Dual Battery setup for 12volt trolling motor??

[outdoorsup]

Ok, I'm not an electrician by trade, so here is the question. I want to run two deep cycle batteries together on either the trolling motor or as a starting battery for the motor, both of which are 12volt. What are the pros and cons and the the correct pattern to hook it up. I believe Pos. to Pos and Neg. to Neg. and I should have a 2 battery, 12 volt battery bank. I should never have to worry about the engine not having enough juice to start. Ideas.

[Barnacle Bill]

We have been using this set up on my buddies boat for years with no problem. He has a Merc 25 on it so it doesn't take much current to start it. It is best tho if the batteries are the same type and age.

[bassadict69]

I run my batteries for the trolling motor on my bass boat in parallel. Run a cable from pos to pos & one from neg to neg just like you said. I hook the pos lead from the TM to one battery & the neg lead to the other although I don't think it matters much.

I don't see how doing this could help any as a cranking system for the motor. Running them in parallel, you still only end up with 12v just as if you only had one battery. The BIG difference is that with a trolling motor, it is pulling a little off each of the parallel batteries giving you a longer run time. With one battery, I can bass fish for about 8 hours, with the parallel set-up, I can run it for 2 + days before draing them.

[bowdenja]

Just a suggestion............. hook up one battery for trolling and the other hook up for both cranking and trolling. You can put a switch in-line to change over when you troller battery get low and you always have a pretty hot battery for cranking.

At least this way you know when the cranking battery has been used.

john

[tcounty]

I run 2 deepcell batteries for the trolling motor and a lawn mower battery for the big motor. I've been using the same lawn battery for 2 years. Saves alot of weight in the boat and I can run my deepcell bateries as low as I want with no worries.

[kscrappiehunter]

I have one huge deep cycle going to my trolling motor right now. It's just not cutting it for a full day of fishing. So you guys are saying that I can take another battery, run wires positive to positive and negative to negative and attach them to the existing trolling motor battery and it should work. I have a one bank on board charger. Will it charge both batteries as long as I have wires connecting the first battery to the second?

[crappie cowboy]

Hey, I run a series 29 deep cycle battery and it will last a lot longer than the
smaller series battery's. You will have to change the smaller battery tray to
the 29.
I had the same problem that you had with it lasting all day on windy days, not
any trouble going all day now.

spider rig man

[bassadict69]

I have one huge deep cycle going to my trolling motor right now. It's just not cutting it for a full day of fishing. So you guys are saying that I can take another battery, run wires positive to positive and negative to negative and attach them to the existing trolling motor battery and it should work. I have a one bank on board charger. Will it charge both batteries as long as I have wires connecting the first battery to the second?

Yes, it will charge both batteries. You may want to considering buying 2 new batteries to do this with. If you put two different batteries or one old & one new, it will pull off one faster than the other.

[Ranger R61]

I have 2 12 volt batteries hooked up in parrallel (pos to pos and neg to neg). You should use fairly heavy cables to connect the batteries together, maybe 10 guage. If you use lighter guage cable its resistance can keep the battery your charger is not connected directly to from charging as fast as the battery it is connected directly to. I used to have trouble charging the second battery until I used heavier guage cable to connect the batteries.

Hope this helps.
Ranger R61

[trypman1]

I needed this info, thanks.