Deep Cell or Dual Purpose for back-up battery?

[Doonbuggy]

I have one deep cell for my trolling motor and a starter battery for my gas motor.

When out for longer periods of time I don't want to worry about my trolling motor dying on me so I want to have another battery on hand as a back-up if needed.

For the back-up should I get just a deep cell or should I look at getting a dual purpose?

The two batteries I have now are only two years old so this back-up battery most likely would only be used for the trolling motor. Thanks.

DB

[PierBridge]

Deep cell would be my choice in this apllication.

[Ralph Wiggum]

I'd stick with a deep cycle, as well. It won't have any problems starting your outboard if need be.

[Shack]

I will thrid the deep cell. I not only indorse my statment, I own a third battery that is a deep cell . It has saved the tail end of a trip many times. Just remember to check charge rate of battery once and awhile. Good luck!

[Cabela10]

Deep Cycle.

[RedDB76]

Ditto with everyone else. A few years back, I thought it would be a good idea to get a dual-purpose to run all the time and have a backup deep cycle for those days where I'm using the trolling motor all day.

I should have just gotten another deep cycle. The dual purpose doesn't last anywhere near as long as the deep cycle, and, if you do run it down, it will take forever to charge back up from your gas motor (if it still has enough juice to start your main motor).

So now I run a starting battery and a deep cycle, and bring along the dual-purpose if I think I'll run the deep cycle down during the day.