If I wanted to charge battery...

[TobyfromMO]

back through the trolling motor plug what wire size would I need to keep things from getting to hot? I was thinking 8-10ga min. Also...will the voltage drop across 4-6' of wire effect anything?

[Big John]

This is one of those rules again, use the heavier 8 gage wire. As far as voltage drop it would be negligible in 6'.

[TobyfromMO]

Thanks John, but I have to say "NOSHIT SHERLOCK". I was looking for factual input, not one of your Mr. Obvious rules to live by.

[fishin]

Toby, how many amps is the charger? I would run the same gauge as the charger currently has which is probably 10 or 12 if it is a 10 Amp charger.

[Big John]

I guess you should not ask "Mr. Obvious" questions.

[Big John]

How far away from your battery is your motor? What is the gage of the wire running to your motor from the battery? Are you charging a 12 or 24 volt system?

[TobyfromMO]

Thanks Fishin, just so happens I got enough 10ga on hand to do that job.

John, Now I think your on to something. This would assumes that drawing amps from a battery has the same effect on the wire as charging amps into a battery.....then I should need a wire any bigger than what runs from the motor to the battery. Considering your last response along with Fishin's. My charger can put out 10 amps. The trolling motor can surely draw more than 10 amps. I think it draws as much as 25-30 amps on the high setting.

So my questions is...is drawing amps across a wire the same charging amps across a wire?

btw...it is a 12v system and the battery sits directly below the deck the trolling motor is mounted to.

[Big John]

if you are using 10 gage wire the resistance is .000999 ohms per foot of wire, so you need to know how much 10 wire you have in the circuit, then multiply the amps X resistance = volts so if you have 10 ft of wire the R= .00999 X 10A charge = .0999 Volts lost in 10 ft. V=IR

[TwoTigers]

Just buy another trolling motor plug with the short wires, tape off the unused one and clip your alligator clips from your charger to the red and black wires. Then plug it into the trolling motor plug-in. That's what I used to do before I entered the 21st century and go an on-board charger.

[fishin]

Toby,

There is a difference because the charger can only flow 10A in max. However, as you said the motor can draw considerably more amperage than the charger can provide hence the need for a larger wire feed to the trolling motor.

TwoTigers option works fine for what you're doing or you can high tech redneck it and cut the clips off the charger and solder them together. The other option is to go to BPS and buy an onboard charger for the $89 that they are currently on sale for or go steal one out of somebody's boat at the dock.

[TobyfromMO]

Since I already have a battery charger there is no way I'd buy another...I'd choose to steal one.

[Roscoe Dog]

10 gauge wire will handle 30 amps, 8 will handle 40 amps. Use the 10.

[fishin]

Toby, I would say steal one, just not the one out of my boat

Roscoe has the current handling pretty much nailed.

[TobyfromMO]

Thanks boys...

[counts]

electricity is cool