On Sun, 14 Aug 2011 21:49:59 +0100
Roger Mills wrote:

My 8-year-old HP/Compaq nx9005 laptop has got a completely flat
battery
- or, rather, *two* completely flat batteries, because I bought a new
one a few years ago and they are now both the same.

The power arrangements for this laptop are as follows:

The battery is lithium-ion, 14.8v, 4400mAH (type F4809). It has a row
of LEDs on the side to indicate the state of charge.

The mains power supply delivers 18.5vDC through a cylindrical
connector, which powers the laptop when on mains, and charges the
battery via circuitry built into the laptop. There is a light on the
front of the laptop which is amber when the battery is charging, and
turns green when it is fully charged.

Well, that's what's *supposed* to happen. What *actually* happens is
this:

If I 'charge' the battery for (say) 24 hours, the lamp is amber for
the whole time and never turns green. If I remove the battery
immediately after 'charging', it is stone cold and none of the charge
indicator LEDs light when the test button is pressed.

Even after a long charging period, the battery won't start the laptop
if mains power is not present. If when the laptop is running, mains
power is removed, it stops dead.

If I run the laptop without a battery present, the charge lamp
flashes amber (but is solid amber if a battery is present).

I have tried putting one of the batteries in the freezer for 2 days,
and then thawing it and attempting to charge it - all to no avail.

Sorry for the long pre-amble! My question is this:

How can I tell whether the problem lies with the battery or with the
internal charger? Are there any clues in what I have written above? I
don't mind buying another new battery but, if the charger is duff, I
will have wasted my money.

I usually run it on mains anyway, so it's not a total disaster if I
can't make the battery work - but one does tend to expect a laptop to
have its own built-in UPS!

TIA.

I have a similar situation to you. My laptop is an nx9010, and I bought
a new replacement battery just over a year and a half ago. Now it
behaves exactly as you describe, in every detail, and I also have
wondered whether it's the battery or the charging system. I shall be
interested in the conclusion, if any, although I have bought a new
laptop, which far outstrips the abilities of the Compaq.
--
Davey.