My experience is similarly disappointing. Size 13 ZPowers in Unitron Moxi All 600s simply couldn’t last a full day, and they have exasperating quirks.
With good-quality disposables properly aired, I got 60 hours (4 full days with about 3 hours streaming per day) The disposables are rated about 300mAh, and the ZPowers 40. Therefore the ZPowers should only be expected to last about 8 hrs of my use. They usually did better than that, perhaps an average of 10, bluetooth side always dying first. I once got 15 hours with no app or streaming, but then the recharge was about 11 so the aids weren’t available next morning.
I read that updating the charger firmware was sometimes a solution so I tried that. The utility reported that some chargers couldn’t be updated, and to contact audi. I asked for further info from ZPower, got three different answers, all telling me to contact audi Two of the replies offered a link to the firmware utility that I’d already told them didn’t work. Third answer was that the size 13 charger can’t be updated.
I got $200US back from the vendor as compensation and switched to disposables. Currently my wife is wearing the aids part time, and the ZPowers are making it through her short day. Yesterday she wore them longer, 10 hours. The ZPowers made it through but then took 10 hours to recharge. A few days ago they seemed to charge OK, but the left was blinking red in the morning. A week ago they indicated fully charged, but one was dead. What a pain. My wife will probably switch to disposables after the next quirk.
Bottom line, Unitron should never have sold the ZPower system without a caveat that it’s only good for part time use. I note that ZPower is now touting full days from their Gen2 version. But isn’t that what they implied with Gen1? So no more ZPower or Unitron for us.
I’m now wearing Phonak Marvels with lithium ion. Same use pattern as the Unitrons, but the Marvels are still at 60% after a 15 hour day. Very happy with that.
Rechargeable batteries are everywhere, even in my whole house backup system and my car, which has like-new batteries that are 7 years old. Nothing wrong with the concept of rechargeables, only ZPower’s crummy implementation.