batteries in parallel?

mfkirkland

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Jun 8, 2011
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Boat has 3 batteries, 1 for starting and acting as house. 2 for trolling motor.
I had to replace the plug and receptacle to the TM. The plug and receptacle are jumping the 2 batteries for 24 volt to the TM.
My question, is there any reason for also wiring the 2 batteries parallel?
 

KD4UPL

Senior Chief Petty Officer
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Feb 13, 2010
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I'm not sure I understand the question. If the 2 batteries are wired in series for 24 volts then you can't also wire them in parallel.That would create a dead short.
You can't wire a 12v battery in parallel with a 24v battery set. The 24v set would try to dump power into the 12v battery to bring it up to it's voltage level which would overcharge it for sure.
 

mfkirkland

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Jun 8, 2011
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I think you answered my question. I got you on the 12 v and 24v in parallel. You cant do that, but I'm not clear on "dead short".

Leaving the start / house battery out of the question.

Someone prior to me had jumpers on the 2 batteries for the TM. I didn't look before I took em apart.
There were 2 jumpers and I cant figure out why. They must have been parallel because in my mind you only need 1 for jumping to 24v (series).. Yeah?

Should I have a circuit breaker on both batteries? There was only 1.
 

alldodge

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With 2 jumpers everything could be 12V
Look at your TM an see if its a 12 or 24V model
 

mfkirkland

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Jun 8, 2011
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The are no markings/model numbers on TM. All I know is it is a Maxxum by Minn Kota. No idea how old it could be.

I used plug and receptacles by RigRite #s 420 and 425. Wired for 24v in the plug / receptacle. The RigRite connection is very tight. I did a little trimming to make it easier to insert to plug.
I put new 50a circuit breakers on both batteries.
There are now no jumpers at the batteries.

I have moved the "house: wiring to one of the TM (deep cycle) batteries.

So now I have...
1 "marine" start / run battery isolated on its own circuit.
2 identical deep cycle batteries with TM and "house" attached. The TM is wired 24v at the plug / receptacle. House is still 12v.
All 3 are also connected to Minn Kota 315 On Board battery charger.

All seems to be working fine.
 

alldodge

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Look up "minn kota maxxum models" and it will show you 3 types
55 is 12V
70 and 80 are 24V

There are also manuals easy to find
 

mfkirkland

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Jun 8, 2011
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Thanks AllDodge, Minn Kota will even show you exactly where to find the model / serial numbers. There are no markings on my motor.
It is wired 24v and nothing has burst into flames. No smoke or funny smells. Circuit breakers are not tripping. So I am assuming I have the 70 or the 80 lb thrust.
The manuals for all of the Maxuum 24v motors are the same. word for word.
 
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