[MaKSiNG]

Hi All,

Not sure this is entirely the right place to ask this question but I guess it is more of a general battery question anyway.

I have an old BT Synergy 3505 cordless home phone with answer machine. The batteries in the handset are due for replacement. The batteries that were supplied with the handset are 2 non-branded 1.2V 550mAh AAA Ni-MH batteries.

Now I thought any rechargeable AAA battery would work. However, I have tried both Duracell 1.2V 900mAh AAA Ni-MH and Duracell 1.2V 1000mAh AAA Ni-MH batteries. These do not seem to power the handset and neither will they charge when placed in the charger/base unit.

As far as I am aware the mAh value does not matter, is there anything else to observe when buying replacement batteries?

TIA,
MaKS

[MarkE19]

Are the replacement AAA batteries brand new and never before charged? If so you may find that the charging in the phone isn't powerfull enough to give the batteries an initial charge. You could charge them in a separate charger and then see if they work in the handset and recharge themselves.

Mark.

[MaKSiNG]

Thanks for your response Mark.
The Duracell batteries aren't new though and do hold charge already. They simply do not power the handset.

After a little bit of browsing I have just found a post elsewhere that might answer my own question.
It seems that BT cordless handsets will not work with batteries that are more than 880mAh. Not sure why but this would be but its consistent with my findings. I am going to order some new rechargable batteries of 700mAh and see if they work.

[prking]

I believe this is due to the (low) internal resistance of the battery.