These batteries work very well until they swell up, put pressure on the hard drive, and cause HDD failure. I read and discounted quite a few horror stories on the web regarding this problem, and now I'm having to send my AV500 in for HDD repair and battery replacement. Archos tech support claimed a 3-month battery warranty although their web site says one year- we'll see what happens when I send it in. Otherwise, it's a great product. Maybe other replacement batteries provide an air gap to prevent the squashed HDD problem, but Archos is still cranking out this same old type. I'm just going to buy more THIN batteries since my 1-yr warranty has almost expired.
Well, I just got my new replacement battery after a 2-wk turnaround- it works, and it's not swollen. I read on the web that you should keep them about 40% charged and stored in a cool place when not in use. The fridge, not the freezer may be a good place if battery is kept dry. I'll try it.