Batteries for DECT phones

["Tim Hawes" <timsyahoo@xxxxxxxxxxxxxx>]

Our DECT phone batteries are dying and we can barely have a decent
conversation without the call being dropped. The phones use AAA size
NiMH batteries, but is there anything special about them for phones?

e.g. CPC have this 4-pack for =A36.25+vat, @ 850mAh rating (BT03464,
general AAA "consumer" batteries), but also:
BT02561 @ 650mAh rating for =A32.96+vat *each*, i.e twice the price and
for less capacity, but stated to be for DECT handsets.

Is there any reason why I have to use a battery designated for phones
as they appear to be just more expensive?

Thanks,

Tim.