Our BT cordless phone is being a minnie - if you leave it off the base for even a short while and someone calls, when you press the answer button the handset just dies for a few seconds.

I suspect the battery as if you use it straight from the base everything is ok.

Now the question is - can I use any type of rechargeable battery - it takes AA but I think only 900mah and I have some 2000mah lying around.....

You should use the same type- Ni Cad or Lithium-Ion (charging currents are different), as the originals, but the capacity shouldn't matter.

Do a Google on the type of phone /battery --should tell you type of cells -i.e Ni Mh /Ni Cad etc . That's the only difference - from memory NiCad are 1.2 v charged whereas NiMh are 1.5 ---the capacity means that it holds more charge ( last longer off the charger ).BTW -you could try letting the battery die and then recharging it (if as i suspect it's Nicad )---to try and remove the memory effect .

^ you'll be able to get a replacement battery pack quite cheap.

eg - Cordless Phone Batteries at Battery Force

Thanks all - I wasn't aware there were two types, I was just worried about the capacity. It takes normal AA so easy to replace - I just need to find the right ones.