Battery hookup

[BLANESENN]

Presently have a 24v system for tm wanting to go to a 36v tm already have (3) in boat (2) for tm and (1) for elctronics, cranking and the such.I dont really have the rm for another battery can i run all my stuff off what i already have or do i need to make rm for another battery?

[Bassnailer]

You need to have dedicated batteries for your trolling motor, whether its 2 for a 24 volt system of 3 for a 36 volt system. The problem with putting your starting and house battery (whether they are the same battery or 2 separate batteries) in the circuit with your trolling batteries wired in series, is the load distribution. The shared battery will always be taxed more than the others in the circuit, which will cause the other two to drain as they try to level the voltage. Batteries wired in series need to all be the same make, model and age, and are to be treated as one battery with multiple cells. Also, you should not mix a cranking battery with a deep cell battery in a series circuit either. Sure, it would work, but you would wear out all your batteries very quickly.

[BLANESENN]

Thanks

[wmitch2]

Look at the Troll Bridge.

http://www.yandina.com/troll24info.htm

[pavi69]

Guys on the BASS tour ran three batteries for years with 36 volt troll motors. Most boats did not have room for four large batteries when 36 volt troll motors first became the thing to have. This was before they started running four 12" screens. So it really depends on how many electronics you are running.

[jacob461]

I ran a 101 minn Kota off my cranking battery for about a year with two 787 Humminbirds. When I upgraded my console unit to a helix 10 I started killing my cranking battery by lunch every day. I added a fourth battery and don’t have to worry about it anymore.

[Jonestrollingmotor]

You need to have dedicated batteries for your trolling motor, whether its 2 for a 24 volt system of 3 for a 36 volt system. The problem with putting your starting and house battery (whether they are the same battery or 2 separate batteries) in the circuit with your trolling batteries wired in series, is the load distribution. The shared battery will always be taxed more than the others in the circuit, which will cause the other two to drain as they try to level the voltage. Batteries wired in series need to all be the same make, model and age, and are to be treated as one battery with multiple cells. Also, you should not mix a cranking battery with a deep cell battery in a series circuit either. Sure, it would work, but you would wear out all your batteries very quickly.

A series circuit will not try to "level" the batteries. The only problems with running a 3 battery system is the cranking battery (the one you depend on to get you home) will discharge quicker than the other two and you can't jump from the cranking to one of the trolling without disconnecting wires since they are series wired. Also, with the higher end, more sensitive electronics you run the risk of getting interference in the depthfinders. If you're running a US2 transducer, you cannot do it as the US2 unit cannot share a battery without risk of shorting the electronic unit back through the transducer. If you do decide to do this, make sure the negative of the trolling motor is connected to the negative of the cranking and the others wired accordingly. This is to prevent electrolysis. Personally, I suggest making room for the 4th battery.
John

[Bassnailer]

I was trying to over simplify things a bit rather than go into the physics of load distribution, discharge, and overcharge among uneven cells, but the experts caught me! The jist of it is the same though, running your starting battery as the third battery in a 36 volt series circuit will work, but it is not ideal and will lead to shorter battery life for all your batteries.