# 3 Batteries, Sharing 12 volt and 24 volt Banks



## ScarsNoTatoos (Dec 29, 2020)

Morning all, can I place all 3 negative connections on the post of battery #2 (low side), or do I need to connect them to a negative grounding bar first before connecting to battery #2? Battery number one is specifically for starting, battery #2 is for a power pole and battery #2 and #3 are for a 24 V Minn Kota. Note: I forgot to draw in the 60amp breaker. Thanks in advance.


----------



## DjPic (Feb 24, 2020)

ScarsNoTatoos said:


> Morning all, can I place all 3 negative connections on the post of battery #2 (low side), or do I need to connect them to a negative grounding bar first before connecting to battery #2? Battery number one is specifically for starting, battery #2 is for a power pole and battery #2 and #3 are for a 24 V Minn Kota. Note: I forgot to draw in the 60amp breaker. Thanks in advance.


I would use a bar...that way if something happens to either battery, you don't have to worry about it messing with your starter battery. Too many eggs in that one basket.


----------



## Vertigo (Jun 3, 2012)

The only thing on the 24 volt trolling motor circuit should be the trolling motor, two twelve volt batteries in series and and a circuit breaker. The house or starting battery(s) should be on its own circuit with a direct positive to a battery switch and a direct negative to the motor. If you have other devices to connect, use a bus bar or bars to connect them.


----------



## Flatoutfly (Jun 11, 2020)

ScarsNoTatoos said:


> Morning all, can I place all 3 negative connections on the post of battery #2 (low side), or do I need to connect them to a negative grounding bar first before connecting to battery #2? Battery number one is specifically for starting, battery #2 is for a power pole and battery #2 and #3 are for a 24 V Minn Kota. Note: I forgot to draw in the 60amp breaker. Thanks in advance.


Do not connect all 3 negative just the 2 negative of the batteries you are using to the switch, The 3rd negative will not do anything.


----------



## lemaymiami (Feb 9, 2007)

Quick, go look at what I just wrote on the previous thread... You’ll still have questions and I’ll be glad to sort it out for you... ( 2 house/ starting / electronics)


----------



## finbully (Jan 26, 2013)

1 battery - 12 volt for starting, electronics and power pole grounded to bass bar. PP & electronics are not going to run down your starting battery under normal circumstances.
2 batteries - 12 volt wired in series grounded to a buss bar, with circuit breaker to TM.
Don't ground all 3 together, a dead short on one will shut down your whole system.
You can connect to a switch like this for a backup 12 volt starting circuit:
Blue Sea Battery Switch 1-2-OFF 350 Amp | Northern Arizona Wind & Sun (solar-electric.com)


----------



## Mako 181 (May 1, 2020)

I have had one starting battery while live bating offshore. Running VHF, LORAN, live well -1 pump, bait tank 2 pumps, bildge pump, 2 electric reels on kite rods and getting into a long drift. Go to move to do another drift and no start due to low battery. Switch over to other battery, start engine, switch back to other battery or both (trying to charge low battery’s with engine alternator is hard on stator) while running to set up a new drift and it would charge while running to new drift location only to do it all over again.


----------



## finbully (Jan 26, 2013)

Mako 181 said:


> I have had one starting battery while live bating offshore. Running VHF, LORAN, live well -1 pump, bait tank 2 pumps, bildge pump, 2 electric reels on kite rods and getting into a long drift. Go to move to do another drift and no start due to low battery. Switch over to other battery, start engine, switch back to other battery or both (trying to charge low battery’s with engine alternator is hard on stator) while running to set up a new drift and it would charge while running to new drift location only to do it all over again.


Not nearly the same situation as the OP asks about. The electric reels themselves would run down a single battery of most sizes.


----------

