How to set up 36-volt system that can run trolling motor and crank outboard
A 36-volt trolling motor is the only way to go. They have lots of power but sip at the batteries, so you rarely have to worry about losing steam during a hard day on the water.
Of course, the only problem is that you have to have three batteries. That usually means most anglers have four batteries in their boats — one that cranks the outboard and runs all the electronics, and three dedicated to the trolling motor.
That can make for a crowded bilge area, and if you’re like me you don’t really have the room to spare.
So what’s an angler to do?
Well, you can ditch the cranking battery and use a three-bank series that cranks the main engine, runs your electronics and powers the trolling motor.
This is the system I’ve used for years. I have plenty of power, and save money because quality marine batteries cost hundreds of dollars each.
But how can this system work?
While it sounds like you’re asking for trouble without a dedicated cranking battery, keep in mind that the battery attached to the outboard charges as you run from spot to spot, so you don’t really have to be concerned about that. I’ve never had any problems with cranking, even at the end of the day.
With that out of the way, the trick to ensuring you’re sending 36 volts of electricity to the front of the boat is pretty basic.
1) Hook up your cranking and electronics wiring to the cranking battery as you normally would.
2) Run a battery cable from the positive of the cranking battery to the negative post of the second battery.
3) On the second battery, use a short cable to connect the positive post with negative post of the third battery.
That creates a 36-volt system. Of course, if you are more comfortable keeping a dedicated cranking battery, just ignore the first step and cross-connect your three trolling batteries exactly as stated above.
All that’s left is to connect your trolling motor. Here’s how to complete the circuit:
1) Attach the trolling motor’s negative wire to the negative post of your No. 1 battery (the cranking battery).
2) Attach the trolling motor’s positive wire to the positive post of the No. 3 battery.
