[W-L-F]

what votage charger do you have ????

[Quackerbox]

My manual has a way to check each legs voltage.

[TENRMORE]

batteries

Here is apicture on how I have them wired...

[Stolle]

We have a 4 bank battery charger and it charges 2 auxilary batteries and 2 cranking batteries. It works fine. Each bank(If workng correctly) should charge each battery independently no matter what it is used for.

[hawgman_1]

I also have a four bank charger on mine and it is like your set up, 36V TM and 1 cranking battery. My charger also works with no problems. The one thing you can try is pulling one of the battery cables off battery three when you charge it and see what happens.

[Capt.Bryan]

Maybe the bank going to # 3 battery is bad. I have had the same problem happen in the past and it was one bad bank on the charger burning up the battery. Petty nerve racking when it ruins a new battery and or fishing trip.

[expressfish]

agree w/ capt brian, charger must have a bad bank