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From: raoul@eplunix.UUCP (Nico Garcia)
Newsgroups: sci.electronics
Subject: Re: Hi-capacity nicads?
Message-ID: <951@eplunix.UUCP>
Date: 12 Oct 90 16:03:18 GMT
References: <34658@cup.portal.com> <32999@nigel.ee.udel.edu> <1990Oct12.014312.11034@amd.com>
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Organization: Eaton-Peabody Lab, Boston, MA
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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