# Charging 24v Trolling Motor Battery Setup?



## acolic

Hi

I'm confused with how to charge a 24 volt battery system consisting of two 12V marine batteries.

I found this on the net:

"Connecting Your Battery ChargerOnboard chargers are equipped with positive and negative leads for each battery. Simply wire each bank of the charger to each battery accordingly. "

Does that mean I need to get a trickle charger with two positive and two negative leads and wire one positive and one negative to each battery?

Appreciate the help. 





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## tomme boy

Depends on if you have your batteries run with 2 wires or 4. If you have 4 wires running up to the motor, run one charger on one battery and run one on the other. Just make sure to unplug the motor from the battery connection before charging.

If you have two wires running up to the motor then you need to unhook all wires and run a separate jumper wire from one + of one battery to the + of the other battery. Then do the same with the - side of the batteries and then hook up the charger as normal. + to + - to -


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## acolic

I wired it with two wires going to the motor. 

Positive from Battery A to the trolling motor.
Negative from Battery A to positive of Battery B. 
Negative of Battery B to the trolling motor. 


Are you saying I have to unhook all the connections to both batteries prior to charging now?


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## gnappi

acolic said:


> I wired it with two wires going to the motor.
> 
> Positive from Battery A to the trolling motor.
> Negative from Battery A to positive of Battery B.
> Negative of Battery B to the trolling motor.
> 
> 
> Are you saying I have to unhook all the connections to both batteries prior to charging now?
> 
> 
> Sent from my iPhone using Tapatalk



Are you using one of the TM quick disconnects that Minn Kota sells? Is your charger 12 or 24 volt?

If you're using a 24 volt TM *and* 24 volt charger, just connect it to where the trolling motor connects. If you have a MK QD connector use that couping it makes it easy.

If you have a 12 volt charger, then *WITH THE TM and any other 24 volt device disconnected* you can charge the batteries individually just like your car... charger + to battery + charger - to battery - without disconnecting the wire between the batteries.

The down side is you have to charge (and trickle charge) the batteries individually.


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## acolic

Hi,

I don't have Minkota quick disconnects but I believe I'm using something similar. 
I also do not have a charger yet so I can pickup up a 12V or a 24V whatever is easier.

I have attached two pictures to show my current setup.

The first shows the bulkhead at the bow which has a socket to plug the trolling motor into. From the socket I ran a red and black 8 gauge wire back to the battery compartment.

The second picture show the battery setup.
The red wire from the bow socket went into a 60 Amp fuse and then to the positive of one of the batteries.

I then bridged the negative of battery A to the positive of battery B. 

I then connected the negative from the bow socket to the negative of battery B.

Hopefully this makes more sense.

If so what's the easiest way to charge the two batteries preferably simultaneously?

Thanks


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## LarryMc

The simplest way to do it is to buy a 12V two bank onboard charger, then connect one bank to one of your batteries and the other bank to the other battery. Then all you have to do to charge your batteries is plug the charger in, you don't have to disconnect anything.


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## gnappi

If you want a separate charger NOT on board, clearly the easiest path is a 24 volt external charger connected to the TM connector. 

But... a split charger as Larry suggests may maintain the "float" charge better, I don't know, I don't know if there's much practical research and or development on this subject / application.

I use a standalone charger / float charger and one of my two 12v batteries (different groups and AH ratings) I keep disconnected from the charger and only connect once in a while to keep it "topped off"


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## johnbt

I use two Schumacher SSC-1000A lightweight smart chargers and don't even disconnect my Maxxum 70 or any of the wiring. I do turn it off though. It's been 3 years and no problems so far. 

My buddy (I've posted his 10.5# largemouth pic in another thread) has an early Maxxum 70 on his boat and has been using two of the old style heavy chargers he found at yard sales and he never disconnects anything either. A guy that taught him a lot about bass fishing 30 years ago charges his the same way and he's a high-dollar electrician, so I just blindly follow along. Fwiw, the electrician has a garage I want - it's a double-doored drive through and big enough that he can park the truck and boat without unhooking it.

We pretty much stick to 2 amp charges if time allows.

John


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## tomme boy

You only need one 12V charger. 

1) unhook the + wire going to the t-motor
2) unhook one end of your jumper wire.
3) Take the end of the jumper wire and hook it up to the same polarity that the other end is hooked up to. 
4) You will need another jumper wire to hook up both of the other terminals not hooked up. I do +,+ for this one. Just make sure the other two are -,-
5) hook up your 12V charger. + on one battery and - on the other battery. 

It took longer to type this that to actually do it. 

I swap the charger clamps to different post each time I charge the batteries.


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## acolic

Hi,

I bought a NOCO GENM2 Mini 8-Amp 2-Bank Waterproof charger and hooked one set of leads to one battery and the second set of leads to the second battery and after 15 hours the charge lights for both bank are still red.

I double checked the polarity of both leads / banks and they are correct.

I am going to remove the jumper between the two batteries and see if that starts the charge process.

If anyone has a suggestion it would be appreciated.


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## johnbt

Before I hazard a guess, what kind of batteries are you charging - brand and size - and how run down were they when you started?

Meanwhile, I googled your charger and ended up at the Crutchfield site fwiw. The specs say two 4 amp banks and "charges batteries up to 100Ah" https://www.crutchfield.com/p_598GENM2/NOCO-GENM2.html?tp=6726&awcp=1t2&awcr=194294770016&awdv=c&awkw=genm2&awmt=p&awnw=g&awug=9008454

I doubt it would take 25 hours, but 4 amps into 100 Ah = 25.

I've been charging my 3 large Wal-Mart deep cycle batteries since sometime last night - at 2 amps. The lightly used one in the back of the boat was at 100% this morning and the two for the trolling motor were 96% and 97% and still on the desulfation mode at 15+ volts. I need to go out to the garage and check, but I'm sitting in air conditioned comfort right now.

Your charger manual is on the Crutchfield site. The chart on page 10 says a 120 Ah battery will take approximately 15 hours to charge. I think I'd give it a few more hours. Is it charged yet?


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## acolic

I can't believe it but it took over 15 hours to charge the batteries.

Thanks for all the help.


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## gnappi

acolic said:


> I can't believe it but it took over 15 hours to charge the batteries.
> 
> Thanks for all the help.



Questions? When you ran them, what did you discharge them to, and did you remove the jumper?


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## RiverBottomOutdoors

Charging the batteries individually like Larry suggests is best practice.


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## acolic

gnappi said:


> acolic said:
> 
> 
> 
> I can't believe it but it took over 15 hours to charge the batteries.
> 
> Thanks for all the help.
> 
> 
> 
> 
> Questions? When you ran them, what did you discharge them to, and did you remove the jumper?
Click to expand...


I just picked them up at bass pro I don't know how much they were discharged.



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## acolic

RiverBottomOutdoors said:


> Charging the batteries individually like Larry suggests is best practice.



It is going to be a pain to take off that jumper. 

I'm going to try to find out if there some quick release I can use. 


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## johnbt

You don't have to remove the jumper to charge them individually. Just use one charger/bank on each battery.

I didn't believe my buddies when they told me many years ago how they charged their 24v systems, so I researched it. They were right.

They make 24v chargers, but they will only charge up to the weakest battery's maximum potential. That's why you put a charger on each battery.


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## RiverBottomOutdoors

johnbt said:


> You don't have to remove the jumper to charge them individually. Just use one charger/bank on each battery.
> 
> I didn't believe my buddies when they told me many years ago how they charged their 24v systems, so I researched it. They were right.
> 
> They make 24v chargers, but they will only charge up to the weakest battery's maximum potential. That's why you put a charger on each battery.




This is all correct.


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