Date: Thu, 10 Feb 2005 09:39:00 -0600
From: McClanahan, Eddie [EMAIL PROTECTED]
Subject: RE: [LIB] Libretto Batteries - Rebuilding
Here is a little more information about rebuilding the battery pack.
I examined the circuit and got information about its function from
several vendors of batteries -
The circuit is there to optimize the power pack (battery) output during
it expected life time range. The circuit monitors the total charge
cycles, duration, discharge rate, and temperature of the batteries plus
calculates the expected cycle usage time. The calculation parameters are
given by the manufacture of the batteries. The cycle usage time is the
data is supplied to the computer.
In early battery packs when the circuit calculated the batteries were
exceeding the optimized cycle usage and the circuit reported a very low
usage time plus would automatically shut down the computer even though
you could measure the battery output with load and see the batteries
were good. To reset the battery required disconnecting the circuit,
waiting 5 minutes and reconnecting the circuit and it indicate 100% user
time. Note there is one or two cell directly connected to the monitoring
circuit.
Now, if you check closely, the battery monitoring circuit has a crystal
device which mean a clock and a memory chip which mean the circuit does
not reset when disconnected.
Additionally if the battery manufacture and the manufacture of the
computer are friends both have the possibility to communicate the
cycle and charge frequencies of the battery, so just replacing the
dead cells may not bring the bat pack back to life for the computer.
Ever notice the ID of the battery pack indicated in the control panel?
Reg-
McClanahan
-Original Message-
From: Matt Hanson [mailto:[EMAIL PROTECTED]
Sent: Thursday, February 10, 2005 1:21 AM
To: Libretto
Subject: Re: [LIB] Libretto Batteries - Rebuilding
Date: Wed, 9 Feb 2005 23:20:00 -0800 (PST)
From: Matt Hanson [EMAIL PROTECTED]
Subject: Re: [LIB] Libretto Batteries - Rebuilding
--- John Liu [EMAIL PROTECTED] wrote:
I am thinking about buying lithium cells of the same dimension and
capacity (ideally even the same make and model), unsoldering the bad
cells, and rebuilding the pack. Has anyone done this? Are there any
special tricks?
A few people have had success rebuilding their battery packs. You do
have
to be very careful to get everything reassembled exactly without
damaging
the ciruit board, mis-wiring things, or making any other errors. LiIon
batteries not installed correctly can explode and make an average day
turn
into a nightmware. It'd be smart to plug the rebuilt battery pack into
a
Libby battery charger, put the charger on one side or a wall, and run
the
cord around to the other side before plugging it in and testing to see
if
the rebuild went well.
With that warning though, you can get replacement cells from Sabah
Oceanic:
http://sabahoceanic.com
You'd want the Panasonic CGR17670HG cells. Plug that part number into
Sabah's search engine and you'll find them at $7.40USD each. Nice thing
is
that they're 1500mah instead of the original 1200mah cells, so they're
power the Libbys a bit longer. The original cells were 17mm by 67mm,
and
those CGR17670HGs are a hair shorter, so they'll fit fine.
There are also 18mm wide Panasonic cells that a couple people squeezed
in
by hacking off the sides of the battery pack shell. They are higher
capacity, but the finished rebuild looks like hell. Not a huge problem
those I guess, as I think only the top and back sides get hacked off.
Once
in the Libby, I don't think it looks normal.
Sabah will also weld soldering tabs onto to the cells for free. They do
that overseas, so I guess they aren't subject to suits that could
develop
if they were providing the cells from here in the USA. In fact they say
they'll weld cells to any spec they're provided with. I was wondering
if I
could send them the dismantled battery pack, and have them attach the
whole
circuit board onto the new cells for me.
You could also get one of the extended battery packs for the 50/70s off
EBay that go for a lost less than the ones for the 100/110s, and then
just
swap the contents. That worked fine for me. I had one of those for my
70CT. Dropping it's guts in the 110 pack works fine, and has for
everyone
I've heard from that's done this. I just never bothered to glue the 2
halves of the pack together, as I'd like to go the Sabah route myself at
some point. And the pack stays together quite nicely after it's plugged
into the Libby.
I see that I can buy a new pack for around $100, but I'm a bit
skeptical - not sure how I avoid getting a used pack for my $100. I
also found some places that commercially rebuild battery packs. What
do you think about these alternatives?
As I pointed out, everyone I've written has had success just buying a
50/70
pack on EBay, and swapping. Someone complained that you never know what
thecondition
