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Why does the battery go flat so fast?

For new users of hearing aids, the shorter-than-expected battery life does come as a surprise. Most of us are familiar with the performance of AA and AAA batteries. Naturally, we expect similar performance from zinc-air hearing aid batteries. Unforunately, this is usually not the case, please read on to find out why.

There are four common sizes of hearing aid batteries: 10, 13, 312 and 675.

The table below shows the ‘capacity’ for each size. Capacity is an indicator of the amount power a battery can contain and is measured in ‘milli amp hours’ (or mAh). The higher the capacity, the more power a battery can supply to your hearing aid.

We have shown the typical capacity for AA and AAA batteries for comparative purposes. It also highlights the fact zinc-air hearing aid batteries have significantly less capacity than AA and AAA batteries.

You will see from the table below size 675 has the highest capacity. Conversely, size 10 has the least capacity.

Let us assume your old hearing aid used size 675 batteries and your new hearing aid uses size 13 batteries. The smaller capacity of the size 13 battery means there is less power available to your hearing aid than if it was using a size 675 battery. The battery life is almost certain to be shorter.

Size Capacity*
AA 2700mAh
AAA 1000mAh
675 650mAh
13 310mAh
312 180mAh
10 100mAh

* Capacity for AA and AAA batteries are based on the Sanyo NiMH rechargeable battery. Capacity for hearing aid batteries are based on the Power One hearing aid battery.

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