Dud Rayovac 312 batteries?

Over the last 3 or 4 months my Phonak P90 have experienced 312 battery failure. It’s happened probably about 5 times, most recently yesterday. I’ve cleaned the HA contacts with a fine paint brush soaked in electrical contact cleaner. Yesterday I had low battery bleeps in the left HA. Not absolutely certain whether they had been in the full four days or not, I replaced them with fresh batteries. Within an hour the left one bleeped low battery again. I took the battery out, examined it and shoved it back in. Within 30 minutes I got the low battery bleeps. So fearing a fault with my left HA I swapped batteries between left and right. Within 30 minutes the right HA bleeped low battery and quickly died. I put a meter on the “dead” battery and it measured 1.33v, as high as a new battery. Since yesterday the batteries have been behaving perfectly for more than 24 hours. The batteries are Rayovac 312 supplied by my audiologist with expiry Jan 2025. Has anyone else experienced querky battery behaviour?

Interesting, my brother used to using Rayovac 312 but he preferred Duracell (Oticon Agile Pro/Acto minRITE), not sure he had what you described.
Now he uses 675 and prefers Power One Evolution (Phonak Naida UP BTE).

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I’m not an electrical engineer by any means but it could be possible that the batch of batteries you purchased may not be reaching peak power levels properly under draw. I would suggest trying a different brand of batteries or buying the same batteries to confirm what’s going on.


It kinda undermines the security I used to feel with batteries; if they were to die during an important moment, like in a theatre after having paid £££ for a ticket, I could whip out my emergency set from my wallet. What if my emergency set were duds?

I seem to have the same problem with costco batteries. Not sure who makes them for costco. I have no real way of knowing if this is correct but it seems the tiny holes may be too small to let in enough air. Made worse by living at over 6000 ft. Water doesn’t even boil right here. LOL

If they die prematurely I blow on the hole side let it sit for a few minutes and often they work for a few more hours.

Your mileage may vary.

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I do not do it but I have seen instructions that you are supposed to wait 5 minutes after unsealing a battery to get optimal life.

The current Ray-O-Vac Extra days one minute for best results.

I give them about a minute after peeling the foil off before fitting to HAs.

Back last year, the VA changed to Ray-o-Vac and I started having problems with Ha’s rebooting and sometimes giving false low voltage sound. I noticed that it would do that if I bumped them. I measured the thickness of a couple of each and the Ray-o-Vac were (very) slightly thinner. Very small sample size so it could just be a fluke but I bought a box of Power Ones from the owner of this website and I haven’t had a problem since. I am getting new aids in a couple of weeks.

Thinner could explain it. I was some what confused when my voltage meter read 1.33v on the “dead” battery.

Why don’t you get the hearing aids looked at.

Because I have identified the fault being with the batteries when I swap batteries from right to left and vice versa.

My protocol was to first go with Duracell. I’d tried various other brands, but found the reliability of Duracell was superior. Next, I peel the sticker off the battery, RUB the head of the battery on any cloth nearby (in case there’s sticky residue from the tab), and let it sit 2-4 minutes before inserting. It seemed like a voodoo ritual, but over many years’ trial and error, that seemed to ensure the best battery life.