Re: [NTLK] 2000 mAh batteries

From: marco.mailand_at_ch.abb.com
Date: Thu Oct 17 2002 - 11:46:59 EDT


>I find 1800 mAh at wal mart, yeah I know but hey they have ray o vacs
>that are that size so I bought a set of four and they work great...
Ray-o-vacs are carbon-zinc cells whith reinforced electrodes. They are
intended to be charged a few times unlike an accu cell which allows usually
hundreths of cycles. Standard carbon-zinc cells can be recharged too,
provided than one uses a combined AC-DC charging voltage, e.g. 70% charging
and 30% discharging ratio. And that's why Ray-o-vacs come with their
special charger. The Newton charges with pure DC only and will thus reduce
the lifetime of the Ray-o-vacs, because the case metal will be worn
unevenly. I made such tests about 24 years ago as I was in junior high
school and found that the capacity of carbon-zinc cells is increased during
the first 4 recharging cycles by a factor of about 25% (with 30/70% AC/DC
mix). After cycle 5 to 10 the capacity decreases until the cell gets a
leak.
And I found that the build-up of leaks is faster with DC charging only
(like in the Newton) than with AC/DC mix. It maybe that the Ray-o-vac use a
combined stainless-steel/zinc vessel as minus electrode and thus leaks are
not possible but I wouldn't rely on that: An accu is certainly cheaper and
more secure.

Marco

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