Re: battery polarity

Posted by Bob on May 14, 2006 at 11:31:39 from (64.21.249.40):

In Reply to: Re: battery polarity posted by frankiee on May 14, 2006 at 10:39:48:

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.

Replies:

Add a Reply Name: E-Mail: Subject: Comments: Optional Link URL: Link Title: Optional Image URL: Email Notification: If you check this box, email will be sent to you whenever someone replies to this message. Your email address must be entered above to receive notification. This notification will be cancelled automatically after 2 weeks.

TRACTOR PARTS	TRACTOR MANUALS

We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]