Size 675 (blue) vs Size 13 (orange)
Size 675 and size 13 are both 1.45 volt zinc-air hearing aid cells, and both are 5.4 mm tall. Diameter separates them: the 675 is 11.6 mm across with 600 to 650 mAh, the 13 is 7.9 mm with 280 to 310. They fit different aids and cannot be swapped.
| Size 675 (blue) | Size 13 (orange) | |
|---|---|---|
| Chemistry | Zinc-air | Zinc-air |
| Voltage | 1.45 V | 1.45 V |
| Diameter | 11.6 mm | 7.9 mm |
| Height | 5.4 mm | 5.4 mm |
| Capacity | 600-650 mAh | 280-310 mAh |
| Also sold as | PR44, ZA675, 675A, DA675 | PR48, ZA13, 13A, DA13 |
Tab colour is the fastest check at the pharmacy shelf. The 675 carries a blue tab and the 13 an orange one, a code every manufacturer follows. Size 675 is the largest standard hearing aid battery, used in power behind-the-ear aids and cochlear implant processors, and it runs nine to twenty days. Size 13, the workhorse for behind-the-ear and full-shell in-the-ear aids, runs six to fourteen.
Because the diameters differ by nearly 4 mm, there is no swapping in either direction. A 13 rattles in a 675 door and will not make contact, and a 675 will not enter a 13 compartment at all. Your aid takes exactly one size, and it is printed in the manual and usually on the battery door.
Two cautions specific to these cells. The 675 shares its case dimensions with the LR44 and SR44 button family, but an LR44 in a hearing aid sags immediately under the load, because zinc-air delivers far more energy at a lower 1.45 volts and needs its air holes to breathe. Cochlear implant users often need the special high-power 675 variants their processor maker specifies. With any zinc-air cell, peel the tab, wait about a minute for air to activate it, then insert.