I purchased a set of Phonak Brios at Costco in Jan 2016 and was given a package of Kirkland 312 cells. After about a week, the HA’s would give me a warning tone about 20 min before they shut down and a final tone when they did. I tried other batteries to experiment with. Power One cells worked ok, (these were given to me in my trisl of Resound Linx 2s) but Energizer cells made the Brios shut down erratically towards the end of their life.
I asked my Costco Audiologist about batteries and she commented that Kirland cells “were Rayovac and very inexpensive so why would I want to buy anything else.”
Indeed, it appears that the Kirkland cells are a great deal and appear to work well with the Brios and I seem to have read that Rayovac is recommended by Phonak for this model.
In my experience though, it appears that exposure to moisture seems to shorten the life of zinc air cells. I wasn’t advised to, but I purchased a dryer unit. I think that this may help protect my HA’s from corrosion and the batteries in better working order.