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12 volt parallel

8/11/16 @ 9:04 AM
User since 6/3/16

Has anyone run 12 volt batteries in parallel for a trolling motor? If so, what were the results and were you happy with it?

8/13/16 @ 9:32 AM
Tim Zwieg
User since 1/10/12

Nice post Bfish

8/13/16 @ 6:57 AM
User since 6/25/02

If you go with a 24 volt system with your batteries in series then make sure your trolling motor will accept a 24 volt system.  My powerdrive 55 is a 12 volt system and the motor would burn up with a 24 volt system.  Most of the higher pound trolling motors are 24 volt now.

8/13/16 @ 6:51 AM
B Fish
User since 6/26/10

Yes you can do it and it will work but when ever you hook 2 batteries together either in Parallel for 12 volts or in Series for 24 volts for trolling motors you need to take a few precations.

No 2 batteries are exactly the same, (even a small amount) one is always stronger than the other. If you leave them connected the stronger battery will always try to charge the weaker battery and will either shorten its life or even kill itself. So when you are not using your rig either disconnect the circuit or install a shutoff switch. (They range from $10 to $30) but you get what you pay for.

It is also very important with todays trolling motors that you break the circuit to your trolling motor when you charge the batteries. Todays Trolling Motors have circuit boards in them that can get wiped out by a simple voltage spike. A voltage spike can come from a charger any time you have a reduction in line voltage and then it jumps back up. This can happen from an (Air Conditioner, Refrigerator,Well Pump, Wind, or a Storm). An in-line fuse will not prevent a spike, only an overload. It may never happen to you but when you hear about guys having there mother board wiped out on there trolling motor, this is why. Yes you can unplug your trolling motor but eventually by doing that the plug will wear out. The switch is much easier and will also prevent battery damage.

I know several guys who have gone through the above scenario and have lost batteries and/or TM and we have now installed the switches and the problems are gone.

8/12/16 @ 10:35 PM
User since 9/5/09

Not trying to change the subject but.....on my previous boat ( Crestliner 1750 Fishhawk). I had a 12v 50# thrust troller for years, also ran a group 30 battery. On light wind conditions it ruled,I could move at a half mile an hour all day...with power to spare. But on days with a little a 12" chop on the water...I had to really crank up the power to fish and hold the boat where I wanted. Then I picked up a used 24v 74# thrust troller and switched to dual batteries and 24 volt power. Now the only problem I had was the occasional calm day... dialing the power down. In a chop it ruled! I could run a chop at low power settings with the 24volter where before I had to have 12 volter cranked up. The 24volt motor did everything better (except very low speed in calm conditions) and the batteries would go further between charges. So some advise... if your going to dual batteries...get a 24 volt will not be sorry you did. The difference in power is amazing.

8/12/16 @ 9:52 AM
User since 6/25/02

I have run my 55 lb. trolling motor with 2 batteries in parallel for 13 years.  Initially did it because we would vacation for a week without access to power for charging.  I just haven't changed  since we bought a place in Vilas county but it is security in case of engine failure. (Especially true when I'm fishing in mid November for muskies.) Now with trolling legal in northern Wisconsin, I am glad I have that longer battery life in case I want to troll with the trolling motor. 

I have never had an issue with batteries that are exactly the same age. One is always older than the other but I have an on board charger that I plug in after every time I come back from fishing.  I'm on the water probably 60-70 days per year.

8/11/16 @ 8:21 PM
User since 12/10/14


I have been running 2 in parallel for the last 3 years. I started with identical new batteries, and my on board charger is connected with the + lead to one, and the - lead to the other. In essence treating it as one big battery. This set up is to power a 55lb thrust Minnkota and my Helix. I Have used this same set up when powering a square stern canoe, with the trolling motor as my means of propulsion, and have run multiple days. Now, on my 14'aluminum I only use the trolling motor occasionally. Still, it definitely increases run time, and it's nice if not around an electrical outlet, say camping/ fishing for a couple days. I have the batteries at the center of the boat to distribute the weight better, away from the outboard/ gas tank. I'm very pleased with the setup.

8/11/16 @ 2:26 PM
Tim Zwieg
User since 1/10/12

Big Musky makes a very good point. Years ago I did that, essentially gives you one big battery. However you have to have like batteries cuz one could take the other one down. On my current boat I run 5 batteries. 3 for trolling motor, and two in parallel for start. That way I can run 4 electronics, 4 pumps and everything else all day long without issue.

8/11/16 @ 11:55 AM
Ed Franko
User since 5/6/15

I would get a new 27 series deep cycle battery and go with just one. I know you could run all day on a good battery. JMO

Big Ed’s Guide Service
(573) 692-6710
8/11/16 @ 11:19 AM
User since 9/4/06

my current trolling motor runs on a 12V 2 battery parallel circuit and has for the last 7 years.  I couldn't be happier.  I've never run out of juice even on the longest days.  but, I would recommend buying two brand new identical batteries to start with.  as bigmusky said, using mis match batteries can cause the weaker battery to be charged by the stronger battery and ultimately reduce the overrall gains of the two battery system. 

8/11/16 @ 11:04 AM
User since 12/22/04

when I had a 55lb trolling motor that was underpowered for my boat, I used a switch for a backup battery.  I did this as opposed to parallel connection because I did not want to have to worry about one battery killing the other and trying to match them in age, size, make etc.   

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