Steady static noise

Almost a year I am wearing Oticon EPOQ XW 1.1 hearing aids. Few months ago one of HA started to generate the static noise.
At the beginning I considered that somewhere is playing the radio. Then static noise has been started to trouble me more and more often in a car, outside –anywhere.
The consistency is only one. With new battery hearing aid generates the static noise after one day or 5-9 hours of HA using. If the battery is not new, 4-5 days old, the static whistle started after 1-2 hours. I cannot take it for long time and always turned my hearing aid off. Then in a hour it repeated again. I cannot use my HA.
I have seen my audiologist and he changed the HA receiver. I am keeping my HA within Super Dri- Aid. But unfortunately the steady static noise is appeared again.

Could you advice me something?

Thank you very much.

Yes. Eliminate the obvious.

The aids are in warranty, so send them back to Oticon for checking and possible repair/replacement.

If they are then STILL hissing post here again.