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Science Forum Index » Electronics - Repair Forum » Low Voltage Cutoff of a handheld...
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| Antoni Mont... |
Posted: Fri Jul 11, 2008 5:55 pm |
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Guest
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Hi all,
My Palm (Tungtent E2) seams bad ill. After some test I concluded that
the battery (Li-ion 3.7V 1020 mAh) is OK. It charges at 4.05V and
keeps voltage agains a load of 36 ohm. The trouble is that the Low
Voltage Cutoff circuit, that ought to act at about 3V, cuts in fact
at 3.95V. So the span life of a charge cycle is very shorts: less
than one hour. All circuitry is micro-micro electronics, so I have
very little expectations about the possibility of doing anything on
it ;-( Nevertheless, before throw it away I dare to ask to the group:
any similar experience?, any ideas about where to find information of
that kind of circuitry?
Thanks for your help,
Toni |
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| mike... |
Posted: Wed Jul 23, 2008 11:07 pm |
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Guest
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Antoni Mont wrote:
Quote: Hi all,
My Palm (Tungtent E2) seams bad ill. After some test I concluded that
the battery (Li-ion 3.7V 1020 mAh) is OK. It charges at 4.05V and
keeps voltage agains a load of 36 ohm. The trouble is that the Low
Voltage Cutoff circuit, that ought to act at about 3V, cuts in fact
at 3.95V. So the span life of a charge cycle is very shorts: less
than one hour. All circuitry is micro-micro electronics, so I have
very little expectations about the possibility of doing anything on
it ;-( Nevertheless, before throw it away I dare to ask to the group:
any similar experience?, any ideas about where to find information of
that kind of circuitry?
Thanks for your help,
Toni
Could you be a little more descriptive about how you made the
measurements and how they took into account high peak currents and
increasing battery resistance?
Did you put a scope on the battery and verify that the valley
voltage doesn't dip?
Did this happen suddenly or gradually?
My money is on the battery...
mike |
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