Battery connections on laptop. - test-drb@ccmp.vtda.org

16 Jan 2004

  Some battery packs use separate leads for charging and to supply power.
Also most packs (other than NiCad) have a thermistor to control the charge
rate. Many also have a thermal circuit breaker. All of these require
additional contacts. The Li-Ions in particular often have the circuit
breaker since they are prone to exploding violently if they are improperly
charged or used. In addition, some of the contacts may be paralleled with
other contacts to increase the current carrying capability. You'll have to
break open the pack to see exactly what they're all used for. Li-Ion, Ni-MH
and most of the newer batteries have very exactly charging and use
requirements. I STRONGLY recommend not switching battery types.  Save
yourself a lot of aggravation and replace the cells with the same type of
cells. Spend your money on buying GOOD cells and not the Mexican or
Chinesse made junk.  I've had extremely good luck with the JAPANESE (NOT
Mexican!!) made Sanyo NiCads but I can't say about the other type cells.

   Joe

At 03:10 PM 1/15/04 +0100, you wrote:
...
 I just bought a somewhat older laptop, though I hope
you will all forgive 
me if it is slightly younger than the borderline for the interests of this 
group  (I am not sure on which side of the line it lies.)

It is a Toshiba 4010CDT, which uses a Li-Ion battery, the subject of this 
message.   I am amazed at the number of contacts between the battery and 
the computer  (about 10) and wish to know their function.  On the Internet 
I find nothing.    On account of the short life-time of such batteries I 
want to install NiMH.   I accept that I would have to use a separate, 
external charger, even removing the reserve battery fro the charging 
process, as the price of being able to travel with a back-up battery which 
would not die after two years of having it around.

The problem is all those connections;  I have no idea what they do and only 
a couple of them are needed for transfer of power to the computer.  At 
least part of the rest must be communicating  data about the state of the 
battery, either for the sake of charging or for warning of the soon-to-come 
shut-down for lack of enough power to continue.   I would have to lie to 
the computer in such a way it thinks it is monitoring a Li-Ion battery, but 
to do it I need to know what the lies must say.   Does anybody have a clue 
what the functions of these connections are?

Keeping my fingers crossed,

Bob 