Hearing Aid Battery Sizes
The 7 zinc-air hearing aid sizes, all 1.45 V, sorted by size. They are numbered by size and colour-coded on the pack, and none of them is interchangeable with an alkaline or silver-oxide cell, even where the dimensions match exactly.
Showing 7 of 7 cells.
| Typical mAh | Also sold as | |||||
|---|---|---|---|---|---|---|
| 10 | zinc air (hearing aid) | 1.45 | 5.8 | 3.6 | 91 | AC10, AC10/230, DA10, DA230, ZA10, PR70 |
| 13 | zinc air (hearing aid) | 1.45 | 7.9 | 5.4 | 280 | ZA13, PR48 |
| 312 | zinc air (hearing aid) | 1.45 | 7.9 | 3.6 | 160 | ZA312, PR41 |
| 5 | zinc air (hearing aid) | 1.45 | 5.8 | 2.5 | 33 | AC5, ZA5, PR63 |
| 630 | zinc air (hearing aid) | 1.45 | 15.6 | 6.2 | 1,000 | DA630 |
| 675 | zinc air (hearing aid) | 1.45 | 11.6 | 5.4 | 600 | ZA675, PR44 |
| AC41E | zinc air (hearing aid) | 1.45 | 11.6 | 4.2 | 390 | PR43 |
Capacities are typical values, not a guarantee. Sizes are the measured case dimensions: in a four-digit code the first two digits are the diameter in whole millimetres, rounded down, and the last two are the height in tenths of a millimetre.
Why hearing aid cells are their own category
A zinc-air cell runs on oxygen from the air, drawn in through small holes in the case. That lets it carry far more capacity than any sealed cell of the same size. Size 675 here holds a typical 600 mAh in a case of 11.6 × 5.4 mm, several times what a silver-oxide cell of exactly those dimensions manages.
The cost is that the cell has to breathe, and once it starts it cannot be stopped. The tab on the pack seals the holes, and the cell is dormant while it is on. Peel it off and the cell comes up to voltage within a minute and begins running down from then on, whether the aid is switched on, sitting in a drawer or in its case overnight. Putting the tab back does not reseal it.
Sizes and colours
The sizes are numbered, not measured, so the number tells you nothing about the millimetres; the table above has those. On the pack each size also carries a colour, which is the part most people actually match on.
- Size 5 : Red tab · 5.8 × 2.5 mm
- Size 10 : Yellow tab · 5.8 × 3.6 mm
- Size 312 : Brown tab · 7.9 × 3.6 mm
- Size 13 : Orange tab · 7.9 × 5.4 mm
- Size 675 : Blue tab · 11.6 × 5.4 mm
The same-size trap
Some of these cells share their exact dimensions with an alkaline or silver-oxide cell. Size 675 is 11.6 × 5.4 mm, which is also an LR44 and an SR44. They will drop into each other's holders, and that is the whole problem: the hearing aid expects 1.45 V from a cell built to deliver a steady current for days, and the alkaline cell is neither.
It does not work the other way either. A zinc-air cell in a watch or a toy will start draining the moment the tab comes off and will not hold up under a load it was not built for. Each cell page lists the same-size cells it must not be swapped with, and why.
Storing and handling
Leave the tab on until the moment you need the cell, and store packs at room temperature, away from keys and coins that could bridge the terminals. Do not refrigerate them: that is an old habit that does nothing useful for zinc-air chemistry and risks condensation on the cell. Keep loose cells away from children and pets, and treat a swallowed cell as an emergency.
Questions people ask
- What are the hearing aid battery sizes?
- This chart holds 7: 5, 10, 312, 13, AC41E, 675, 630. They are all zinc-air cells at 1.45 V, and they differ only in the size of the case.
- What do the tab colours mean?
- The colour identifies the size on the pack: Red tab for size 5, Yellow tab for size 10, Brown tab for size 312, Orange tab for size 13, Blue tab for size 675. The tab itself seals the air holes until you are ready to use the cell.
- Can I use an LR44 instead of a 675 hearing aid battery?
- No, and the fact that they are the same size makes it worse, not better. A 675 is a 1.45 V zinc-air cell that breathes through holes in its case; an LR44 is a 1.5 V alkaline cell of the same dimensions. A hearing aid is tuned to the zinc-air cell, and the alkaline cell will not run it properly.
- How long should a hearing aid battery last?
- That depends on the aid and how long it is worn, but the clock starts when the tab comes off, not when the aid is switched on. A zinc-air cell runs down once the air reaches it, whether the aid is in use or not.
- Should I wait after pulling the tab?
- Giving the cell a minute in the open air before you close the aid lets it come up to full voltage. Putting the tab back on does not stop it: once air has reached the cell, it has started.