Posted by Paul Cook on Tuesday, April 30, 2002 at 9:28PM :
In Reply to: Prefered voltage 6 or 12 posted by Bob Cocivi on Tuesday, April 30, 2002 at 4:47PM :
I am converting everything to 12V. 6V works just fine. The real problem is that few people know how to jump a 6V system with 12V. Wrong way is one guy hooking cables from 12 to 6. When you turn on ignition switch, the fuel gauge and maybe the coil are fried. A real dumb way is to do this with the lights turned on and blow them all. Remember there may be a dome light with a door switch. And don't rest your foot on the brake pedal and get the brake light bulbs.
Ask yourself how a guy who started driving in the 50's when 12V was new learned these things. Momma said I was the smartest guy in the world. Actually she said I should learn from my mistakes and I made so many I should have wised up by then.
The only correct way is connect the 12V "hot" to the 6V "hot". Then have a buddy stand by with the 12V ground jumper cable. Pay attention to which is ground since some 6V systems were positive ground. Here, the 12V jumper cable is ground relative to the 6V vehicle. Driver turns of all 6V lights and anything else that is controlled separate from the ignition switch. Driver hits starter on 6V vehicle. While the whole starting load is on the 6V system, the buddy touches the 12V ground to the 6V ground. Best to touch the frame or other good ground - not the 6V battery post. Buddy removes the 12V ground the instant the 6V vehicle fires OR the driver releases the starting load.
When you jump 12V with 12V, the only wrong thing is reversing polarity.
Bottom line: If you have a situation where you frequently may have to jump off a 6V with a 12V by yourself, convert them all to 12V. If you will always have a buddy there to help, 6V is okay.
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