@jim_lewis my only issue with rechargeable batteries is despite claims of 800 cycles for an iPhone (I wish ill see that) is that expecting 5 years out of a Li battery that you wear and charge nightly would mean 1,825 charge cycles. That’s a lot. If you could point me towards battery info that supports that I’d appreciate it as I haven’t seen that. My question wasn’t about whether that’s even achievable, but how easy will battery replacement be. If it’s simple, something your audi can do in house, then that’s a big plus. If it has to be sent back to the factory, I’d be curious on turnaround time. I think rechargeable HAs have a lot going for them, especially keeping the interior sealed up which should allow for better moisture protection.
As to cold temperatures, I was simply pointing out that all Li batteries will deliver less current. You will likely be recharging sooner than at warmer temps. I’m not sure your ear is enough to keep them warm. It’s true across the board so any prolonged use in cold temps will drain them faster. Granted, there may not be a ton of folks who are outside in cold weather for 8-12 hours a day, but for those who are, finding a way to protect them without interfering with performance may help get a few extra hours out of it before ready to place back on a charger.
I think the future is for rechargeables replacing button batteries on next gen HAs. It’s fine with me as the little button batteries have their drawbacks. But rechargeables aren’t without their own limitations which hopefully will be addressed over time.