Some of the small chargers need to see a tiny bit of current coming from the battery or they won't work. This is done to protect against polarity reversal and short circuiting of the charger leads.

Places such as Autozone use much larger chargers that are often more sophisticated. I don't agree with them putting this on a fast charge though, because it was apparently dead flat. Total discharge is the worst thing that you can do to a battery. You need to figure out how this happened to make sure it does not happen again. Every time it does happen, is like driving another nail in that batteries coffin.

You will not get a long lifespan from it because the plates are being stripped of their material. That can only go on for a certain before you end up with a weak cell, then a dead or shorted cell. At that point, it's new-battery time.

Good explanation. Thanks. It's one of my son's tractors. He lets 'em sit without running, hot when it's hot, cold when it's cold. I hope I've got him bringing it to the barn and putting a trickle charger on it.

This Renaissance device will restore a dead battery: http://www.r-charge.com/RC_rc2a122.html
It is much more than just a charger. I had two car batteries that were dead and in my junk pile and I restored them both with this charger (which is more like a rejuvinator). Now they both are at ~12.6 volts and hold a charge.

Those are some pretty extravagant claims for a charger that costs as much as that one does. What surprises me is that this is the first time I've heard of this charger. When you consider the current "green movement", one would think that the media would be all over this charger. If it actually does what they claim it does, then someone could set up a battery rejuvenation business whereby customers could drop off their dead batteries and return a day or so later to retrieve them after paying a small fee.

I bet that I have about 20 cordless tool batteries from Milwaukee, De Walt and Makita kicking around that are in need of restoration. I've stopped using those tools because the cost of replacement batteries is just too high.

The forklift truck industry should also be excited about this technology as should every golf course that uses battery powered carts with six 6 volt lead-acid batteries in each one. Did you subject your batteries to a load test after you recharged them with the Renaissance unit?

Ahh, yes, the battery rejuvenator trick! Sounds great! Will save lots of money, after you buy it!
BUT---------When the lead on the plates inside the battery finally all fall off, your trick charger you just bought, will no longer charge that battery, nor any other one, if they are in the same condition! At that time---you can recharge that battery until yer hair falls out, and although you might get a short amount of time from the battery--it ain't gonna last! Also, the one aspirin tablet in each hole on top of the battery is a joke. Also, the dumping of the liquid inside the battery, washing it out with a garden hose, and filling it with fresh water, is an old wives tale! Bite the bullet--buy new!!

10-4 and Amen Rusty ! :)