Trolling Motor Battery Configuration

Thinking about adding a trolling motor to my Tidewater 180. At this point I haven’t determined whether it needs to be 12V or 24V. I’m guessing 24V. My boat came with one battery and I added a Blue Seas switch and a second battery.

With a 24V trolling motor, what’s the best way to make that work battery wise ? I wouldn’t mind putting one more battery under the console for a total of three but I would not be willing to add two for a total of 4 batteries. Would I need an additional switch or a different one ?

Thanks,
Greg

Unless you can start your outboard with a rope, don’t try running a T M off your cranking battery! You need dedicated battery for cranking and another pair to operate the 24V. I would recommend also a house battery to run the electronics ,lighting pumps ect. and be switched with the cranking battery. What does Larry and Chris think?

You need to have an isolated battery system for your tm. With that size boat you could get away with a 12v but a 24v is ideal for longer run time and more thrust. Go with 4 group 24, or a single group 27 for the motor and 2 24 for the tm. Seperate switches. Add an onboard 3 bank charger and keep on charge before each trip.

Scout 185

You can also make 2 small jumper cables in case you ever need the juce from the tm to the main battery. Just keep them in your dry box.

Scout 185

quote:
What does Larry and Chris think?

Not speaking for Chris, just me. I think an 18’ boat needs a 24V trolling motor, with the batteries completely isolated from the starting and house 12V battery system, and engine alternator charger. They should be 2 completely separate systems and not be connected in any way except for the ground wires. An onboard charger is the ideal way to go.

Capt. Larry Teuton
Swamp Worshiper

Thanks guys. I appreciate all the info.

2013 Tidewater 180CC
115 Yamaha

24 volt trolling motor for that size boat. You will need one “Crank” battery and two “Trolling Motor” batteries. Install a battery selector switch with positions as follows: Off - 1 - 2 - 1+2. There are three terminals on the battery selector switch. Terminal #1 connects to the positive post of the “Crank” battery. Terminal #2 connects to the positive post of one of the trolling motor batteries. The “common” terminal connects to the negative posts of the “Crank” battery and the “Trolling Motor” battery that is connected to the #2 terminal of the battery selector switch.

The switch is left in the #1 position at all times. If your crank battery gets weak and is unable to crank the outboard motor, then you simply turn the battery selector switch to the 1+2 position. This ties the two batteries together in parallel, and provides power from both batteries to crank the motor.

This negates the need for a fourth battery. This system is commonly used in boats.

Sounds like the solution I’m looking for bkdraper62. I already have the switch and would avoid having 4 batteries. Thanks !

2013 Tidewater 180CC
115 Yamaha

I agree with larry with one minor exception
you do need 2 separate systems, but you can still easily get by with 3 batteries
2 trolling motor batteries and 1 starting batter, but you can use an emergency parallel switch to steal power from one of your trolling motor batteries to start your engine in an emergency. we have done this many times on different boats, and it works great.

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Thanks Chris. I would definitely want to use 3 batteries instead of 4 without giving up a backup to my cranking battery.

2013 Tidewater 180CC
115 Yamaha

quote:
Originally posted by bkdraper62

24 volt trolling motor for that size boat. You will need one “Crank” battery and two “Trolling Motor” batteries. Install a battery selector switch with positions as follows: Off - 1 - 2 - 1+2. There are three terminals on the battery selector switch. Terminal #1 connects to the positive post of the “Crank” battery. Terminal #2 connects to the positive post of one of the trolling motor batteries. The “common” terminal connects to the negative posts of the “Crank” battery and the “Trolling Motor” battery that is connected to the #2 terminal of the battery selector switch</font id=“red”>.

The switch is left in the #1 position at all times. If your crank battery gets weak and is unable to crank the outboard motor, then you simply turn the battery selector switch to the 1+2 position. This ties the two batteries together in parallel, and provides power from both batteries to crank the motor.

This negates the need for a fourth battery. This system is commonly used in boats.


bk
I’m pretty sure if you do this, the moment you move the selector from the off position, REALLY bad things are going to happen
at a minimum you are going to melt the selector switch, and possibly cause the batteries to explode and or catch the boat on fire</font id=“red”></font id=“size4”>
you will be connecting the positive from 1 and 2 to the negative from 1 and 2, unless I’m completely misunderstanding what you are saying

I think I know what you are trying to suggest, you just don’t have the wiring correct.

you need battery 1 (crank) positive to go to position 1 on the back of the switch
you need battery 2 (trolling) positive to go to position 2 on the back of the switch
your positive cable going to the motor connects to “common”

Yep. Bad things will happen. I have fried a perko before. Not very fun.

Scout 185

My bad!
Chris V you are correct!

A picture is worth a thousand words. Hopefully this link works!

http://www.mbcboats.com/FAQs/FAQ_files/image127.jpg

I appreciate the replies. If I decide to do this, I’ll be contacting a professional to do the wiring !

2013 Tidewater 180CC
115 Yamaha