I did several searches and can't see any answer. What is the difference/advantage of disconnecting the Negative battery cable over the winter versus the Positive?

thanks,
phil

 

Just in case your wrench accidently grounds out while disconnecting it and becomes an arc welder in your hands.

 

I have had this happen, and it is not fun.

 

It sure does make you jump though.

 

And if you are wearing any rings that make conact, big ouchy. My old man now has a permanant wedding band.

Always ALWAYS disconnect the negative first.

 

haha, i know a guy who did that with his wedding ring, besides almost burning his ring finger off, he had a big knot on his head the next day

best thing to do, don't wear jewelry of any kind when your working on a car.

 

hah. yea. You disconnect the negative cable because your car has already broken the circuit (for the most part) in various switches and relays and while the car is off, there is very little if any current moving through the nagative cable to the chassis. There is no chance of a short circuit unless you touch the postive terminal at the same time. So disconnecting it isn't going to do anything bad. This wouldn't be the case if you were trying this while the car was running. However, the battery while still having the negative connected, can complete a short circuit if you disconnect the positive cable and accidentally touch any part of the chassis. This would discharge more than enough current to make you have a bad day.

There is no reason why this is done in winter as opposed to any other season, It should be done all the time.

If you're asking why disconnect the battery over a winter storage period, because there are devices that have power in the car all the time. If you wish to keep your battery from deep cycling you'll want to disconnect it. You'll also want to probably put some fuel stabalizer in the gas tank and run it for a bit otherwise you'll be having a bad day come spring.