FlipBoard

Welcome to our new Magazine format! All new content will now be brought to you in this easy, new format. All our older content can still be found by scrolling below. Simply click the ">" to start the magazine and navigate via your arrow keys.

Wednesday, May 13, 2009

Batteries Part 5 Lead-acid

Lead-acid batteries are heavy, don’t hold as much power as even a NiCad, and don’t tolerate complete discharging. Even a marine deep-discharge battery can only handle 50 or so cycles before failure, and a car battery will fail after only a few times. They use toxic materials, are nasty dirty batteries, and a pain to deal with. So, why do we still use so many of them?
Lead-acid cells have a voltage of 2.1v fully charged, and have a very level discharge curve, a discharged lead-acid cell will have a voltage of 2v. Lead-acid have a charge efficiency of 60%, just 3/5 of the power that you put in comes back out. The normal configuration is to have them in a common case to produce either 6v or 12v. Lead-acid batteries can discharge at a very high rate, almost as good as a NiCad. Their real strengths are their insensitivity to charge and their high shallow cycle rate. Lead-acid cells can be charged with a basic constant-voltage charger, fast or slow, they just don’t care. Trickle, fast, however they get fed power, they take it. Also, as long as they don’t get discharged more than 20%, they can provide thousands of cycles. Finally, a lead-acid battery is better than just about any other type at low temperature operation (believe it or not).
Lead-acid: cheap starter batteries. Any other use is suboptimal.


Original: http://arizonapreppersnetwork.blogspot.com/2009/04/batteries-part-5-lead-acid.html