Disconnecting/reconnecting battery

[JRW160]

In a car, the chassis is the ground. If you decide to disconnect the positive first, and your wrench or ratchet touches the chassis while touching the positive terminal, it's just like connecting the two terminals of the battery together. You will see sparks at the least.

If you disconnect the negative cable first, which is already connected to the chassis, there is no risk.

It probably doesn't matter as much in a boat since the "chassis" that the ground cable connects to is the engine block and is usually pretty far away from the battery terminal.

[96prostar190]

Gotcha, well I guess it makes sense why they did it the way they did then! Thanks guys!

[bturner2]

Most places I know of that offer indoor storage require the batteries to be removed before coming in the building. This reduces the risk of fire (no battery = no electrical fires).

I was told to disconnect the negative lead to eliminate arcing and the chance of battery drain due to a possible ground differential. A corroded or poorly connected ground can create a circuit that will slowly drain a battery as one side will look more positive and thus create a voltage path or voltage leak. This is why it's important to tie all the grounds to a common point when wiring. When I installed my dual battery system one of the last checks I did was put a volt meter between the ground posts from the main ground terminal post and the remote ground bus in the dash to ensure they were at zero. Anything more than zero indicates a ground potential difference which can cause noise in the system as well as a drain on the battery. At least that's how it was explained/taught to me.

[96prostar190]

Thanks man!

[east tx skier]

I have a battery cutoff switch. I turn it off when the boat is not in use, including longterm storage. I charge it up at winterization and put it on a charger on the lowest setting before recomissioning in the spring. It does not lose much charge over layup.

[96prostar190]

Originally Posted by east tx skier

I have a battery cutoff switch. I turn it off when the boat is not in use, including longterm storage. I charge it up at winterization and put it on a charger on the lowest setting before recomissioning in the spring. It does not lose much charge over layup.

I thought about doing that too... Good idea, thanks!

[east tx skier]

I did it because I had a draw in the electrical system that was slowly draining my battery each summer. The switch was cheaper and easier than chasing the ghost current.

[96prostar190]

Originally Posted by east tx skier

I did it because I had a draw in the electrical system that was slowly draining my battery each summer. The switch was cheaper and easier than chasing the ghost current.

I like! Not a bad idea at all.

[lake]

I have a Prostar 214 that will draw down over time as well. I've been pulling the cable off every time but considered a battery cutoff switch. I've seen these are common in larger boats. I think Perko is the most popular brand. Is that what you installed?

[east tx skier]

Yes. I had my boat in for something and the dealer installed the switch for me. I have been very pleased with it and no more draw issues (obviously) for the last two years since installing it.