> -----Original Message-----
> From: Duo/2400 List
> [mailto:[EMAIL PROTECTED]]On Behalf
> Of John Ruschmeyer
> Sent: Monday, July 15, 2002 2:47 PM
> To: Duo/2400 List
> Subject: [Duo2400] Re: Any way to rescurricate dead Type 3
> batteries?
>
>
>
> > Message-ID: <000901c22b96$3834fa40$e7c0fea9@nowhere>
> > From: "Impmon" <[EMAIL PROTECTED]>
> > Subject: [Duo2400] Any way to rescurricate dead Type 3 batteries?
> > Date: Sun, 14 Jul 2002 20:25:52 -0400
> >
> > I have 4 Type 3 batteries that are dead (all causes the
> Duo to shut down if
> > inserted after power up, and gives red light on external
> chargers) and I'd
> > like to know if there's any last resort tricks to revive
> these batteries? I
> > only have one good Duo battery left (still holds 2-3
> hours on full charge)
> > and I'm not going to shell out over $50 on eBay for a
> mystery battery. ;)
>
> I have one Type 3 which has also failed this way and am
> really wondering
> what causes it.
>
> I happened to check the resistance across the + and - terminals and
> noticed a very large resistance (1.2Mohm) as compared with a good
> battery which shows almost no resistance.
>
> I'm wondering... is this a failure of one or more cells or
> of one of the
> safeguards in the battery (thermistor, self-resetting
> circuit breaker,
> etc.). Anybody know of a way to check without opening the battery?
>
> Thanks...
> <<<John>>>
This is normally a sign that 1 or more cells have gone short-circuit,
measuring the resistance with a standard multi-meter is not going to
give any meaningful reading due to residual charge in the cells, try
using a bench PSU set to 14V, a good battery should draw a heavy
current for a short while (assuming it is flat) which will rapidly
drop to ~200ma, if one or more cells are shorted then it will draw 2A
or more and not drop significantly, (I suggest limiting the current to
500ma and charging at this rate for 10-15 minutes then seeing what the
current draw is when you up the limit, otherwise the battery may
overheat with nasty results).
If this is the case then all you can do is open the case and identify
the faulty cells (use a voltmeter with a 10ohm load resistor across
it's terminals) the faulty cell(s) will read below 1V, you can
sometimes resuscitate these by 'zapping' them with a large capacitor
(10,000uf) across a 20-35V psu, just apply a brief touch, you get a
good spark as it discharges, repeat 10-20 times then charge the
battery, if you are lucky it will work again, however in my experience
the cells quickly fail again and you will end up having to replace
them in the end.
NB always replace ALL the cells at the same time, do not be tempted to
mix old and new cells as their capacities will be different and it
will quickly fail again.
Ben.
NB if the battery pack starts to get HOT then remove power at once!!!!
----------
Duo/2400 List, The friendliest place on the Net!
A listserv for users and fans of Mac subportables.
FAQ at <http://www.themacintoshguy.com/lists/DuoListFAQ.shtml>
Be sure to visit Mac2400! <http://www.sineware.com/mac2400>
To unsubscribe, E-mail to: <[EMAIL PROTECTED]>
To switch to the DIGEST mode, E-mail to <[EMAIL PROTECTED]>
Need help from a real person? Try. <[EMAIL PROTECTED]>
----------
Dr. Bott | 10/100 Ethernet for your 2400 is finally here!
MPC-100 | <http://www.drbott.com/prod/mpc100.html>
RoadTools $30 PodiumPad available at Apple retail stores, $20 Traveler
CoolPad at Staples. Both in white for iBooks at <http://roadtools.com>
Midwest Mac Parts ][ <http://www.midwestmac.com>
After-market parts for Macs. ][ 888-356-1104 ][
MacResQ Specials: LaCie SCSI CDR From $99! PowerBook 3400/200 Only $879!
Norton AntiVirus 6 Only $19! We Stock PARTS! <http://www.macresq.com>
