Eveready E400 Mercury Hearing Aid Battery
The Eveready E400 1.4 volt mercury battery was manufactured by the
Union Carbide Corp of New York, NY for behind-the-ear hearing aids
from the mid 1950s? until hearing aids standardized on 4 basic sizes of
batteries around 1980 or so. This battery weighed less than 1 g and
measured 0.455" in diameter by 0.135" high. It had a capacity
of 75 mAh. |
 |
Click picture for larger view |
| |
 
|
| |
|
|
Top view of the Eveready E400 mercury battery showing the positive
terminal. Patent number 2542575 was filed in 1946 and issued in 1951.
|
 |
Click picture for larger view |
| |
|
|
Bottom view of the Eveready E400 mercury battery. The bottom and sides
comprised the negative terminal of the battery.
|
 |
Click picture for larger view |
| |
|
|
The Eveready E400 mercury batteries were sold in blister paks of 6
batteries each. It seems the E400 battery was a newer version of the
older E400E battery, but they appear to be identical from the outside
and in function.
These batteries probably date from the 1970s.
|
 |
Click picture for larger view |
| |
|
|
Bottom view of the Eveready E400 mercury battery pak.
|
 |
Click picture for larger view |
| |
|
(If a larger picture doesn't appear, you may have to
turn your pop-up blocker off)
|
|
|
