Charging house battery

[TRAILN]

I want to charge my trolling motor battery (12v) when out on the water. I'm torn between getting an ACR or an on-board alternator charger. They are about the same price and (to my knowledge) do the same thing. Please help me decide which to choose and why. Thanks

 

[ondarvr]

First you need to see if it's worth doing.

You need to know the output of the charging system on the boat and then figure you're actual running time on the main motor. If you have a low output charging system it will take a very long time to do any charging at all, as in several hours of running at high speed. even with a high output system it will still take a good deal of high speed travel to actually make a difference in the amount of time you can use the trolling motor.

I'm not saying it's not worth doing, it's just the value of the system may not justify the hassle and price of installing it.

 

[TRAILN]

Good point indeed. I've got a 50A alternator on my outboard. The Minn Kota on-board charger outputs 10A max. My estimated runtime is 25-50%

 

[ondarvr]

25-50% of what? It's about the number of hours (not minutes) you run on the main motor at high speed on a typical trip.

For me I couldn't extend my run time of the trolling motor by 5 minutes on the short runs I make on the main motor. Some days the main motor isn't started until I put it back on the trailer.

Depending on the charging system you buy, it will charge the main battery up first, then switch between each battery individually to charge each one separately. So the charge time for each battery can be very short on a run and you don't gain much.