I think it really depends on the aid and the battery. My gut feeling is that if you have an analog output amp (instead of a class-D digital output amp) then you can notice the fall off. I certainly notice in mine. The part is probably good to less than a volt for current technologies. There is a good online hearing test at digital-recordings.com1 and I like the idea of an A:B comparison suggested.
I was using the Radio Shack 10A batteries up until about a year ago when they switched brands. Now I use Costco … not sure who makes them.
You’re ignoring this member’s posts.