I took my new HHb Portadisk out recording. The battery indicated 75% at the
start but within 20 minures was down to 10% and the machine stopped. Returning
home I put the supplied DC in and the charge light came on. Within1.5 Hours the
light had gone out and the battery indicator said 99%! I had expected it to
take 12/14 hours. I suppose this was a memory effect from standing for a long
time since packing at the manufacturers.
I have now purchased a special nicad charger and put a new set of batteries on
charge. This took about 12 hours. When I change them over should I
do a couple of discharge, takes 6 hours, and full recharge, perhaps twice with
the original batteries?
I guess you answer will be YES.
I'm a lurker but each days reading of the mail is quite a highlight. Please
keep it up.
Stuart.
[Non-text portions of this message have been removed]
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>From Tue Mar 8 18:22:57 2005
Message: 10
Date: Thu, 07 Nov 2002 21:56:23 -0500
From: Walter Knapp <>
Subject: Re: Nicad charging.
Stuart Fairbairn wrote:
> I took my new HHb Portadisk out recording. The battery indicated 75% at the
> start but within 20 minures was down to 10% and the machine stopped.
> Returning home I put the supplied DC in and the charge light came on.
> Within1.5 Hours the light had gone out and the battery indicator said 99%! I
> had expected it to take 12/14 hours. I suppose this was a memory effect from
> standing for a long time since packing at the manufacturers.
Nimh batteries don't have the same sort of memory effect problem as
Nicads did. It's probably not memory.
That is pretty short time. What brand and size batteries did yours come
with? Mine came with Fujitsu's, NIMH 1550 mAh, white with orange top. I
replaced those with higher capacity batteries almost immediately. But I
continued to use the Fujitsu's elsewhere. One set of four fairly quickly
got to where it would not hold a lot of charge, now recently the other
four are beginning to do the same thing. They vary from charge to charge
as how much they will take, sometimes practically nothing. I was not
impressed with those batteries, the only NIMH I've had problems with.
All other NIMH I have still are taking a full charge, and some are even
older.
This year I used two sets of GP 1800 mAh batteries in the Portadisc,
mostly charging them in it. Those take about 6-7 hours to charge in the
Portadisc, but I almost never let it get below 90%, usually recharging
before it's even dropped off 99%. The charge rate of the Portadisc is
somewhere between a slow charger and a fast charger.
Today next year's batteries for it arrived, since I work at night I have
a whole sack full of rechargables organized in matched sets. The low end
is my remaining Nicads, and as those die I replace with NIMH, always
buying whatever is the latest version and putting them in the Portadisc
and moving the rest down the usage chain. I've been going through my
batteries and a number of Nicads were not fit this time. The GP folks
have put out the 2000 series NIMH AA's. Kind of a misnomer as these are
"only" 1900 mAh. So I got two sets of those. My previous set was also
GP's. The set before that Kodak. Kodak lost the last two times because
they are one step behind in capacity. Current top Kodak AA's are 1850 mAh.
I have 8 of the GP 2000's on the reconditioning/discharge cycle on a
couple of my Maha C204F chargers. They arrived just under fully charged.
I discharge NIMH this way periodically, and do it to new batteries. That
insures a uniform charge in the set. (Nicads I do it every charge cycle)
I don't expect the set will be done until tomorrow. Discharge will take
longer than charging. But, it's all automatic in the Maha.
BTW, the first thing I do with new batteries is take a industrial grade
sharpie and mark the month and year on them.
> I have now purchased a special nicad charger and put a new set of batteries
> on charge. This took about 12 hours. When I change them over should I
> do a couple of discharge, takes 6 hours, and full recharge, perhaps twice
> with the original batteries?
>
> I guess you answer will be YES.
For NIMH that are misbehaving that bad I'd do two discharges. But I
expect you will want to relegate them to less demanding uses and go with
the newer high cap NIMH. Judging from the Fujitsu's I have. They now get
to power headlamps, but only if I'm carrying a backup set of another
brand. They are very close to going to recycling. After only two years.
The Nicads that went this year were all more than 5 years old.
As for new NIMH, a single round of discharge is plenty, maybe overkill.
You are just insuring a even charge through the set.
You should be using a charger rated for the charge profile of NIMH,
which is different than Nicad. It's ok at slow charge, but fast charge
they differ. Don't even bother with Nicads. If you have some, use them,
but NIMH beat them every way.
For maximum life out of the NIMH, only go to about 80% on the Portadisc.
At that they are near the minimum voltage you are supposed to take them
to before charging. Running them all the way down each time will shorten
their life a little. What you need to do is use the same batteries in
both holders, and learn just about how long they will give you, the
battery indicators on all these things have problems as the batteries
hold at full voltage until almost the end, then drop like a stone. (and
with each new generation of them they hold voltage even longer) That
leaves very little to be detected to indicate charge level. My Sound
Devices MP2 is even worse, from the time the battery light goes red you
have less than a minute until shutdown. Only way is to keep some sort of
idea how long they have run. It is not damaging to recharge NIMH without
running them all the way down. As I said, I do use the charger to
discharge them to level them out. But the Portadisc ones are mostly
charged internally.
In my usage I've got lots of charged batteries around, so am pretty
casual about keeping track. I do exchange which set is in the Portadisc
periodically to keep them near the same usage level.
In spite of all that I'm not going to go alkaline just to get the
battery indicator to mean more. NIMH last a lot longer per charge, and
cost a whole lot less overall.
Walt
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