Hearing aid battery sizes 10, 13, 312, 675 and how to use them

Hearing aid batteries are the thing users buy most often, and the thing they most often buy wrong. Four common sizes look almost identical, yet the wrong size will not power the aid. This guide shows how to identify the right size by number and colour, explains why batteries run down, how to activate and store them so they last longer, and when it makes sense to switch to a rechargeable aid.

Hearing aid battery sizes: numbers and colour codes

Disposable hearing aid batteries are zinc-air button cells. Manufacturers share one colour code on the tab and the packaging, so you only need to remember the number or the colour:

The surest way to know is to check the manual or the box, or take out the old battery and read its number. Once you know the size, browse hearing aid batteries and accessories.

How long do hearing aid batteries last?

There is no fixed figure. Battery life depends on the size, how many hours a day the aid is worn, the volume, whether Bluetooth or noise reduction is switched on, and the humidity. The general rule is that smaller cells run out sooner, so a size 10 usually needs changing before a size 13, and a 675 lasts longest. For the first few changes, note the date on a calendar or phone; you will soon learn how long one battery lasts in your relative's aid and can keep enough spares.

How to fit and activate a battery properly

• Wash and dry your hands first; oil and moisture weaken the contact.
• Peel off the coloured tab. A zinc-air battery starts working once air reaches it.
• Wait about a minute after removing the tab before inserting it, so it activates fully.
• Match the plus sign to the mark on the battery door and close it gently without forcing.
• Once the tab is off, the battery slowly drains even if unused, so do not peel tabs in advance.

Storing batteries for longer life and safety

• Keep batteries in their original pack, somewhere dry at room temperature, not in the bathroom or a hot spot.
• Do not carry them loose with keys or coins, which can short them.
• Open the battery door at night so the aid can air out, and use a drying box or desiccant in humid weather.
• Keep batteries away from children and pets. Button batteries are very dangerous if swallowed; if you suspect a child has swallowed one, go to emergency care immediately.
• Take used batteries to a battery collection point instead of household rubbish.

Low-battery signs, and what to do when the aid goes quiet

Many aids beep when the battery is low. If an aid suddenly gets quieter or stops, check in this order: is it the right size, the right way up, with the tab removed and the door fully closed, and are the ear tip or wax filter blocked? Wipe both faces of the battery and the contacts in the aid with a dry cloth. If a fresh battery still does not work, have the aid checked. Cleaning the tip and filter is covered in how to clean hearing aids.

Should you switch to a rechargeable hearing aid?

Rechargeable aids suit people with shaky hands or weak eyesight who struggle with tiny cells: into the charger at night, out and on in the morning. The trade-off is remembering to charge every day and carrying the case when travelling. Button-cell aids suit people who travel a lot and like having spares in a pocket. If you are torn between the two, try the hearing aid finder or browse hearing aids for seniors.