Posted by MarkB_MI on April 29, 2009 at 02:55:38 from (216.234.126.146):
In Reply to: Electric math problem posted by jdemaris on April 28, 2009 at 09:54:13:
Amp-hour ratings of batteries are the "area under the curve". That is, when rating your batteries, they probably didn't discharge them at a fixed currect, but rather adjusted the load for a fixed voltage as the battery discharged. Hence they are rated at "12.5 volts", which might be 20 amps when fully charged and 100 milliamps when nearly discharged. They plot the resulting current versus time curve, and measure the area under that curve. The area equals the amp-hour rating for the battery.
Now for low-current loads you'll probably get very close the the rated amp-hours. But for a high current load, the voltage will quickly drop off causing the current demand to increase and a further drop in voltage. The result is that you'll be discharging the battery much faster than the rate at which it was rated, so you can't expect to get the full rated amp-hours. I'd suggest you assume you can get fifty percent of the rated amp-hours. You might do a little better, but you probably won't do any worse.
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 ]
Today's Featured Article - Show Coverage: Journey to Ankeny - by Cindy Ladage. We left Illinois on the first day of July and headed north and west for Ankeny, Iowa. Minus two kids, we traveled light with only the youngest in tow. As long as a pool was at the end of our destination she was easy to please unlike the other two who have a multitude of requirements to travel with mom and dad. Amana Colonies served as a respite where we ate a family style lunch that sustained us with more food than could reasonably fit into our ample physiques. The show at Ankeny
... [Read Article]
Latest Ad:
1964 I-H 140 tractor with cultivators and sidedresser. Starts and runs good. Asking 2650. CALL RON AT 502-319-1952
[More Ads]
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy
TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
