How long should batteries last after unsealing, if not used?

If I was to take the tab off a battery (I use 312s), but not use it, how long would it be till it was completely flat?

My batteries usually last about 8 days, and I recently started changing them every Saturday instead of waiting for them to beep. As an experiment, I put last week’s old batteries aside. A week later I put them back in again to see if they still had any power. They both powered up the aids, but soon beeped to say they were nearly flat. Ie I used them for a week, and a week after that they still weren’t completely dead.

I’m wondering how safe it is to just throw the old ones in the pile now that I’m not using them till they’re dead. Is there any danger of heat building up if they short circuit in the pile?

I put mine in a small plastic bag with other dead batteries and take them in for recycling every couple of months. I change both batteries when the first one dies.

I’ve never had problems with short circuit. I just put all my old batteries in a cup, and then take them away a few times a year. I also replace both when one complains about power, however I don’t do it like weekly, I just do it whenever it runs out.

The worst thing I’ve experienced was some old batteries i left at work in the package in a sunny place. They started to leak some white powder-like looking substance. It also happens very rarely sometimes i my battery cup.

I would say you’re safe. Don’t worry about it :smiley:

I would think that if you unseal a battery, the oxidation process will start a slow self discharging drain on it. While I don’t know exactly how long it’ll take before they’re completely self discharged, I would guess that it’ll take a few weeks to a month.

But as long as you drain it quicker than its self discharging rate does, then the amount drained through the self discharging is negligible compared to the real drain due to normal use.

As to why stale and used batteries still hold enough charge to start up your hearing aid, although only momentarily before they are drained, I think when unloaded, the chemical process pushes the voltage back up to above the operating threshold., but there’s no real juice left to maintain that voltage if a new load is applied. So as soon as a load is put on it, it fails to perform and deliver the necessary current to the load, hence the voltage is dragged back down below to operating threshold, causing the hearing aid to shut down (again).

As far as any danger due to short circuit of an old battery, not really because it’s such a small battery that there’s really not enough energy left to overheat anything enough to start a fire.

Just a piece of the question:
I ran a test with 312 battery/KS7 aids by puting new batteries in and never turning the aids off. Aids went into dryer/sterilizer every night , as usual. Batteries lasted 6 days.

My normal battery life is 8 - 9 days (opening the battery drawers each night in the dryer).

I would guess open. unused batteries would last around 2 weeks.