Question:
I have a 24 volt trolling motor system currently in my boat, can I use one of the batteries as a starting battery and for my electronics as well? Looking to save weight and free up some space by not having that 3rd battery.
Thanks!
No. It will cause that one battery to lose voltage quicker than the other. Your t-motor draws from both batteries at the same rate until one is dead then it stops. Your one with the starting and electronics will die before the other causing the motor to stop prematurely.
You can but will run into issues such as graph interference and the possibility of draining your starting motor battery to the point of not being able to start your main motor.
I would not recommend doing what your thinking.
Ron
Hmmmm. That’s an interesting one.
Since the 24 volt system is two 12 volt batteries wired together in series to achieve 24 volts, you can’t just connect your starter wires to the terminals of your 24 volt array or you’d be pushing 24 volts to a 12 volt starter.
Maybe someone has an elegant pre-packaged solution that allows you to isolate 12 volts just to the starter? I’ve never heard of this, but like everything else, it may have already been thought of.
Second problem I see is that some outboards are very “fussy” when it comes to available amperage. They won’t lift a finger to start your outboard unless you have a full charge available. So if you start sucking down amps using your electric motor, pretty soon you may find that your starter won’t engage.
Again, maybe somebody already has a pre-fab way of doing what you’re trying to do.
Grouse
I think it might depend on how much you’re drawing from one of them, too. I run my front depth finder/graph off one of my 2 batteries I use for my 24 volt trolling system. But that’s all I run off it (besides the trolling motor). Pretty tiny draw, so I haven’t noticed any impact on the trolling performance. But I don’t think I’d use it for any more than that.
You always keep your starting battery out of the 24 volt system. Unequal batteries will cause all sorts of trouble for the 24volt system. Also if you are using a Fuel injected motor they are sensitive to voltages IE Etec, Optimax. Using the trolling motor could draw the batteries down enough that you may not have your motor start even though your trolling motor may still work as well as your electronics etc. Dedicate a starting/electronics battery separate from the 24 volt system go with 3 bank on board charger and charge after every use and you can get 3 or 4 season of heavy use out of the 24v system. Proper charging and battery maint is critical
Mwal
Mwal
You can run off of your negative side of the series circuit and achive 12 volts with out any problems but I would not reccomend running your main motor off of it encase your troller runs it to low to start your motor. I have done this on a few of my boats to run 12 volt accessories but never with a main motor. I can deal with a graph dieing due to a dead battery but would always want my motor to start.
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Hmmmm. That’s an interesting one.
Since the 24 volt system is two 12 volt batteries wired together in series to achieve 24 volts, you can’t just connect your starter wires to the terminals of your 24 volt array or you’d be pushing 24 volts to a 12 volt starter.
Maybe someone has an elegant pre-packaged solution that allows you to isolate 12 volts just to the starter? I’ve never heard of this, but like everything else, it may have already been thought of.
For 12 volts in a 24 volt system use the positive and negative from the same battery to get 12 volts it does not matter how they are wired.
like mentioned it can be done but it isn’t recomended.
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Hmmmm. That’s an interesting one.
Since the 24 volt system is two 12 volt batteries wired together in series to achieve 24 volts, you can’t just connect your starter wires to the terminals of your 24 volt array or you’d be pushing 24 volts to a 12 volt starter.
Maybe someone has an elegant pre-packaged solution that allows you to isolate 12 volts just to the starter? I’ve never heard of this, but like everything else, it may have already been thought of.
For 12 volts in a 24 volt system use the positive and negative from the same battery to get 12 volts it does not matter how they are wired.
You should always use the battery that has the negative lead of the trolling motor going to it. If you use the other battery and you have one of your 12 volt accessories accidently ground out to the boat (tin boats) you will now get 24 volts to your 12 volt accessory and you better hope your fuse is quick enough to pop.
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For 12 volts in a 24 volt system use the positive and negative from the same battery to get 12 volts it does not matter how they are wired.
OK, I think I’ve got you. Even if you have the batteries hooked up in series for the trolling motor, if you just put the leads that go to the outboard starter on the + and – of of the same battery, you get 12 v. That would make sense.
Had to draw a picture for myself to figure that one out.
Grouse
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Hmmmm. That’s an interesting one.
Since the 24 volt system is two 12 volt batteries wired together in series to achieve 24 volts, you can’t just connect your starter wires to the terminals of your 24 volt array or you’d be pushing 24 volts to a 12 volt starter.
Maybe someone has an elegant pre-packaged solution that allows you to isolate 12 volts just to the starter? I’ve never heard of this, but like everything else, it may have already been thought of.
For 12 volts in a 24 volt system use the positive and negative from the same battery to get 12 volts it does not matter how they are wired.
You should always use the battery that has the negative lead of the trolling motor going to it. If you use the other battery and you have one of your 12 volt accessories accidently ground out to the boat (tin boats) you will now get 24 volts to your 12 volt accessory and you better hope your fuse is quick enough to pop.
This is correct and it does not matter if the boat is tin or glass you will get 24 volts out of the battery that has its negative terminal connected to the other batteries positive terminal.
Seems I better just stay with the 3 batteries. Thanks for all the posts! 
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