Can an old battery harm my T41?

[t41user]

I have kept the same 9 cell battery in my T41 for well over 6 months. A 6 cell battery has been sitting unused and uncharged in my carrying case for well over 6 months. Is it dangerous to try putting the 6 cell back in my T41? What if the 6 cell has drained down to zero charge over time? I remember reading somewhere that leaving batteries in a fully drained state for an extended period of time can be dangerous. Which part(s) of my T41 might be damaged? How long have other users left a battery sit before trying to use/recharge it?

[Leon]

it is not good for your battery to store it discharged like that, but using it will not harm your Thinkpad.......

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