Car Talk

July 1997

Dear Tom and Ray:

I have received a battery charger as a gift. It has the following settings on it: 6-volt/6 amp; 12-volt/2 amp; 12-volt/6 amp. I have a 1982 Oldsmobile, a '77 Chevy pickup truck and a Snapper rider mower. Which of the above settings should be used to charge the batteries on each of these vehicles? -- Bob

Tom: Well, for the first two vehicles, the Olds and the Chevy, you should [redcar.gif] use the 12-volt/6 amp setting. The first number, the voltage, is determined by the battery. And all modern cars use 12-volt electrical systems.

Ray: The second number, amperage, is a measure of how much electricity can flow through the charger's wires at any given time. And even your highest setting, 6 amps, is not very much. A 6-amp charger would take all night to transfer enough electricity to charge your car's battery. That's why they call your device a "trickle charger," because the electricity trickles in slowly.

Tom: It'll work perfectly well overnight, but it's not strong enough to provide an instant charge to a dead battery. For comparison, the charger in our garage is 12-volt/100 amp! That'll charge a dead car battery in an hour or less -- about as long as it takes to have your shirts Martinized.

Ray: As for your riding mower, I don't know for certain what kind of electrical system it has. Many of them use 12-volt systems, but without knowing the age of the mower, I can't say for sure. The voltage should be written right on the battery (or you can always call the company to be sure). And as long as the voltage is set correctly, I think either amperage setting would be OK.

Tom: But just to be safe, have your brother make the last connection to the terminal. Good luck, Bob.

Don't get stuck with a lemon. Be an informed shopper. Read Tom and Ray's guide "How to Buy a Great Used Car: Secrets Only Your Mechanic Knows." To order, send (check or money order) to Ruin, P.O. Box 536475, Orlando, FL 32853-6475. You can also order online.

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