Trolling Motor Batteries

I need to confirm the correct way to hook up two 12 volt batteries so that they act as one.
Looking to maintain a 12 volt system, not a 24 volt one.
If I remember correctly, I need to connect the positive to positive and the negative to negative.
Any one care to confirm this?
JWB

Yes, pos to pos, neg to neg. Make sure to run your t-motor cables off the same battery. Don’t cross over. Same when charging.

Thanks Jon,
I have a Dual Pro SE 2-bank on board battery charger.
I would assume that the connections to the batteries remain the same. One bank to each battery?
JWB

Pretty sure you want to use a single bank for both batteries.

-J.

Jon’s correct..unless you disconnect the two.

Think I’m going to try and contact Dual Pro and ask them that question.
Let ya know what I find out.

Hey Brian,
Didn’t see your post yet when I put in my last reply.
I did fire off that question to Dual Pro anyway just to be sure.
Thanks for the help guys!
JWB

Here is an excellent thread on wiring. After looking at it, I see I screwed up my wiring. 12 v parallel is as Jon described it. Running 24v system requires xing from + to –

http://www.walleyecentral.com/dc/dcboard.php?az=show_topic&forum=6&topic_id=139456&mesg_id=139456&listing_type=search

Just received a return call from a representative of Dual Pro.
According to him, each battery should be hooked up to a seperate bank from the charger.
He mentioned that even though there is a jumper going between the two batteries, they should still be hooked up to there own seperate bank of charging wires.
I guess I’ll know tonight when I finish wiring it!
JWB

Sounds right to me, otherwise you’re charging two batteries with one bank, instead of two batteries with 2 different amp banks. If that makes any sense. Two batteries on one amp bank would take twice as long as each on their own bank. IIRC…

Sorry, doesn’t make any sense at all to me…

Once you connect the 2 batteries in parallel, you basically have one battery with twice as many cells. It would seem to me that if you hooked up two 12 volt power leads, you would be charging at 24 volts to a 12 volt system.

So, the only explanation I can think of is that particular charger has a switcher built in that alternates the power on and off to each bank of the charger. Therefore, the charger is still charging 2 batteries with one bank of the charger at any given time.

If you hooked up 2 separate 12 volt chargers to those batteries while they are connected in series, you would either fry your charger immediately or blow the battery when the charger is plugged in. I know this from experience.

Jon i think Dual pro is saying that there system reads the state of charge and if you hook the two banks up to two batteries hooked together that they will work by reading charge volumn and will only charge what they need. Not all chargers will do that and could harm the batteries.

Jon maybe you said it wrong. You can take two seperate ac chargers and hook each one to a different battery even if they are in series and they will charge fine. Remember two seperate chargers never cross each other because do not use the same ground. If you hook up the chargers in series then you will cause a problem.

I finished hooking my batteries up the other night.
(+ to + and – to -)
I then plugged in the Dual Pro 2-bank on board charger and it appears to be working just fine. Each battery is connected to its own bank of charging wires.
According to their manual, if anything is hooked up wrong, you will get red blinking LED’s. I have already seen these because when I bought this rig and plugged it in, thats what I saw. Thats what started me on this quest to get it all straightend out as soon as possible.
I’ve cetainly learned a few things about batteries, chargers and the like this week.

Quote:

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You can take two seperate ac chargers and hook each one to a different battery even if they are in series and they will charge fine.

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When I tried that, both chargers toasted and nearly started a fire.

-Jon J.

Yes you can. That is how the ac chargers work. They are two or three seperate chargers and they do not use a common ground. These things are hard to explain with no diagram to show. If you hook up pos and neg of ac charger to batt one and pos and neg of second ac charger to batt two there is no common wire. If you have a phone number i would be happy to call you and exsplain it better.

Being a somewhat normal human, means that from time to time, we will make some pretty goofy mistakes.
Being a fisherman, means that we will get a few extra chances to proove that first theory correct.
Which is exactly what I did last night when a friend, who also happens to work as a service techinician for a local lund dealership, helped me out with a few rigging problems.
Well one thing led to another, and he was going over my boat from one end to the other, giving me lots of good information on my boat.
He took a good look at my trolling motor batteries and confirmed that I did indeed have them hooked up correctly for a 12volt in line connection and the on-board charger was also hooked up correctly.
Why then, did the LED’s on my trolling motor not indicate the level of charge for the batteries?
Ahh maybe, its because its a 24volt trolling motor???
Dang, I hate when that happens!
Well he took pity on me and straightend things out.
Maybe now I can spend more time fishing this weekend and less time trying to figure out how everything on this rig works.

Live and Learn…happens to us all!

good job,,,, the important thing is, you will be trolling better and more with less worries. congradulations.