Re: [NTLK] MP 2100 Battery reconditioning

From: Jeff Smith (jeff.smith_at_allenmicro.com)
Date: Tue May 14 2002 - 16:56:08 EDT


My only comment is great thinking...I think this will give someone somewhere
one last hope for saving a bad battery perhaps ;-) I'm not sure what Lava
is, but can I assume it's an app that monitors (among other things) battery
temp and usage?

----- Original Message -----
From: "Thomas Hofts" <thofts_at_mac.com>
To: "Newton Talk Messageboard" <newtontalk_at_newtontalk.net>
Sent: Tuesday, May 14, 2002 4:14 PM
Subject: [NTLK] MP 2100 Battery reconditioning

>
> I know this subject has been discussed to death.
>
> My 2100 with the rechargeable NiMh battery I got from Philly Discounter's
> suffers from the "10 min. charge time - 4 hour continuous use life (using
> back light)" problem. I tried the "let it run out completely and
recharge"
> solution a couple of times, but still had the 10 min. charge time.
> Monitoring the battery via Lava during the charge I saw a rapid rise in
> battery temperature which coincided with the percentage of charge in the
> battery. So I decided to conduct an experiment theorizing the rise in
> temperature was preventing erroneously showing the battery receiving a
full
> charge.
>
> 1. I placed the battery in my freezer and cooled it to 32 F, wiped it to
> remove any condensation, then placed it back in my 2100 which was powered
up
> with the AC adapter. I then immediately unplugged the AC and to my
surprise
> the "discharged" battery continued to power the 2100 with back light on
for
> 8 minutes, finally dying when it dipped below 10%.
>
> 2. I then rebooted the Newton with the AC. The monitor showed the
battery
> taking a "trickle charge" for 9 min. until the battery temperature reached
> 41 F. Then it went into fast charge mode. The battery temperature
gradually
> rose until it reached the ambient temperature 37 minutes later (82%
> charged).
>
> 3. I placed a small icepack wrapped in cloth at the very end of the
Newton
> (not on top of it) to help keep the battery temperature cool. This kept
the
> battery 3 degrees cooler than the ambient temperature. The battery
continued
> to fast charge and reached 100% and trickle charge 16 minutes later.
>
> Total charge time was 53 minutes. I then allowed the trickle charge to
> continue for another hour.
>
> Disconnecting the AC, I left the 2100 on, with the back light on, and it
ran
> for 11 hours 22 min. before shutting down.
>
> I then recharged without cooling the battery and the total charge time to
> 100% was 48 min.
>
> Seemed to work, at least for the short term.
>
> Any comments?? (Outside of the fact that I have too much time on my
hands!)
>
> --
> Tom Hofts
>
>
>
> --
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>

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