Technical Necessity of Master Battery disconnect Swithch

Those green knob gigs, take a close look. It's a mere 1/4-20 thread that makes the contact. I can't say I've ever seen one fail in normal use, but a guy was grinding away on his starter years ago and I watched the nylon insulator melt. Just sayin...

 

I think the nylon is there to generate smoke, so you'll know something is wrong

 

What the hell kind of talk is THAT!??!?!

 

It's a strange car...I like the old stuff on it, and the old look, and making it go faster would make me have to change the appearance in ways I don't want. I won the jacket, it went fast enough. Now it's just fun.

 

Since it has been brought up, if you have to have a switch per NHRA the switch has to be on the Positive side, not the ground.

 

Good point, there are a bunch of rules about how NHRA wants things done, if you're going racing, get the rule book.

 

If you are using as a safety cutoff as well as a battery disconnect/theft deterrent and are running an alternator you need a 4 post switch like this. Speedway and Summit and the likes have them for 25-45 bucks.

 

NAPA sells a heavy duty battery terminal disconnect. It is the screw type, but built rugged enough to be used on 6-volt systems. I have one on all my vintage cars. I have them on the ground posts of the batteries. I use them for safety as the cars are parked in the garage and I do not want an electrical fire. The NAPA part number is: 728218. The price is $21.48, list. Well worth it for the peace of mind.

 

Do the small posts power the ON FIRE light? Bob

 

The small posts de energize the alternator, or the engine will continue to run off the alternator. I will try to find a wire diagram.

 

That is just like the one I bought, how long will it take for someone to post that it is the wrong one to use?

 

Wish somebody made a good 'un. The idea is OK, execution poor.

 

Thats some GREAT meme Rak!!!

 

Well, I've had four of those "green knob, or black knobs" fail. One on my on topic 55 'bird, two on an OT LT1, and one on an OT Miata, with a battery smaller than a 4 pack of hard lemonade. This thread gives me some good alternatives. Thanks.

 

Use the Moroso one in my truck, been there for 16 years now. I shut it off whenever I leave the truck, either in the garage , at the store, or at a show. The first Walmart battery I had lasted 13 years, guess shutting off extended it's life, hope the new one lasts as long!

 

falcongeorge: thanks, can't remember where I got it from but since replacing my flathead with a SBC it fits my at***ude when the abuse starts about it!