Dual battery system Grady Tournament 190

[Wrestling Coach]

I recently purchased an '83 Tournament 190 that the previous owner has installed dual batteries that work off a switch so that one is in use and charging while the other is not. Flip the switch and it goes the other way. Both batteries are marine batteries. One is a cranking battery but the other is a deep cycle. Any reason the other battery should be a deep cycle? Boat has electric downriggers, two fish finder/depth sounders, VHF radio, bilge and lights. Nothing out of the ordinary.

 

[Curmudgeon]

Depends on your usage. Doesn't really matter what batteries you have if you always run your engine and never deplete either battery to any extent. If your electrics and usage pattern place a load on the deep cycle and it requires any significant recharge time, don't replace with a starter. A deep cycle will function OK as a starter, but a starter will have a significantly shorter life if deep cycled. Depending on the engine, the ability of a two-stroke to recharge a battery is greatly exaggerated.

I have a T-22 with dual batts and a switch, both are deep cycles. I have all electrics run off the 'common' terminal, which means using the battery selected by the switch. I alternate batteries by the trip, which means I have a battery in use for the day and a fully charged one in reserve. I consider the 'both' position of the switch to be an emergency position, and the trip is over if I have to move the switch there ... :wink:

 

[seasick]

All good advice and info. I also alternate which battery I use but if I am going where the return trip is 20 minutes or more, I use one battery to get there and switch to BOTH for the trip back. That helps top off both batteries.