Doubling Battery Power?

[Tadpoletodd]

I have a 12V trolling motor with a good battery but am wondering if I can wire up to an additional battery somehow. Trolling all night long in the cold this time of year is draining the single battery pretty fast. Is there any way to get more power by hooking up to an additional battery??? Any thoughts on the subject would be greatly appreciated. Thanks.

[Pat K]

You can hook the batteries up paralel. Positive to positive. Negative to negative. Still 12v but your run time should nearly double.

Pat K

[Heartman]

I like the sound of this - if I hook up my onboard charger to this parallel setup, will it affect my recharge time alot? I mean could it double? I have a Minn-Kota 15 amp charger - actually it's a 60amp charger(4X15) but I'm only using two at this time, with the other leads isolated.

[Tadpoletodd]

So, right now I have a red wire going through a fuse to the (+) terminal and black going to (-). On the 2nd battery I run a new red wire from the (+) and splice it into the 1st battery red wire just below the fuse. Or would it be better to add a 2nd fuse and splice above the other one? Am I close?

I'm bad at electrical. I can physically hook it up no problem; but need to be told the theory behind it.

Thanks!

[Pat K]

Tadpoletodd,

I would go to the auto parts store and get two 12" long jumpers and conect the automotive type posts on the two batteries. It will be heavy guage wire and have the auto type connectors on both ends. You won't have to splice into the existing wires or change the fuse location.

[Pat K]

Heartman,

You could hook one of the unused bank sets to charge the second battery and have the same charge time as now. If you use just one 15a bank it will take double the time to charge the 2 batteries.

[Tadpoletodd]

Thank you Pat K!

That's easier than I thought. I'll rig it up tonight and give it a good test tomorrow night. Thanks again.

[Ralph Wiggum]

If I'm not mistaken, it is best to do this with two identical batteries. Otherwise, I've heard that the better battery will get drained by the other one.

[Heartman]

Pat K -

If I hook seperate charger leads to each battery, which are wired in parallel, won't I be charging at 30amps? Or can the charger figure this out and compensate? A bit confused in any case///

[katoguy]

Your charger has 4 channels each at 15 amps. Hook one channel up to each battery you want charged. It doesn't matter if the batteries are hooked in series, parallel, or are independent. It doesn't matter to the charger you own.

[Heartman]

Hey Katoguy -

Thanks a ton for the info, still a bit confused. Not trying to challenge your answer or anything(I plead ignorance in this issue - BELIEVE ME!), but if I have the two batteries wired together in parallel, and put charger leads on each one, aren't I putting a 30amp charge into the two battery rig?

I just can't set it up and plug in the charger - I think I'm going to blow something up. Again, I plead ignorance in this situation. Any chance you could clarify furhter? Thanks.

[overdalimit]

These solid state chargers actually monitor the battery that they are hooked up to. (Don't know how, they just do) We have to take that at face value. So hook up the batteries in paralell and hook each battery to the charger with its own set of leads to the charger. The charger will know what to do. My batteries will recharge in about 12 hours and I have the same set up as what you are describing.

[Heartman]

Thanks, brother. I'll give 'er a go!

[delcecchi]

Quote:

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These solid state chargers actually monitor the battery that they are hooked up to. (Don't know how, they just do) We have to take that at face value.

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That is true for 24 volt setups with the batteries in series. But if the batteries are in parallel like in a 12 volt setup they just look like one big battery. Running the banks from the charger in parallel just does double the charging current, if your charger allows that.

[Lund4Fish]

I did the exact thing with my last boat I had as discussed above with running 2 batteries for my 12 volt trolling motor and hooking them up individually to the on board charger and it worked great. No problems, you'll just get lots more running time.