Timothy Murphy wrote:
Harry Bloomfield wrote:

I got 3 of these Friedland wireless bells, and would only give them 8/10.
The batteries run out quite quickly
(I use rechargeables, and they last about a fortnight).
It only rings once, when the bell-push is pressed;
and the sound is not very loud.

That is the wrong type of use for rechargeable batteries. They are best
used for something which will quite quickly discharge them. The primary
cells (none rechargeable batteries) in bells, remote controls and
similar should last for many months or even years if you use good
quality ones. Our cordless bell has been installed about four years and
is still on the original set of batteries.

I know this theory about the limits of rechargeable batteries,
but I use them all the time, in everything (except smoke alarms).
I find they work perfectly well in devices that claim otherwise,
eg TV remote controls and wireless computer mice.

NiMH cells are especially poor for this service.
They will often be essentially dead at 6 months.
NiCd is significantly better, usually having power at 12 months. (IME)