Motorola A920 Reference Manual page 135

Note: The talk-time, stand-by time and total life cycle of a Motorola
rechargeable battery for your Personal handset will depend on
usage conditions and network configurations. As a consumable
product, the specifications indicate that you should be able to
obtain optimum performance for your Motorola Personal handset
within the first six months from date of purchase and up-to (200)
charges.
The warranty for Motorola rechargeable batteries becomes void if
(i) the batteries are charged other than by Motorola approved
battery chargers specified for the charging of the battery, (ii) any of
the seals on the battery are broken or show evidence of tampering,
(iii) the battery is used in equipment or service other than the
cellular telephone equipment for which it is specified.
Warranty Information - 135