Subject:
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Re: Charging batteries
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Newsgroups:
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lugnet.robotics
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Date:
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Tue, 13 Oct 1998 15:12:40 GMT
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Viewed:
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1474 times
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Eric Brok wrote in message ...
> Our institution (a school) considers to purchase two Mindstorms sets for
> students to work with. I'm looking for the best way to deal with batteries
> in such a setting. I have seen some posts mentioning some concerns, but
> would like to have some more advice, like:
> - are NiCad the best and/or only rechhargable batteries
NiMH is also an option. They are coming down the prices of NiCad (about
$5/cell right now). The average NiMH AA cell has a greater capacity then
the average NiCad cell (1300mah vs about 850mah).
> - are quick-chargers better or worse; depending on what?
Quick chargers which make some effort to sense the state of the battery are
much better then slow dumb chargers or timed quick chargers. Its hard to
find these in AA size though. The only one that I know of is my by Olympus
for digital cameras. http://www.necx.com sells it (under digital camera
accessories). Its about $50 including 4 AA batteries, so you'd need 3 of
them for two Mindstorms robots. It charges 4 batteries in about 2 hours.
It monitors both cell temp and voltage to determine when to stop charging
the cells. This makes the cells last much longer, because they never
overheat.
> - do NiCads have a 'memory effect'?
Memory effect is for the most part a myth. 99% of the damaged NiCad cells
out there were damaged by overcharging them and causing them to overheat.
For more information on this subject check out the article on battery
technology at http://www.sheldonbrown.com/harris (its in the set of articles
about bicycle lighting). This is a bicycle oriented site, but the article
is short and good reading.
alex
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Message has 1 Reply:
 | | Re: Charging batteries
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| Radio Shack has a quick charger that does AA and AAA NiMH batteries, I think it was about $25.00. The AAA cells I bought were $10.00/pr. Rob Trainer btrainer@home.com rtrainer@csti-md.com Alex Wetmore wrote in message <908291583.842286@phred>... (...) (26 years ago, 13-Oct-98, to lugnet.robotics)
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Message is in Reply To:
| | Charging batteries
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| Our institution (a school) considers to purchase two Mindstorms sets for students to work with. I'm looking for the best way to deal with batteries in such a setting. I have seen some posts mentioning some concerns, but would like to have some more (...) (26 years ago, 13-Oct-98, to lugnet.robotics)
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