At 8:32 PM -0400 2/10/01, Michael Dolberry wrote:
>From: Michael Dolberry <[EMAIL PROTECTED]>
>Subject: That 170 battery rollercoaster
>
>Hi Folks,
>
>I am in the process of reconditionong the battery on
>my wife's PB 170.
>
>I have deep charged and discharged it several times,
>as recommended.
>
>The last two times the discharge curve has almost been
>identical. It runs down to about 25% after only 6
>minutes and then ramps back up to about 35-40% for
>about 5 minutes more, until finally discharging
>completely after about 35 minutes.
>
>While this explains why the battery goes to sleep
>after about 5 minutes, I wonder if this is a symptom
>of a bad battery or something.
>
>Has anyone else encountered such a thing?
>
>Mike Dolberry
yep, I've had similar results from two batteries that i've tried to
recondition for my 170. I was quite surprised by the spike at 5 mins
or so, but I decided it must be a feature of the chemistry of these
batteries when they're on the way out. (unless it's the rate of
discharge, but this is on Battery Amnesia, which I think gives a
constant rate of discharge). I gave up and pulled the cells from one.
They all held an initial charge, and I haven't had a chance to check
them out past there. But yes, my guess is that your battery is
probably u/s.
I'm sorry to say I don't like your chances with the external charger,
either. I have one of these and it didn't really help the two weak
batteries, not for want of trying. My guess is that Battery Amnesia
achieves a better discharge in any case.
I'm currently working on putting together a pack that will go through
the old battery shell to the regular battery terminals (so that the
machine reads it as a battery rather than ac adapter from the dc
input at the back). I'm wanting to do this without soldering the
cells, so I can put them to other uses and increase my recharging
options. Once again, I haven't had a lot of time to put into this,
but it seems that the connections between the cells and from the
external battery to the PB terminals need to allow for a high drain
(and you need to be very careful not to short the terminals).
One funny thing: using one of the bad batteries I've described, I've
been able to get an external battery pack wired through in parallel
to extend it's life to about an hour but after I removed the dodgy
cells from the original battery, I couldn't get enough power out of
the external pack alone to stop the PB from going down.. My guess is
that the wiring on the external pack isn't heavy enough to provide
the necessary current, but it will trickle in to augment the old
cells.
Any thoughts and experiences with other variants to the old NICd
battery rollercoaster? I noticed someone recently remarked about
replacing NiCd cells with NiMH. I've been working on the assumption
that the 170 charger won't do a good job with NiMH cells, and would
be likely to undercharge or cook them. Does anybody have any
experience with this?
best wishes, and can I add to other peoples' comments, that although
I'm only a (very) occasional contributor here, I really enjoy the
spirit and tone of the discussion.
--
John Pitt
Community Management and Development Program
Centre for Aboriginal Studies
Curtin University
GPO Box U1987 Perth, Western Australia 6845
ph: (08) 9266 3379
fax: (08) 9266 2892 / 9266 2888
home: 7 Melville Beach Rd Applecross WA 6153
(08) 9364 8808
--
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