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
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 4˝ 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
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 1˝ 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
22˝, 30, or 45 volts.
45 volt batteries were used from around 1940 to around 1946.
30 volt batteries were used from around 1942 right up to 1953.
22˝ volt batteries were used from around 1947 to 1953.
15 volt batteries were used from around 1947 to 1953.
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.