HP Pavilion battery charging circuit defective

Archived from groups: comp.sys.laptops (More info?)

I have an HP Pavilion ZT1135 notebook computer running Windows XP Home
Edition. The unit is about 30 months old.

A few weeks ago the charge state with the original battery began showing 84%
all of the time, even after several hours of attempted charging. However,
the battery apparently was not getting charged because the computer would
not turn on unless the power supply was plugged in. That is, the computer
could not run in battery-only mode.

I replaced the battery, but the computer still would not run unless the
power supply was plugged in. With the new battery, the charge state always
indicates 0%, even after several hours of attempted charging. Thus, for this
new battery as well as the original one, the computer cannot run in
battery-only mode.

Then, thinking that the power supply unit was somehow defective, I tried a
new unit. Nothing changed. Neither battery would charge.

Finally, I tried resetting the power management function (turning off the
computer, holding the power switch down for 1 minute, turning the computer
on, going into the control panel power management function and checking the
status), and all looked normal, but neither the old battery nor the new one
would allow the computer to run in battery-only mode - even after several
hours of attempted charging.

So I contacted HP. All they could tell me was that it is probably a bad
battery charging circuit inside the computer. Getting the notebook repaired,
according to HP, would be in excess of $500.

Then I looked up a few forums on the internet. I was amazed at the number of
battery-charging complaints similar to mine, and not just about HP
notebooks, but about others as well, including Gateway and IBM. From what I
read in these forums, battery charging circuitry failure is fairly common
with many notebook brands.

Any comments, suggestions, and especially problem solutions are most
welcome.

Papa