POS or NEG Battery Disconnect switch

All those parallel batteries, lol. Nice find, Don.

 

I imagine as a "battery disconnect" either side of the battery will do, but the "normal" method I have been exposed to is to switch the +pos side of the battery.

Now as a "kill switch" that has only been touched on here this is what I would recommend to prevent the back feeding as stated earlier through the alternator.

 

Shoestring, Kerry, Anderegg, this is the argument that makes sense from a vehicle electrical shut off point of view. The alternator does act like a battery, and, as stated, if the ground circuit uses the chassis and engine, the alternator ground can't really be switched.
Kerry, a lot of the electron talk, while it doesn't necessarily matter in this conversation, was just being brought up to dispute those who were saying that the electricity flowed from positive to negative and that the positive is the 'feed' side.



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Also, the positive ground comment was not 'trolling'. My car is 6V positive ground.
Now, Kerry, a question for you. With the requirement that the battery isolator be up front, from a safety point of view, it would seem to me that the battery would be better off up there as well. Is there a rule requiring the battery to be in the rear, or is it a matter of weight or lack of room up front?

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Awesome. This is why I'm here...to learn something. The positive ground setup is interesting. Are there any devices in the car that are polarity sensitive and require this per the original design? I can't think of anything that would be...unless a generator or ammeter of some type was. What year is the car? I would guess it is late 19 teens to twenties. Thanks!

 

It's a 1929 Ford. Most cars were positive ground into the late 1940's, and some British cars until the 60's. Boats may have gone even longer.

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As far as I know, GM went from 6 V pos ground to 12 V neg ground in '55. Ford and Chrysler in '56.

 

so Bob- which side do you vote for?

 

after this thread; he decided to use hand signals, carbon gas lights, hand crank and a magneto.

 

The isolator is best placed as close to the battery as possible. Any wiring between the battery and the isolator is exposed to a dead short [in an accident situation ]

Motorsport NZ [an affiliation of the FIA] requires the isolator to be at the base of the windshield on the cowl or the fender with a blue triangle and a lightning bolt decal .


The tech inspector would occasionally walk along the "Dummy Grid" and flick off all the isolator switches ,and any car still running wasn't allowed on the track.
Now because we are all seeking the elusive 50/50 weight distribution, it is common practice to put the battery in the trunk.
That is why I used a solenoid on the main starter feed , and the wire to the isolator switch has a fusible link [at the battery post]

 

^^^^^^^^^^^^^^Keerynzl, WHY are there arrows on the LEFT and RIGHT of the OFF notice? I sure would like to have things clearly marked so the fire could stop quickly. Bob

 

That is a picture I plagiarised off the 'net, from a vendor selling them.

We would buy a universal decal kit for motorsport cars, what we had to do was trim off the arrows so it showed "OFF" only

Kerry

 

THANKS! Bob

 

I'll Bet He Does Both