Repair of a portable computer battery pack

Hi, I'm writing from a Gericom Webshox portable computer of 2001, now the battery pack ( UN241S1 Rechargeable Li-Ion Battery Ratings:

14,4Vdc 3600mAh ) is broken son I decide to change the accumulators, I choose 8 NiMH 3,6Ah 1,2V Accumulator.

After the substitution it still doesn't work, the charge seems to be ok, also is I do not understand why is used a 14 Volt supply to charge battery pack to about 5,8V


  • +

- - ------------------white

  • +

- - ------------------yellow

  • +

- - ------------------green

  • +

- - ------------------black

The discharge phase is not ok, the 5,8v coming from the accumulators seems to be blocked in one of the two printed circuits comprised in the battery pack, so my questions:

1) What is the job of these two circuits?

2) It is possible to connect directly the accumulators to the output bypassing these circuits?

3) What the white, yellow and green wires are used for??

4) where I can found a scheme of a typical battery pack ??

5) why the supply is 14v to charge a 5,8v battery pack ??

Hoping in your help

many thanks ...

Antonio D'Ottavio

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seems to be



pack, so

the output

You will become in time very smart by asking such questions...even if they are off on the wrong track...most questions are in the discovery phase.

problem is that the chemical components in the battery after 4 years now, are exhausted... and so you are getting all of these symptoms..its probably not a bad circuit.

I suggest you do some research on how a battery of that type works, and ages .... and dies..

Phil Scott

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Phil Scott

I am not sure I understand what you are doing. The UN241S1 produces 14.3 volts. The 5.8 volts you mention for the substitute battery pack is not good.

If you substitute NiMh cells, you need to use

12 cells, in series, to get 14.4 volts, nominal.

You also need a different charger - the cells need to be charged to a charge termination voltage of ~ 1.4 volts per cell, or 16.8 volts for the pack. That suggests a possible charging voltage of about 20 volts with current limiting, depending on the charge algorithm.

You might be better off using a 12 volt gel cell.


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