The size is printed in the manual or inside the battery door. A 675 has a blue tab. The four brands are interchangeable, size and voltage are the same.
Why wait after removing the tab?
A zinc-air cell activates on contact with air. Leave it in the open for a minute or two before closing the door, so it reaches full voltage.
How long does a 675 last?
Roughly one to three weeks, depending on the aid's power, the volume and the hours worn each day. Bluetooth streaming drains it faster.
How should I store the batteries?
In their blister pack with the tab on, at room temperature. Avoid the fridge, moisture harms zinc-air cells. Do not keep them loose with coins or keys.
Which 675 battery for a hearing aid?
The 675 is the largest of the common hearing aid batteries. It is easy to spot by its blue tab. It mainly powers strong behind-the-ear aids, which need more energy than small in-the-ear models.
The four brands on offer, Renata, Varta, Rayovac Extra and Maxell, sell the 675 in packs of 6. All are zinc-air cells of about 1.45 V, interchangeable from one brand to another.
A zinc-air cell stays inactive while its tab is on. Peel it only when you need the battery and keep the others in the pack. Spent batteries go to a collection point, not in the bin.
