Battery Meter keeps dropping to zero then back up, but the laptop keeps running fine. (HP...

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I have a HP pavilion zd7000 laptop.

The little battery meter sometimes shows the
correct charge, but usually falsely reads zero.
It says zero most of the time, but then
occasionally jumps up to 100% or 90% or whatever
the battery is currently at, then a minute or
two later it's showing zero again.

When this first started happeneing, it made the
computer unusable because it would see the "fact"
that the battery was dead, and panic itself into
an immediate shutdown.  I assumed there really was
something wrong with the battery, like it wasn't
holding a charge.  I believed that it really was
failing to get power to the computer, or had an
intermittent connection that kept losing contact.

But when I turned off all the OS's low-power-panic
features, I found that it runs just fine on the
battery, and there is plenty of charge there to run
it a couple of hours- its just that the computer
can't seem to measure it.

Is this unique?  Have other people had this problem?

Oh, and another thing - when I have the AC plugged in,
it DOES charge the battery, even when the meter says
it's not having any effect.  (I can tell because when
it occasionally shows a nonzero number, the nonzero
number it shows is a bit higher than it was the last
time a nonzero number showed up, so I know it is

Also, I can sometimes reliably get it to toggle between
0 and 100 % based on how I tilt the computer.

Clearly some connection is spotty, but which one?  The
connection that carries the power seems to work fine.

I used to believe it was a software problem with my
battery meter program (I usually run Linux, which at
the time had poor support for APM and ACPI), but I
get the exact same behavior from Windows XP, so now
I think it's a hardware problem.

Re: Battery Meter keeps dropping to zero then back up, but the laptop keeps running fine. (HP Pavilion zd7000)

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Oddly enough I had EXACTLY the same problem with a ZE4805WM laptop. I
had really weird luck with eBay batteries for this machine. The factory
battery was perfect. Battery #1 from eBay would usually give a charge
error (flashing yellow LED) but if wiggled right would work perfectly
until jolted, at which time it would go into error mode again (but
would still power the machine). Battery #2 would give the symptom you

In both cases the problem was dry solder joints on the I2C lines inside
the battery. Although there is no guarantee the LOCATION of the problem
is the same for you, the chances are >95% that the SOURCE of the
problem is the same.

It would be very instructive if you could isolate it to either the
laptop or the battery by trying another battery.

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