Thread: Battery sparking issue....

when disconnecting a battery you should remove the negative cable first and then the positive cable !!! when connecting the battery you should put the positive cable on first then the negative cable !!! reason for this method reduce the chance of arcing !!!, hope this helps !!!

here is a good read !!!

How To Install a Boat Battery - Marine Battery Guy

First thing to do is determine source of power draw. Pull fuses on one item at a time until you figure out what is causing spark. Then from there you can determine how to approach fixing the problem. A main power switch will kill the power draw but not really solve the problem. No need for off switch on trolling motor. It should be dead when stowed unless a older Pvd2 motor. Also is it sparking on main cable to motor. Some of the newer motors that are computer controlled can have a power draw to the electronics all the time. Any draw large enough to cause a spark is going to drain battery over a long period of time.

Milliamp draw from the your newer outboard motor....normal my does the same thing.

It is sparking only on the main cable to the motor..... Not the smaller accessories cables. So the motor is pulling power all the time. Its a 2018 Mercury 115 4-stroke

Then if putting in storage I’d disconnect that cable. Has to be drawing power through the computer. Unless you experiment a battery drain issue the way you normally fish I wouldn’t waste the money on switches. I am guessing you have onboard charger and have that battery hooked to it.

Originally Posted by strmwalker

when disconnecting a battery you should remove the negative cable first and then the positive cable !!! when connecting the battery you should put the positive cable on first then the negative cable !!! reason for this method reduce the chance of arcing !!!, hope this helps !!!

here is a good read !!!

How To Install a Boat Battery - Marine Battery Guy

Whether the positive or negative is connected first makes no difference when arcing is concerned. It will spark either way.

The reason that you always do the negative first (or last) is from the automotive world where the whole vehicle is grounded, if you bump the something under the hood with a wrench nothing will happen on the negative terminal, on the positive it is a dead short and can weld the wrench in place.

OP, since that is a newer outboard, it is likely the capacitors in the engine computer. They discharge when disconnected and draw quite a bit of power when reconnected, however, once they are charged current draw is minimal. If you are not having dead battery issues, I wouldn't worry too much.

One thing you can do is connect an ammeter in series with the cranking battery, hook it up and wait a good while (30 mins to an hour) and see what the current draw is. Should be minimal, 50 milliamps or so.

Originally Posted by Atimm693

Whether the positive or negative is connected first makes no difference when arcing is concerned. It will spark either way.

The reason that you always do the negative first (or last) is from the automotive world where the whole vehicle is grounded, if you bump the something under the hood with a wrench nothing will happen on the negative terminal, on the positive it is a dead short and can weld the wrench in place.

OP, since that is a newer outboard, it is likely the capacitors in the engine computer. They discharge when disconnected and draw quite a bit of power when reconnected, however, once they are charged current draw is minimal. If you are not having dead battery issues, I wouldn't worry too much.

One thing you can do is connect an ammeter in series with the cranking battery, hook it up and wait a good while (30 mins to an hour) and see what the current draw is. Should be minimal, 50 milliamps or so.

I never had one to this day arc hooking the positive cable first and negative cable last !!! and I have been doing it that way for over 30 years !!! I must be LUCKY !!!!!

A float charger should keep up with the drain by the gps puck and the outboard computer