On Sat, 27 Aug 2005 08:13:30 +0900, H. Dziardziel
wrote:

On Thu, 25 Aug 2005 18:55:43 -0400, Darmok
wrote:



Charging in only 20 minutes is a 3C charge rate ie, three times
the cell mAh capacity. Shaver NiCads would be in the 500m-1000Ah
range. NiMh 2000-2600mAh AAs can handle that 1500-2000mA charge
rate but must not go over full charge or will be destroyed.

The question is: is that a timed 20 minutes or a "smart" 20
minutes? If timed and one starts with fully discharged cells
then all is well. NiMh have no memory effect so can be charged
and dicharged from-to any level But, if a smart charger is used,
it may not properly detect the NiMh charge state and keep charging
past fully charged.

For say, 1500mAh cells, that would take about one hour however so
manul timing would suffice. Monitoring the cell temperature is a
good idea. Some heating while charging is normal for NiMh but
after full charge is reached it quickly ruins the cells.


Well, I did as someone suggested, and "Googled" for "Norelco battery
replacements". I found a place that carries replacements for almost
all versions of the Norelco shavers. When I looked up my model number
(4845XL) it showed them as a pair of AA NiMH batteries! When I looked
at the actual cells in the shaver, they were a pair of 600mah Ni-Cds.
So, since I have a lot of NiMH cells around (for digital cameras and
hobby use), I decided to solder in a couple of them and see what
happens.

The first thing I noticed was that, for the first time in years, the
RED charge LED came on (for a few minutes) as well as the GREEN LED.
It then proceeded to charge for about 20 minutes, then the GREEN LED
began flashing, and I knew charging had stopped. The case of the
shaver felt warm, but not as warm as when there were Ni-Cds in there.
I've been using it now for a couple days, and it has plenty of zip,
and sounds real good (by the pitch of the motor). BTW, I assume that
there is some kind of "smart charging" going on, as if I were to plug
it in after only a couple days, it would shut off (green LED blinking)
after only a few minutes. Maybe its voltage based?

I guess I'll know how well, this works after some time has expired,
but for now, it appears to be working well. BTW, I have 2 Norelco
shavers, and this is the older of the 2. I use one until it runs
down, then grab the other one, and put the exhausted one on charge.

Thanks again ..

Bill, KB8EB