Comments on: Battery Disconnect Switch

By: patrickfw

patrickfw — Thu, 10 Jul 2008 13:39:18 +0000

What I’ve seen many times at the race track (and I’ve done it myself, oops) is someone will install a battery disconnect thinking it will shut off the engine in an emergency. what really happens is the engine will keep running with power just from the alternator. This causes the alternator to start overcharging which will burn it out pretty quick. I think some alternators have kind of a built in safety for that, but not all. If you are just using it as a quick disconnect while working on the car then it’s a perfect solution.
Hope that helps. Summit does sell the type with a alternator cicuit, I believe.

By: Chris

Chris — Wed, 09 Jul 2008 21:06:17 +0000

Patrickfw, mind explaining why killing an engine with a battery disconnect switch is bad for the alternator?

By: Patrickfw

Patrickfw — Wed, 09 Jul 2008 13:09:28 +0000

Just don’t use it as an engine kill unless you want to be buying new alternators. You can buy a different model that has a disconnct for the alternator circuit. My two cents worth.

By: Adam

Adam — Mon, 07 Jul 2008 21:48:45 +0000

You can get all sorts of versions of these at any race shop, and in some race series you need specific non-sparking ones that are AHRA-approved or whatever. But yeah, they’re nice for some things- I use one on a big set of trawling motor batteries, to disconnect them when I’m not using them. Less sparking then just removing the cable, and less wear over time too.

By: Shopmonger (aka Donny B)

Shopmonger (aka Donny B) — Mon, 07 Jul 2008 20:52:26 +0000

These are great for a car that you never move. My wife has a winter car and she uses one of these. Keeps her battery from dying. Alos great fro race cars for quick pit stops (aka i broke somehitng during a race)
Or I have also used them on Drag cars for cutting the power during quick tune ups at the track.