Charging trolling motor batteries

phx5kegsman

Petty Officer 3rd Class
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Apr 10, 2021
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Hello. I usually hang out in the Johnson/Evinrude section, but I have some questions about batteries. I am currently running a 12V Minn Kota Edge powered by two 12V flooded lead acid batteries, wired in parallel, for longer run time. To charge them, I have been using a basic, but newer digital charger. I connect one lead to the positive of one battery and the other lead to the negative of the second batteries. Both batteries were purchased at the same time, and are identical. They are a few years old so I may have to replace them soon. Also, my boat was previously set up (before I bought it) for a 24V. The person I bought it from had the current 12V minn Kota wired up to just one, of the two circuit breakers. When I added the second battery, I removed both of the old breakers and wired a new 50A breaker between the battery switch and both trolling motor hot leads going to the motor at the bow. I've been running this setup for almost three years with no issues, other than lack of power, as the Minn Kota is only 45lbs of thrust. That's the backstory. Sorry if it was a bit lengthy, lol!
I was recently given a used Motor Guide Tour 24V 82lbs of thrust. It's an older model, but is in good condition and runs great. I have some wiring questions about going back to a 24V setup. Do I need two breakers, or will one 50A be enough? If so, will the configuration that I have now work? Can I just wire the batteries up in series and call it good? The battery switch is for dual batteries. Is there any benefit to isolating each battery?
My next question has to do with charging. I want to buy an onboard charger, but don't want to break the bank, lol. Does each of the two batteries need to be charged by itself, requiring two charging banks? I already need a two bank charger for my trolling and start batteries. Would I now need a three bank charger? I hope not because the price seems to jump up a lot between two and three bank chargers. Any help or advice would be much appreciated. Thanks!
 

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alldodge

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Don't need to change anything other then how the Bats are wired. Breaker measures (so to speak) current and doesn't matter if it's 12, 24 36 etc. It will trip if current exceeds 50 amps which will disconnect all power
 

phx5kegsman

Petty Officer 3rd Class
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Apr 10, 2021
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Thank You! Any advice on charging? Can I charge both batteries at the same time or do I have to charge each one separately?
 

alldodge

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Either need a 2 bank 12V charger or single bank 24V charger
If you got a 3 bank you could do all Bats at same time
 

phx5kegsman

Petty Officer 3rd Class
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Apr 10, 2021
Messages
83
I have a two bank charger. Would that only take care of the two trolling motor batteries , then? When I had the batteries wired in parallel, I would hook the pos. charger lead to one of the batterie's pos. post. I hooked the neg. charger lead to the neg. post on the second battery, thus, charging both batteries with one charger (bank). Would that still work with the two batteries wired in series?
 

alldodge

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No it won't work in series. Your charger was 2-12V outputs it can do only one Bat on each bank
 
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