Battery Shut Off

L78 Nova · 09-08-2010, 10:19 AM

I'm installing a battery cut off switch (double pole) on a 72 chevy Nova. I plan to use a relay (up front) to interrupt the primary circuit of the alternator. Which wire should I interrupt the Blue or White ? The cut off switch will power the relay.
Thanks for you help....
Gary

Run to Rund · 09-08-2010, 11:21 AM

You might check out the several threads on yellow bullet. The summary of "wisdom" contained in them seems to be this: Run a heavy output wire from the alternator to the battery side of the cutoff switch (there is a chart at the top of their electrical forum; 20 ft at 60 amps max for 4 gauge). Run the MSD power to the battery directly. Solder and crimp connections. The reasoning is this: The alternator (brushes) make the output noisy so don't power the MSD there. So long as the "trigger" is cut off by the switch, the car will stop running. Don't cut the alternator with the switch or you can blow the diodes. I ran 2-0 gauge from the battery to the switch and from the switch to the front (junction block). Hope this helps.

L78 Nova · 09-08-2010, 12:06 PM

My thinking was... trying to get away from the large gauge "hot" lead all the way to the back. The alternator then has to charge through that entire length The main harness power feed (on horn relay) would also no longer be fed direct from the alternator so all running load would draw entirely through the starter feed (rather than paralleled with the alternator feed).

I did blow my regulator once already with the single pole cut off.
Thanks for your input, I will check at yellow bullet also.

09-08-2010, 10:19 AM	#1
L78 Nova Junior Member Join Date: Dec 2009 Location: Winnipeg, MB Posts: 92 Likes: 249 Liked 23 Times in 13 Posts	Battery Shut Off I'm installing a battery cut off switch (double pole) on a 72 chevy Nova. I plan to use a relay (up front) to interrupt the primary circuit of the alternator. Which wire should I interrupt the Blue or White ? The cut off switch will power the relay. Thanks for you help.... Gary

09-08-2010, 11:21 AM	#2
Run to Rund Senior Member Join Date: Sep 2007 Location: Henderson, NV Posts: 583 Likes: 8 Liked 54 Times in 27 Posts	Re: Battery Shut Off You might check out the several threads on yellow bullet. The summary of "wisdom" contained in them seems to be this: Run a heavy output wire from the alternator to the battery side of the cutoff switch (there is a chart at the top of their electrical forum; 20 ft at 60 amps max for 4 gauge). Run the MSD power to the battery directly. Solder and crimp connections. The reasoning is this: The alternator (brushes) make the output noisy so don't power the MSD there. So long as the "trigger" is cut off by the switch, the car will stop running. Don't cut the alternator with the switch or you can blow the diodes. I ran 2-0 gauge from the battery to the switch and from the switch to the front (junction block). Hope this helps.

09-08-2010, 12:06 PM	#3
L78 Nova Junior Member Join Date: Dec 2009 Location: Winnipeg, MB Posts: 92 Likes: 249 Liked 23 Times in 13 Posts	Re: Battery Shut Off My thinking was... trying to get away from the large gauge "hot" lead all the way to the back. The alternator then has to charge through that entire length The main harness power feed (on horn relay) would also no longer be fed direct from the alternator so all running load would draw entirely through the starter feed (rather than paralleled with the alternator feed). I did blow my regulator once already with the single pole cut off. Thanks for your input, I will check at yellow bullet also.