Trolling motor battery charging question...

[RandyJ]

I'm sure this can be done but never tried it and don't know what to order or ask for. Surely it is common or someone has done it. I want to wire my trolling motor battery to my start battery so that it will charge from my outboard motor but won't draw off of the starting battery. Seems that it should be easy to do with a diode in the circuit. Can anyone clue me in on what to do or how to do it so I can skip all the experiementing???? Both are common, simple 12 volt batteries/circuits.

 

[Silvertip]

Re: Trolling motor battery charging question...

Yes this is possible but a diode is not the answer. First -- what is the alternator output current of your engine. Unless you have an engine with at least a 20 amp alternator (and even at that) you would only extend run time and not come close to fully charging the troller battery. The average troller (say 45 - 55#) draws well over 40 amps at maximum draw. Therefore, even if your engine (assuming its an outboard) had a 20 amp alternator, you would need to run wide open for nearly two hours to replace the current the motor takes in one hour. If you have an I/O with a 60 - 100 amp alternator that's a totally different scenario. Back to an outboard. The best way to do this is to install a dual battery swtich or an ACR (automatic charge relay). Both of these have been discussed to death on this fourm so use the SEARCH feature to find the posts.

 

[RandyJ]

Re: Trolling motor battery charging question...

Thanks... that gives me enough to go on. I just knew what it does but didn't know what it is called so I could do a search. I do appreciate the information very very very much!