Hearing Aid Batteries—General Information

Hearing aid batteries have changed dramatically in size over the years. By today’s standards hearing aid batteries of the past were huge.

Carbon hearing aids, which were the first to appear on the market, required heavy currents to produce the amplification necessary in the hearing aid. These usually used battery voltages of 3 to 4½ Volts, sometimes 6 Volts. Because of the high current drain, these batteries usually lasted about 2 to 3 days maximum depending upon the make of hearing aid, the number of microphones in the hearing aid and the hours of use.

These batteries were generally worn separately from the hearing aid—either in a pocket or strapped to the body. There were a few models of carbon hearing aids that had self contained batteries, but these units were relatively large. There were also a few manufacturers that offered rechargeable lead acid cells for their carbon hearing aids.

When vacuum tube hearing aids appeared in the late 1930s and early 1940s, batteries were still relatively large. These hearing aids required two batteries to provide power. The "A" battery powered the vacuum tube filaments. These depleted rapidly because of the high current drain for the filaments.

Here is an example of an ad for the Burgess line of hearing aid batteries from about 1940. Page 1 shows carbon hearing aid batteries, while page 2 shows their line of vacuum tube hearing aid batteries.

Hearing aid users were often advised to keep two or three batteries on hand and rotate them daily to allow them time to recover. Even so, these batteries, usually 1½ volts, rarely lasted more than 3 or 4 days of use.

The "B" batteries used to power the plate circuits for the vacuum tubes used relatively less current and thus they could last up to a couple of weeks before needing replacement. The "B" batteries were generally either 22½, 30, or 45 volts.

After the mid 1940s, better vacuum tube design reduced the current consumption of the vacuum tubes for both the "A" and "B" batteries. Manufacturers were then able to produce smaller sized batteries which could be self contained in the hearing aid eliminating the need to wear a separate battery pack to power the aid.
 

Here is an example of an ad in the Saturday Evening Post, January 22, 1949, showing batteries from this period. The ad shows an Eveready 420E 22½ volt "B" (left) and an Eveready 1035 1½ volt "A" battery (right).

Transistorized hearing aids in the 1950s sounded the death knell of the high voltage "B" batteries. The transistor hearing aids only required a single battery for power. These were generally 1½ volt alkaline batteries or the higher current 1.4 volt mercury battery.

The batteries came in a number of sizes from the double "A" size we are familiar with today to the smaller mercury batteries pictured in the collection.

Mercury batteries for hearing aids are no longer manufactured for hearing aids due to environmental concerns about the large quantities of mercury contained in each cell.

Modern hearing aids, of course use the small button cells, mostly zinc-air, that come in many sizes for the various styles of hearing aids. The common sizes in use today are the 675 (blue tab), 13 (orange tab), 312 (brown tab) and 10 (yellow tab). There is even a tiny number 5 (red tab) battery.