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G4YUU > INFO 11.08.02 21:44l 68 Lines 2749 Bytes #999 (0) @ WW
BID : 197586G4YUU
Read: DB0FHN GUEST
Subj: Re: Rejuvenating NiMH cells??
Path: DB0FHN<DB0ZWI<DB0HDF<DB0ERF<DB0MRW<OK0PKL<OK0PHL<OK0PCC<OM0PBC<HA5OB<
HA3PG<GB7FCR<GB7BOB<GB7OAR<GB7SAM<GB7MAX
Sent: 020811/0905Z @:GB7MAX.#28.GBR.EU #:12165 [Bloxwich] $:197586G4YUU
From: G4YUU@GB7MAX.#28.GBR.EU
To : INFO@WW
[ 11/08/2002 10:03z #:7586 @:G4YUU QRA:IO92CN ] .
" Digital TV/Radio, Progression from Invention "
GM7HUD wrote with great skill:-
> I've got 4 old NiMH cells left. I was wondering if they could be
> rejuvenated in anyway. Over the years I've had reasonable success
> rejuvenating NiCd cells which have lost their ability to hold a
> charge. I've always used the big current pulse method which seems
> remarkably effective, I guess I must have had over 75% success
> rate. But I've never seen anything mentioned about NiMH cells.
>
> Before I try any NiCd measures on them I was wondering if anybody
> had tried anything and what success they'd had?
Hi There
This week I obtained a Motorola m3788 mobile phone and the internal
NiMH battery pack was flat.
First I soldered two thin pieces of tin on to the battery terminals
and then used my "Whisker Blowing" unit with my voltmeter also
connected to the battery tin strips. Did this whisker blowing for
about an hour and saw just a slight charge in the battery pack.
Next I connected the battery charger PSU direct to the battery pack
outside the phone. The voltage shot up to 5.8 volts. Placed the
battery back in the phone with the tin strips and voltmeter still
attached. The phone fired up immediately and went flat straight away
so deduced that must be a "current" configuration inside the phone
when charging through the phone as obviously the volts were there but
no amps/current..
Charged the battery in the normal way inside the phone still with the
tin strips and voltmeter attached. For the next few hours I monitored
the voltage rise in the battery and then left it on overnight as if
one was giving the initial charge of 16 hours as usually advised.
Next morning yesterday, Saturday, looked at the phone and found
"Charging Complete" and the voltmeter read 5.8 volts as it should be.
The phone is now working as if I had inserted a new battery which
shows that NiMH batteries can be reclaimed.
Just checking now that the charge will last and have been switching
the phone on and off many times and just one of the three bars of the
battery has been used having checked before I switched on my computer
for Packet this morning.
I had already removed the tin strips and placed the rear plastic
cover back on the phone.
Next job is to reclaim some Nicad batteries that I found in an old
domestic Dustbuster which are the same size as in a battery pack I
have for a cordless drill. Some of the Nicads are finished so will
make up a new battery pack saving a cost of 37:00 gbp which is dearer
than a reasonable drill costs.
Cheers
73, John, G4YUU @ GB7MAX
09:54 on 11 Aug 2002
WinPack V6.52 (R)
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