I Need a repetitive warning sound (Wav.) when my battery needs recharging.

I do have the freeware Batti 2.4 however this only gives a single warning sound at Battery-low and one further single warning at critical, and even then only when it is not asleep! As I often leave my Diamond on my desk at home for two or three days at a time without even going to it (unless someone rings me) I forget to check if it needs re-charging, previously it has gone flat and turned itself off without me realising.

By playing with the registry I did manage to make visible under Sounds & Notifications /Event: the Low Battery warning settings, however I set a loud sound and checked repeat, then when the battery droped to 10% the sounds at first come every few seconds (most annoying) with their frequency gradually diminishing and then desisting after about 15 minutes, no good to me if I’m not in earshot during that 15 minutes I would prefer them to continue indefinitely at 4 minute intervals or until I interact on the low battery warning.

Can anyone either help with the Reg Settings or suggest something to help please?