Battery wiring

[520vx]

Changing my batteries out for trolling motor (36v) and found a #16 Black wire from (-) on cranking battery to (-) on one of trolling motor batteries. Can onyone tell me tha reason for this wire.

[CatFan]

It's there for noise reduction in electronics.

If it's connected to any TM battery but the one with the TM negative cable on it or you have a US2 motor, it will cause problems.

[billnorman1]

If you have a three battery 36 volt system it will short out the starter battery don't hook it up. With a 4 battery system it can help solve interference and corrosion issues.

[Larry3215]

If you have a three battery 36 volt system it will short out the starter battery don't hook it up. With a 4 battery system it can help solve interference and corrosion issues.

It doesnt mater how many batteries you have on the TM side. It only matters which one of the two or three its connected to. It can only be connected from the starter battery ground to the TM battery ground that has its ground connected to the TM negative.

It also could short the TM battery depending on any common ground connections. It can certainly create huge damage from galvanic corrosion.

[texasbassdude]

Interesting trick... how does this reduce interference?

[CatFan]

Interesting trick... how does this reduce interference?

It gives the TM system and electronics system a common reference voltage. Best to include a fuse in the wire in cases something gets connected wrong.

[Larry3215]

Sometimes it helps reduce interference for the reason CatFan says, but in some cases it causes more interference and its best to remove it. Other times it makes no difference at all. No way to tell until you try it.