Costco 312 Battery Life Study in KS9s

Just sharing my own battery life study. I received my KS9s 385 days ago and I have always used Costco batteries. I kept every battery I have used and I just counted them today. I have used 174 total batteries in 385 days which works out to 4.425 days average per battery. Not too great.

I wear my hearing aids all day, every day for approximately 14-16 hours and I stream my phone, iPad and tv.

Hopefully someone finds this information useful.


I’ve never heard of 319 batteries.

Sorry, typo 312. I will edit.

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That seems pretty ballparky. I get about 5 days and I don’t wear them for that long.


The 4,425 days of use, we would have to divide it by 2, because 2 aids are used, so it would come out to 2,2125 days per battery, if I’m not mistaken.

Not really. Think of it this way: 174 batteries were used or 87 pairs of batteries. Since they’re used in pairs, divide the 385 days by 87 pairs and ~4.4 days per pair of batteries. Each battery runs a hearing aid for about 4 1/2 days.

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Ok, now I saw it clearly.

Very good contribution an is definitely useful to me. I as well have about 14 hrs average daily use haids. I as well use only Costco battery but size 13 wish I believe is little bigger that 312.

Because I cannot get to that accurate conclusion I was thinking 5 to 6 days is my average. You here allowed me me to confirm this. And I’m okay with anything above 5 days because I do streaming, all my phone call, phone system notifications, changing programs, use the phone landline in combination phone proximity, and I also want sleep with my haids.

I also have Costco KS9’s, wear them all day, roughly 16 hours and do a fair bit of Bluetooth. I get roughly the same life out of the Ray o Vac 312’s. I buy 60 at a time online and in the scale of current prices I’ve stopped fretting about the cost. It’s not much compared to the initial outlay. I even wonder if they will stop making HA’s with disposable batteries. Marketing seems to favour rechargeable but I’m not even sure I would prefer it. You pay a premium for rechargeable which might be more than I’ve spent on batteries in a couple of years.

I also don’t worry about the cost. It was mostly the engineer in me that wanted to collect the data. :grinning:

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My best 312 life dropped from around 6 days to 4-5 days when new aids added bluetooth and I added frequent audiobook listening. In the past 1- 2 years I have had to increase the overall output volume to 80% for better speech understanding, and it is more like 3-4 days now. Still love ‘em though. I work in health care so everyone has at least an N95 mask on…and some have the full spacesuit. I wouldn’t be able to work without them. I do always carry a pack of spare batteries…or preemptively change out the batteries if I will be in a setting where I can’t readily change them.

FWIW, I have KS7’s and my batteries last ~6-7 days each. I wear my aids ~12 hrs/day.

Question: does anyone know where to recycle the expired batteries? I’d hate to just throw them out. I have a small bag full, maybe 200 or so.

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My Costco hearing aid department will take them. I used to get 9 days out of my KS7s.

you could decorate your motorbike jacket with them. HA’s angels?

I have KS8s and wear them 16-17 hours a day. My Costco 312 battery life is the same as yours. I am waiting for the KS10s. I hope theirs is better.

I get about 3 days out of 312 batteries on my Oticon open-s hearing aids which I wear 15-16 hrs a day - constantly streaming.

It seems battery life has gone down since more and more wireless technology is used.

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With the Costco batteries I consistently received a 4 day service life. I switched to RayoVac and saw a battery life increase of 3 days. In that my KS9 now run for 7 days it make remembering when to change out the batteries a scheduled event. Nice

I get about 4.5 days with my K9s and Costco batteries, using the aid for about 15 hours a day, including streaming for 2.5 hours.

I’m surprised at the RayoVac life. I need to try them out…

Where do you buy your Rayovacs? Online? Any particular site?