Trolling Motor Battery Isolator

I have a 12v. trolling motor battery. Am considering installing a battery isolator between starting battery and trolling motor battery to allow alternator to charge trolling motor battery when running engine, but not allow trolling motor battery to draw from starting motor battery. My kicker motor is elec. start with alternator which I hook up to trolling motor battery to get some re-charge of trolling motor battery. Want this primarily for Canadian fishing trip where we don’t have electricity. Anybody use one. What type? Any problems/suggestions?

Thanks

A good friend of mine uses one of these Solar Battery Chargers when camping or in Canada. (15 watt model) I was sceptical at first, but these thing really work well. And after 4 years of use, it is still working like new. See Link to Cableas:

http://www.cabelas.com/cabelas/en/templates/product/standard-item.jhtml?id=0000901013860a&navAction=push&navCount=0&indexId=&podId=0000901&catalogCode=IC&parentId=&parentType=

Another thing to consider. Your kicker may have an charging output of 6 amps. That output is rated at wide open throttle, not trolling speed. At low speed, that output is 1-3 watts max, not a whole lot of power.

J.