I had been experiencing very poor battery life on my KS9’s over the past several months. I use the Bluetooth pairing to my iPhone Xr pretty heavily. Where I had previously gotten about 3-5 days of use out of each battery, it suddenly dropped to a day or less. In some cases, I would get the initial warning tone within a few hours of replacing a battery.
My suspicion was that a iPhone iOS upgrade had somehow caused the issue, as it happened quite abruptly, and nothing had changed regarding the hearing aids. But that was just a guess.
I went in to get get a new hearing test, with the idea of replacing the KS9’s. As a routine part of that appointment, the HA specialist checked the firmware level. The display indicated that there was a “mandatory firmware upgrade” and she applied that upgrade.
After two days, I realized that I was still running on the batteries I had gone in with. Since then I have been monitoring battery replacement and it is now a reasonable 3-4 days again.
In my case, the firmware was three years old, which is how old my hearing aids were (I had not had any firmware installed since original purchase).
So, if you have older KS9’s, and you use Bluetooth, and you are seeing lousy battery life, go into Costco and insist that they upgrade your KS9 firmware to the latest version.
Older firmware on KS9’s will cause unreasonable battery drain.