Acer aspire one battery discharges when powered off

I have an Acer Aspire One D250. If I fully charge the battery and leave it in the powered-down (i.e. not in standby) laptop, the battery discharges over about 3 days.
I tried charging the battery and leaving it out of the laptop for three days and it only lost negligible charge.
Acer won't give me a direct answer as to whether this is faulty behaviour.
Does anyone else see this sort of behaviour?

Thanks for the spam markboy

I sent my Aspire One to Acer support to be "tested". They had the unit for about 24 hours, in which time they somehow concluded the battery did not discharge over 4 days, but at least had the courtesy to re-format my hard drive. Although I know it's not the battery, they have said they're sending me a new one, so at least I can now have a spare on hand.