# two new 12 volt batteries wired in series for trolling motor



## Gotem (Oct 19, 2014)

The deep cycle battery is getting old. Since I tend to use my 12 volt trolling motor a lot, is it wise to get 2 New deep cycle batteries and wire them in parallel. According to an article in Great Lakes Angler this would keep the voltage the same at 12 volts, but it would double the amp capacity. I would imagine that I would get a 2 bank battery charger. The main advantage I figure is a longer run time without upgrading to a more powerful trolling motor and a 24 volt system. Has anyone actually done this? Is it wise? Are there any unforseen problems or issues with this setup? Any input would be appreciated.


----------



## gillhunter (Oct 19, 2014)

I run 2 12 volt deep cycle batteries to power my 12 volt trolling motor (plus a 12 voltj starter battery), with a 3 bank charger. I installed them with a switch and run them one at a time. I usually only run one one an outing, but it's nice to know you have a backup. My setup is on the first couple of pages in my built tread in case your interested.


----------



## Zum (Oct 19, 2014)

Other than taking up more space, you'll be fine.
If the batteries are the same,close to twice the run time...
Keeping them wired in parallel, you can get away with a single charger...its just one big battery.


----------



## New River Rat (Oct 19, 2014)

Your title says series, but the post says parallel. In series is 24v, parallel is 12v.


----------



## fish devil (Oct 20, 2014)

:twisted: I run two (31 series) batteries in parallel for my 54lb bow mount trolling motor. Been doing this for about 14 years with no problems at all. My third battery runs my 54lb transom motor. I only use a two bank charger for the three batteries.


----------



## typed by ben (Oct 22, 2014)

i'm trolling with 2 31 series AGMS wired in parallel and a 4 bank charger. just doubled up the leads and she works like a charm.


----------



## kissfan4 (Oct 31, 2014)

Series = Voltage is additive, Current stays the same.
Parallel = Voltage stays the same, Current is additive.


----------



## Moedaddy (Nov 9, 2014)

Zum said:


> Other than taking up more space, you'll be fine.
> If the batteries are the same,close to twice the run time...
> Keeping them wired in parallel, you can get away with a single charger...its just one big battery.



What he said.


----------



## TexasLoneStar56 (Nov 9, 2014)

New River Rat said:


> Your title says series, but the post says parallel. In series is 24v, parallel is 12v.



hhmm....I was just thinking the same thing. #-o 
(Glad I'm not the only one that saw that. Series can burn up stuff, and we sure don't want him to burn up anything.)

Glad he's getting some good advice from others, as well.


----------



## Y_J (Nov 10, 2014)

OK Somehow ya'll got me a bit confused here. To run dual batteries but keep it a 12v system how do I connect the two?


----------



## New River Rat (Nov 10, 2014)

12 volt= parallel






24 volt= in series


----------



## Y_J (Nov 11, 2014)

Thanks, Rat. That cleared it right up for me. Appreciated.


----------



## TexasLoneStar56 (Nov 12, 2014)

Awesome graphics Rat. =D> 

Keith
Tyler, Texas


----------



## Planepilot (Dec 23, 2014)

As a follow on to the OP, do my batteries need to be next to each other? I want to upgrade to a 24 volt TM. Since the batteries are heavy, I want one in the bow, the other in the stern for better weight distribution. The batteries would be about 12 feet apart. thx


----------



## New River Rat (Dec 23, 2014)

I've done it, absolutely no adverse occurrences. I basically have a large 12 volt battery (in theory) so a single bank maintenance charger is all I need. Had this set up about +/- 5 years.


----------



## JMichael (Dec 23, 2014)

Planepilot said:


> As a follow on to the OP, do my batteries need to be next to each other? I want to upgrade to a 24 volt TM. Since the batteries are heavy, I want one in the bow, the other in the stern for better weight distribution. The batteries would be about 12 feet apart. thx


Just be sure you use the appropriate size cable to connect the two batteries. Being that far apart will require that you use a larger diameter cable than if they were sitting next to each other and close to the TM.


----------



## GTS225 (Dec 25, 2014)

Planepilot said:


> As a follow on to the OP, do my batteries need to be next to each other? I want to upgrade to a 24 volt TM. Since the batteries are heavy, I want one in the bow, the other in the stern for better weight distribution. The batteries would be about 12 feet apart. thx


***************************************************************

No, they don't. You can mount one fore, and one aft, and as long as you wire them in series for the 24VDC motor, you're good. You do need to be aware, though, that the longer the distance between the batteries, the higher the risk of voltage drop due to resistance in the leads. You might want to bump your cables up a size as a precautionary measure.

Roger


----------



## starzstuff (Dec 27, 2014)

Thanks for the post and answers. I had the same question. I am going to use an old pair of jumper cables from the front to the back. Just going to adapt the connectors.


----------



## GTS225 (Dec 27, 2014)

Starz; Check the size of the copper conductor through those jumper cables. I've seen low-dollar cables with nothing more than 10 gauge wire through them. 10 gauge is rated at something like 35 amps. Not gonna work very well starting a car in cold weather that is trying to draw 200 amps to get running.

Just a heads-up.

Roger


----------



## starzstuff (Jan 28, 2015)

Thanks Roger. They were actually pretty good ones. I placed both batteries in the front ran the cables to the back of the boat and created a connector board of sorts for the positive and negative in the rear section of the boat. The engine cables run off it and then a separate pair of cables to a switch and negative bus bar. I have then a smaller battery for the trolling motor as I wanted to keep that on on a different circuit at the front. Mostly about weight distribution and keeping the batteries away from the gas tank at the back.


----------

