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Can You Make a Car Battery Last Forever by Draining It and Adding Motor Oil?

By John Rockhold


Tags: car battery myth, car battery, drain car battery,

I was told by a friend that this trick will make a car battery last forever: Run a fully charged battery until it dies. Then pour out all the water and acid in it and replace them with motor oil. Then charge the battery and it will last forever! Will this really work, or was he smoking something bad? 

Chuck Hembree 

Greer, South Carolina 

Chuck — I ran the idea by several experts who have vast amounts of knowledge and experience with batteries, auto mechanics and general transportation technology. The adamant reactions varied from "nutty" to "no place in reality" to "very dangerous." Laughs aside, the latter is the most imporant point. It's dangerous to tinker with a battery like that, especially with the acid. Don't try this at home.

— John Rockhold, managing editor. Find him on .