With modern Lithium Ion batteries (as in the CS30x0) I regulary hear 300-400 full charge cycles being quoted for MCD etc. A full cycle being a full battery, used to 0% then re-charged to 100% capasity. The question becomes how long in their use profile does it take to do 400 cycles? 1 cycle per day is a little over 13 months...if they work weekends!!!!....but allow for natural decay of the checmicals, 1 cycle per week is not going to last 8 years....so it really depends on how they use, store and charge the device. 300-400 is a very rough guide. 18 months - 2 years? Ask them how long the battery in their consumer phone lasts? or laptop? Does it last the life time of the hardware....I have never needed to put a new battery in a phone or laptop...the rest of the hardware fails first.

I want to know when we need to replace thebattery

Shridar, If we do 500 cycles of charge, 500 x 3 hours = 1500 hours. If we use at maximum load (8 hours) = 500 x 8 = 4000 hours The total is something like 5500 hours or 229 days at least. Rgds Roberto Mielle

Shridar, Normally i use 500 cycles of charge and the autonomy in Full Charge (for 8 hours at 6 scans per minute) Rgds Roberto Mielle