Need help with cordless phone rechargeable battery replacements.

Found 10th Mar 2008
I have a BT Synergy 3505 cordless phone that used to have Uniross Nimh rechargeable batteries (700maH) but they had died. So i brought some Uniross rechargeable batteries but they are 1000MaH and after 12 hours of charging they do not work. Why is this? Do I need 700maH batteries instead?

Thx for ur time


maybe it wasnt the batteries failing but the charger?
try cleaning phone/charger/battery contacts with a cotton bud and meths/surgical spirit

Original Poster

Thx for the tip but I have cleaned it all and checked that it works with some older batteries.

nope pretty much same batteries so must have a couple of duff en's in, charge em n put a multimeter on each, mah is just how much they can store vs drain time

Could those new batteries be of different chemistry (i.e. NiMH when your old ones were NiCD)?

Anyway, take a look at possible replacements:…505
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