New charger designs seem to not recognize a battery that isn't polarized. An old mechanic told me you can actually change the polarity of a battery by hooking it up to a headlight and allowing it to go completely dead.

Then you just hook the charger up on on the wrong poles and let it charge. I can't imagine why or how he figured that out but a battery with a zero charge won't be recognized as a battery by the new style/designed chargers.

If you have a zero charged battery you can trick the new chargers into polarizing it by hooking up one of the poles and striking the other pole with the lead. It appears to send to send electricity through the battery for an instant. Eventually the battery will be recognized as being a battery and the charger will begin to function normally.

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