2-batt or 3-batt need help

jcassjr

Cadet
Joined
Sep 5, 2009
Messages
23
Just picked up a boat for my famly to have fun with and do some fishing also. Bought a trolling motor 24 volt 75 lb thrust for my 1989 maxum 20' open bow. My question is can I just add one battery to the boat battery system to get the 24v? Also bought an on board battery dual bank charger. Can I set it up this way instead of 2 seperate batteries for it? The rear of the boat has limited storage but can be done, if necessary. I don't fish a lot - mostly use it for water toys. So, the use of the trolling motor is low except for one week in sept when I go fishing for 8 days. Thank you.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: 2-batt or 3-batt need help

DO NOT use the engine starting battery as one of the batteries for the trolling motor. You will at one time or another kill it to the point where you can't start the engine. Trolling motors draw a lot of current so you need two "deep cycle" batteries - not starting batteries. You need an on-board charger that has two outputs to charge the troller batteries when at the dock or at home. On-board chargers get plugged into AC power -- they do not operate from the engine charging system. The engine will keep the starting battery topped off.
 

jcassjr

Cadet
Joined
Sep 5, 2009
Messages
23
Re: 2-batt or 3-batt need help

i will do that then the last thing i want is get stuck with a dead batt. can i use the first batt. of the 24v to pull off 12 v for acc.
 
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Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: 2-batt or 3-batt need help

I would recommend you use the battery that has the ground connection for the trolling motor as the source of 12V for accessories. If you use the battery that actually feeds the motor as the source, you run the risk of an accidental gound situation that will fry any 12 volt electronics. If you use the first batter (the one feeding the troller) be certain you also ground at that battery. Here is how it's done.

12Vfrom24Vsystem.jpg
 
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