In article ,
Jeff Liebermann wrote:
True for the Duracell, which recommends 205ma for 15 hrs to recharge
printed on the cell. The Energizer Recharge battery doesn't specify a
charge current:
http://data.energizer.com/PDFs/nh15-2000.pdf
However, the recommended battery charger is a quick charger:
http://data.energizer.com/PDFs/ch15mn2.pdf
with a 15 minute charge time.
I've been testing batteries since about 2005 while working on a
product that I won't discuss. However, I will point out that many
NiCd batteries can be quick charged at ridiculously high rates, as
long as certain (unspecified) conditions are met. If you don't mind,
I'll leave this unsubstantiated.
Incidentally, the Sanyo ENELOOP battery data sheet recommends fast
charging at 2A for 1.1 hrs:
http://www.eneloop.info/fileadmin/EDITORS/ENELOOP/DATA_SHEETS/HR-3UTGA_data_sheet.pdf
Interesting. Another page in the Sanyo FAQ section (at
http://us.sanyo.com/eneloop/FAQs) says:
Though it is possible to charge an eneloop battery in a "Quick
Charger", it is not recommended. We recommend charging eneloop
batteries in a NiMh charger that is 2 hours or more. Charging eneloop
batteries in a "Quick Charger" can reduce the overall life of the
battery.
I've read statements to the effect that one reason you would want to
use moderately-fast charging rates (e.g. 1C) rather than the low rates
traditional for most NiCd cells (e.g. 0.1C), is that the NiMH cells
will heat up more abruptly when they reach full charge, and the
charging power starts turning into heat rather than electrochemical
potential. The abrupt rise in cell temperature is easier to detect
reliably (via a temperature sensor and/or due to the zero-delta-V
effect) than if you were charging more slowly... and thus a more
reliable "full charge, stop now!" shutoff circuit can be designed, and
avoid overcharging (which I understand NiMH cells don't tolerate at
all well).
Incidentally, all of the marine radios I helped design were required
to function down to 10.0VDC applied power. They couldn't reach rated
TX power at 70% of rated voltage, but still had to belch at least a
few watts of RF and remain functional.
A good decision! It bothers me that a lot of HF and VHF radios "poop
out" at much below 12 volts.
I'm rather mystified by the results. Although the improvement in
capacity after 3 charge-discharge cycles is minor (10-15%), it still
seems for real. My previous tests didn't show such an increase in
capacity. Instead, it showed a deterioration in capacity. However, I
was testing for something quite different, and was working with a mix
of old and new cells.
For what it's worth, the Sanyo FAQ page cited above does make
reference to the break-in effect:
Should I store my batteries charged or uncharged?
If stored with charge, it is possible that when you return to use
the battery there may still be some charge left in the battery,
therefore it will enable you to use it right then and there. Also,
by keeping some charge in the battery, it will require you to
"cycle" the battery fewer times until it reaches its peak charge.
If you store them with no charge, you will have to "cycle" the
battery multiple times until it reaches its peak charge.
--
Dave Platt AE6EO
Friends of Jade Warrior home page:
http://www.radagast.org/jade-warrior
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