RE: [Thinkpad] Refill/Recell IBM Battery

Dear Steve,

This is a very good information for me, many thanks! The website you =
told me
in your email is very informative.

About how to test which cell is working, I found that I can test it =
using a
multitester. I repack them, test them and found some of them have no
reaction (the multitester arrow still in number "0") and some of them =
give a
reaction (the multi tester arrow is go to higher number/the arrow in
multitester is moving).
Can I test them in that way?

Please don't get me wrong, I am not going to provide a professional =
support
for my customer regarding to batteries. I sell user laptops and want to
equip the laptops with working batteries (with normal performance, I =
don=92t
need to equipt the laptops with a best performance like brandnew =
batteries
do).
Refill/recell those batteries to 3rd party cost me a lot, that is why I =
want
to recell them with "normal" performance.

Any suggestion are very welcome :)

Kopaja.

> -----Original Message-----
> From: Steve Carter [mailto:scarter@vcnet.com]=20
> Sent: Monday, January 03, 2005 8:11 AM
> To: Supir Kopaja
> Cc: thinkpad@stderr.org
> Subject: Re: [Thinkpad] Refill/Recell IBM Battery
>=20
>=20
> The best battery site I've seen recently is at:
>=20
> www.buchmann.ca
>=20
> As a good starting place, read and learn everything they have=20
> to offer.=20
>=20
>=20
> 1. All the cells in a used Li-Ion battery are the same age. =20
> By the time one cell has failed, those that haven't yet=20
> failed will fail sooner, rather than later. The Li-Ion=20
> chemistry has an aging mechanism and even without use, the=20
> cells will all fail=20
> within a few years. Replace them all at the same time. =20
> =20
> 2. Different manufacturers' cells have different=20
> characteristics, despite the same specifications. The=20
> electronics in the battery pack senses when one cell (in the=20
> series string) charges faster than another and terminates the=20
> overall battery charge, so that the aged cell does not become=20
> overcharged and thus become a fire/explosion hazard.=20
>=20
> Ideally, one would use matched cells to make a battery. =20
> Normally, this is not practical. But in any case, all cells=20
> _WILL_ age differently.=20
> As the cells age differently, they will become unmatched. =20
> =20
> 3. It is not desirable to over-discharge Li-Ion cells, as=20
> then may not re-charge properly. The discharge cut-off=20
> voltage is often given as 3.0 volts. This is the parameter=20
> that any sensing circuit would use. =20
> Therefore larger-capacity cells _SHOULD_ give the longer=20
> runtime battery that you expect, IF all the cells are the=20
> same. Larger-capacity battery packs are already available for=20
> many TP's.=20
>=20
> My TP 600 uses three series pairs of cells, six total, for=20
> 3.6Vx3=3D10.8Volts.
> The connection between pairs of cells is monitored for=20
> voltage imbalance, in order to detect unequal/over charging=20
> and discharging.=20
>=20
> End-of-discharge is determined when the weakest (any) cell=20
> drops below the cutoff voltage (~3.0V) and charging is=20
> stopped when the weakest (any) cell rises above the maximum=20
> peak charging voltage allowed, (~4.1V).
> =20
> Personal comment:=20
> I have not actually autopsied or investigated TP battery=20
> packs beyond the above, but these principles are almost=20
> universally applied to Li-Ion batteries with cells in series. =20
>=20
> In high-reliability applications, elaborate and costly=20
> cell-bypass schemes are sometimes created to prevent=20
> overcharging of weak cells and thus fully charge the=20
> remaining cells in a series battery string (of up to 8 Li-Ion=20
> cells in my experience). =20
> =20
> There is also much discussion of this subject in the=20
> archives, which you should read, understanding that there may=20
> be some inaccuracies and speculation.=20
> Different battery packs should be expected to behave=20
> differently. IBM has had several different model numbers for=20
> the battery for my TP 600, and even one recall, IIRC. =20
>=20
> Best of luck! =20
> =20
> +++++++++++++++++++++++++++++++++
> On Sun, 02Jan05, "Supir Kopaja" <kopaja@gmail.com> wrote, in part:
> > ...
> >First of all, I am sorry for my poor english. I plan to do a battery=20
> >refill/recell business. I understand that most of the IBM batteries=20
> >consist of 6 or 8 pcs Li-Ion batteries cells [and] that the=20
> >specification are 3.6V or 3.7V and 1800mAH (min).
> >
> >My question are:
> >
> >1. Should we replace all the cells since most of the time not all=20
> >cells defected?
> >
> >2. If we allowed combine brand new cells with current cells, can we=20
> >combine them that have different brand but same spec?
> > (for example: current cells are panasonic, we combine with =20
> brand-new=20
> >cells brand sony, but both panasonic and sony same the same=20
> >specification)
> >
> >3. Since batteries pack consist of 6 or 8pcs cells, in what =20
> way we can=20
> >verify which cells are functioning and which are not?
> > Is there available charger or tester to test these Li-Ion=20
> battery cells?
> >
> >4. Is that true that the battery SMBus (System Management Bus, the =20
> >batteries "mainboard") control how long a battery could operate?
> > I mean, the batteries can have a different performance =20
> even I replace=20
> >all of the cells?
> >
> >I hope this is the right mailing-list to ask these=20
> questions, if not,=20
> >may anybody suggest me the right mailing-list to do this?
> >
> >Many thanks.
> >Kopaja.
> >------------------------------
> =20
>=20
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> =20
>=20

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Received on Tue Jan 4 11:37:22 2005