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Frankie, I can assure you a fully-discharged battery CAN be charged with the polarity reversed, if the charger is connected with the leads swapped. I am not saying it is GOOD for the battery, or that it will always work, but it DOES happen. One instance I was involved with was some years ago, with a Deere 7700 combine. The battery went dead over winter, and my customer removed it, and carried it to his shop to recharge it overnight. Then, he carried it back to the combine, and tried to connect the cables. As the last cable was touched to the post, it sparked like a dead short. He called me to have me check out what was shorted on the combine. One way or another, after a little head scratching, I figured out he had charged the dead battery with the polarity reversed, and the alternator diodes were acting as a short when he touched the battery cable to the post. We connected a headlight to the battery with test leads, and discharged it, and then he correctly connected the charger, and charged it back up. When it was put back on the combine, all was well. Luckily, even the alternator survived. (If he had just dropped the cable in place, and not noticed the spark, the alternator would have been toasted.) I can think of at least 2 other similar instances I have seen personally, where this has happened. There is no use arguing about it, or denying it can happen. 550Doug verified it DOES happen when he got opposite polarity readings with his voltmeter.
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