How do I install 2 batteries for 24 volts for new motor?

Half Fast

Cadet
Joined
Nov 27, 2004
Messages
17
I just ordered a new Minn Kota auto pilot trolling motor from Cabela's & want to know how to hook it up to two new batteries in the front of my boat. It's a 20 foot 1978 Searay with a 350 Chevy engine & Mercruiser 260. It has one starting battery & is already heavy enough in back. Do I need a battery isolator switch so that I can charge both batteries off the engine alternator or can that even be done as that will be charging 3 batteries while the motor is running? Will this informatin come with the new motor? Thanks, HF.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: How do I install 2 batteries for 24 volts for new motor?

For a 24V trolling motor, connect the + terminal on battery #1 to the - terminal on battery #2. The + terminal on battery #2 goes to the + terminal for the motor. The - terminal on battery #1 goes to the negative terminal for the motor. Deep cycle batteries don't like to be left in a partially discharged state and even with the higher output alternator on your I/O engine, short runs will not keep those batteries topped off. Buy two identical deep cycle batteries -- the largest that will fit the available space. I would also install a good onboard charger and plug in at the dock. The less complex equipment and wiring you have on a boat the more reliable it is (but that's just my opinion). For switches, isolators, and wiring set ups, do an online search for "battery switch wiring". There are lots of options.
 

Richard Petersen

Senior Chief Petty Officer
Joined
Dec 17, 2004
Messages
778
Re: How do I install 2 batteries for 24 volts for new motor?

The 350 V8 will HELP to recharge the trolling battery if your running time is less than your trolling time. V8 puts out at least 40 amps. per hour above 2,000 rpm. The above assumes you troll on full speed.
 
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