There were different symptoms.
In all cases, the HA that ailed (one failed at a time) became “upairded” from the APP. With the battery units, the HA continued to function about 1/2 the time - with no connection if she was on the phone. If she was using the HA standalone, the sound seemed to “change texture” (according to her) and go to the default (all around) program.
There is no easy way to restart the rechargeable hearing aids, although it is possible.
With the battery units, she discovered that if she opened the battery door, waited, and closed the door, the HA returned to normal including re-pairing with the app. It then lasted the remaining estimated time for the battery - typically more than a day.
We don’t think the battery or charger was at fault with the rechargeable units. Once the problem started, she began examining the app during they to note the battery level. It was always at full after an overnight charge and typically declined to nearly full when examined as the day went on. Clearly, she could not examine the level at the instant before the failure.
She, in one case, experienced the first failure, of a rechargeable, on the ride home from the Audiologist after the first week adjustment.
She does not use a HA dryer but stores the battery units in the Resound-provided case overnight.
She has many years experience with non-rechargeable zinc/air batteries and has been instructed to allow them to sit a bit after removing the seal. I don’t know the exact time, but I don’t believe it is critical after the batteries have been in successful operation for an hour or more.
She has been trained to wash and dry her hands before changing batteries and avoid touching the air vent, so it doesn’t clog. After a period of correct operation, it is likely the air vent is not the problem.
She typically gets 2 days or more out of the non-rechargeables. The rechargeables were nearly depleted each day before going back on charge. I discussed the rapid discharge issue with a Resound tech support person and was told the 30 hour estimate of battery life was measured in a non-streaming mode. Since she uses her iPhone for calls, occasional Zoom meetings, and some TV, Resound suggested a mid-day recharge during, for example, a nap. She never got to try this.
The problem occurred at least once after the audiologist removed M&IRE.
She picks up her Resound One 9 with M&IRE today. Hopefully the battery problem is a manufacturing defect on the Omnia and the older One’s will work as advertised.