How to tell if a ThinkPad 385 battery is good

[skytrain]

New to ThinkPads and bought a 385 XD for a good price, but it has not battery, just the plug in power supply.

There is a warehouse that sells used parts from old lease returns and has batteries from ThinkPads. I can bring my ThinkPad there to try them. How do I tell if a battery is still good and can hold a charge for a reasonable amount of time? Is there a battery monitor?

[rkawakami]

I would think that those batteries have some sort of intelligent charging circuit built into them but I don't know if you can query them with software (i.e. like T2x systems for one) or have a built-in LED to indicate state-of-charge. Without being able to tell how many cycles they have been through or be able to charge and discharge them a couple of times, I don't see any way you could tell the difference. An external date code, if there is one, can only tell you how old it is, not how it's been used (or not).

If I was given the opportunity you have been, I would bring a multimeter along with me. Measure the voltage across the battery's terminals. That at least would give you an idea if there is any voltage in there to begin with. At this point I don't know enough about the internal circuits in the battery to say if you could also safely measure the current being provided. Attempting to put a current meter across the battery's terminal may trigger a short-circuit self-protection circuit inside the battery and render it useless.

[tfflivemb2]

Funny that you ask this. I have a 385XD, and just came across a battery for free from a friend. I was trying to figure out how to test it.

When you insert the battery, and plug in the adapter, there is a light that will either flash orange, be steady orange, or turn green. If it just flashes orange, then the battery will not accept a charge. If it is steady orange or green it will most likely hold some type of charge.

Or in the alternative, if you have an OS installed, you can check what the OS says that it has remaining for a charge. It will not have the same options as the T2x and newer systems, that will display the green battery icon with specific info regarding the battery (ie. cycles, age, etc.).