T500 not powering on with battery plugged in (update)

[gravy robber]

My T500 won't boot with the battery attached. Boots fine with no battery and just A/C.

When I try to turn it on, most of the green power lights (bluetooth, wifi, z thing, battery, etc) flash in some order, either the hard drive or optical drive starts spinning then stops, then nothing. No BIOS screen. Just the battery and z thing light remain on until I remove battery.

My initial feeling is it's a bad battery... but it had so much capacity left and was working until the last time I shut it down! Doing the 1-second intermittent power button and then holding worked to get it working again with just A/C.

Are there any other possibilities I can do to get the battery working again? I really don't want to have to order a new battery ...

Update: I tried sticking the battery in while it was booted and running (arrest me). It would run off whatever charge was left when I disconnected the AC but it wouldn't boot after I shut down and the battery didn't seem to charge while running.

[Brad]

Is the battery an OEM Lenovo battery?

Brad

[Saucey]

I had an ultrabay battery that had a similar fate on a T61.
Wouldn't boot at all, even with a working battery and wouldn't charged either.
Removing the battery the machine would boot.
What's funny is that I think it drained my battery when testing it on an X61T w/dock.
I think it showed error under Lenovo Power manager when I checked it.

Also the regular battery from the X61T died on me as well a month afterward... Healthy, still had like 40 cycles. My guess is that it didn't like being charged with a car charger from a W500.

[gravy robber]

It is an OEM battery. I haven't used a dock or anything other than the charger included.

I stuck it in the freezer for 12 hours as a last resort and it's now coming back to room temperature.

A few hours later it's now charging again!