View Single Post
  #23   Report Post  
Posted to alt.binaries.schematics.electronic
legg legg is offline
external usenet poster
 
Posts: 436
Default Nickel cadmium batteries & RoHS.

On Sun, 24 Apr 2011 16:48:06 +0100, "Ian Field"
wrote:


"legg" wrote in message
.. .
On Sat, 23 Apr 2011 13:24:54 +0100, "Ian Field"
wrote:


"Martin Riddle" wrote in message
...

"Ian Field" wrote in message
...
Everyone seems to have stopped selling most types of NiCD.

I thought like lead acid batteries they were exempt.


RoHS never covered batteries.

http://en.wikipedia.org/wiki/Battery_Directive

My guess is that the eneloop batteries are far superior to the NICD
types
that its not economical to produce them any more. I'm sure the eneloops
will work as replacements.


There are applications where NiMh won't work.

The NiCds in my shaver gave up and I tried replacing them with NiMh cells,
just running on the bench the charge lasted about 2.5x what the user
manual
said for the original batteries - but under load of actually shaving the
batteries got pretty warm, indicating that not all the rated 2400mAh was
ending up in the motor.

I was getting about 5 shaves per charge with NiMh - new NiCd give
somewhere
between 15 & 20 shaves.


Suggests that they are being operated at a 2 or 3C discharge rate.
NiMhs normally run without exotherm at 1C. How were you bench-testing?



Bench testing was just running with the foil & cutter fitted but not using
it to shave with.

I put a drop of Slick50 on the cutter to reduce wear, the viscosity produces
slightly more resistance than running it dry.


Would be usefull noting the current drain. NiMh usually get hotter in
charging, rather than discharge, in normal service.

There are NiMh varieties constructed specifically for higher discharge
rates - not related to AH capacity. Could be a sales gimmick, but it
would obviously have specific applications, as you have noted.

RL