Dell 9200 laptop will not run on battery

I have a Dell 9200 laptop. Yes it is rather old, but has served me well. It had been in storage about a year. It works fine if the PSU is connected. It shows the battery is fully charged. The battery test lights show the battery is fully charged. But, the computer will not boot up or stay on with just the battery.

Sometimes it will start to boot, then just turn off. If I boot up with the PSU and disconnect it, the computer will stay on for about minute, click and turn off. Then it will not even attempt to start if press the power button. If I plug in the PSU, all is well.

Any thoughts?

 

I'm thinking possibly memory effect in an old NiCd cell, but it's old. You can try putting the battery in a Ziploc bag, squeeze all the air out, and freeze it for about a week. This will break up any crystals which may have formed inside of the cells. More likely though is that it has reached the upper limit of it's discharge cycles.

I also do recommend that if you're not running strictly on battery, to run the PC on AC only with the battery removed. It is a real possibility that the battery is toast, and you're getting a false positive from the diagnostic circuit.

But, I'd definitely freeze it first just to find out...

 

Thanks, mekanic,
The battery is Li-ion. But, it sat without recharging for about a year. I am just a bit confused because the battery test and the PC show the battery is charged. When the computer turns off, it doesn't show a low battery shutdown. It just makes a click and is off.

I don't mind buying a new battery. I'd just hate to spend the money on a battery and find out it's something else. Is there anything that could cause a laptop to run fine on AC, but not work on a good battery?

 

Its possible the hardware used to charge the battery is bad, but that is very unlikely. It is more likely that the battery is gone as already mentioned. This is exactly how a bad battery behaves. It shows full charge (or none sometimes), and then when you remove AC, the machine instantly turns off.

 

Thanks Adrynalyne,
It's what I was thinking. Since the machine works normally off the AC and dies almost immediately when on the battery, the battery is the likely suspect. I'll spring for a new battery. It was the false information about a full charge that was confusing me.

 

Just FYI, I replaced the battery and the laptop works fine.

 

I was going to go into my daughters dell problem and how my bikes battery dies in the same way but you got it fixed so i guess, like joey, my point is moo.

Glad you got it fixed though!