perley@galaxy (Donald P Perley) (10/11/90)
>In article <34658@cup.portal.com> schuster@cup.portal.com (Michael Alan Schuster) writes: >>"AA" penlight size nicads have gone from 450 mAh to 700, and there are >>even 750's available at high prices. Could anyone post where in this range the commonly available cells fall, like GE and Radio Shack? The rating was noticably missing on the packs of RS cells I recently bought. -don perley - ke2tp perley@trub.crd.ge.com
phil@brahms.amd.com (Phil Ngai) (10/12/90)
In article <12634@crdgw1.crd.ge.com> perley@galaxy (Donald P Perley) writes: |Could anyone post where in this range the commonly available cells |fall, like GE and Radio Shack? The rating was noticably missing on |the packs of RS cells I recently bought. They probably need to be charged for 14-16 hours. Take the charge current and multiply by 10, that's the capacity. That also gives you an idea of their efficiency as an energy storage system, ignoring the difference in voltage between charging and discharging. -- The Bill of Rights isn't perfect, but it's better than what we have now.
bill@videovax.tv.tek.com (William K. McFadden) (10/12/90)
>Could anyone post where in this range the commonly available cells >fall, like GE and Radio Shack? The rating was noticably missing on >the packs of RS cells I recently bought. The capacity is usually printed on the cell, although it may be obscure (e.g., "charge at 50 mA for 14 hours," which means it's a 500 mAH cell). From the RS catalog: SIZE CAPACITY (AH) N 0.150 AAA 0.180 AA 0.600 9V (7.2V, actually) 0.065 C 1.200 D 1.400 High capacity C 1.800 High capacity D 4.000 -- Bill McFadden Tektronix, Inc. P.O. Box 500 MS 58-639 Beaverton, OR 97077 bill@videovax.tv.tek.com, {hplabs,uw-beaver,decvax}!tektronix!videovax!bill Phone: (503) 627-6920 "The biggest difference between developing a missle component and a toy is the 'cost constraint.'" -- John Anderson, Engineer, TI
raoul@eplunix.UUCP (Nico Garcia) (10/12/90)
In article <1990Oct12.014312.11034@amd.com>, phil@brahms.amd.com (Phil Ngai) writes: > They probably need to be charged for 14-16 hours. Take the charge > current and multiply by 10, that's the capacity. That also gives > you an idea of their efficiency as an energy storage system, > ignoring the difference in voltage between charging and > discharging. Most gel-cells and lead-acids use rating/10 as their maximum charging current: I don't know if that's true for NiCads. There is also a voltage drop with discharge, which can affect useful lives. However, most of the charge that goes into a battery comes right back out with discharge. The charge losses are in the leakage discharges, which varies with things like packaging and air humidity and temperature. The significant losses, however, are the voltage differences in charge vs. discharge. These are due to resistive losses, much the larger problem for batteries. So charge differences are not significantly different: the efficiencies are dominated by voltage differences. -- Nico Garcia Designs by Geniuses for use by Idiots eplunix!cirl!raoul@eddie.mit.edu