Size 312 Hearing Aid Battery

The size 312 battery is sold with a brown colour code and is one of the most widely used hearing aid battery sizes today. It is about 7.9 mm in diameter and 3.6 mm thick: the same diameter as size 13 and the same thickness as size 10. It is a 1.45 V zinc-air battery.

Which hearing aids use 312?

Receiver-in-canal (RIC) devices with a small body behind the ear, mini behind-the-ear models and many in-the-canal (ITC) or in-the-ear (ITE) devices run on size 312 batteries. The Phonak Virto Paradise and Phonak Vitus + BTE Micro are examples of these models. If you do not know your device's battery size, look inside the battery door or in the user guide, or ask our centre.

Average life

A size 312 battery lasts 3-10 days on average, depending on how you use it. In devices that stream phone calls or TV sound over Bluetooth, the battery runs down faster; daily wearing time, the device's power needs and battery quality also play a part.

How to fit the battery

• Remove the protective tab and leave the battery exposed for 1-2 minutes; during this time the battery is activated by the air.
• Hold the device, open the battery door and place the battery with the + (plus) side matching the mark.
• Close the door without forcing it; the device works once the door is closed.

What happens when the battery runs low?

When the voltage drops, the device gives a warning signal. On many models you hear 3 beeps every 10 minutes; if the battery is not changed, sound output switches off with six double beeps when the voltage reaches 0.95 V. Always keep a spare battery with you.

Safe use

Keep batteries away from children, do not throw them into fire and do not charge a non-rechargeable battery; there is a risk of explosion. Switch the device off when you are not using it, take the battery out and leave the door open. Return used batteries to the centre where you bought them.

You can get size 312 batteries from our Pendik centre. If you are looking for a thicker size that lasts longer, see the size 13 battery page, and for all sizes our hearing aid batteries page.