The 675 cells are small, button type cells. The chemistry is zinc-air, you
must remove the tab before use. Some manufacturers recommend that you wait
60 seconds before inserting them into the device, to ensure that enough *air*
gets in through the battery holes to react with the *zinc*.
The high power batteries have a slightly higher voltage in high current
circuits. Many circuits cannot tolerate the "sagging" voltage in
the standard 675.
Rayovac has 2 kinds of button Batteries: the 675 and the H675. The H675
battery is optimized for circuits that have a current drain above 10 milliamps.
If the circuit draws less than 10 mA, then the H675 will not last as long
as the standard Rayovac 675.
Most probably don't know how many milliamp their processors draw from the
battery. Here is a simple experiment:
Use Rayovac standard 675 cell and keep track of how many hours it lasts. Do not
count the time when the device is turned off.
Divide 600 by the number of hours the battery lasts. For example, 600
divided by 30 hours equals 20.
If the resulting number is 10 or greater, as in the above example, the H675
should last longer.
Duracell only makes one type of 675 cell which does quite well in both cases. They do so much better
in the higher current applications than do the standard Rayovac 675, that I
suspect that is why Rayovac developed the H675.
Varta brand cells tested about as well as the H675.
The H675, and will *probably* last longer that the standard 675 for
many CI-BTE users.
For some devices (but not all) a Duracell 675 cell may last longer. Keep
track of the number of hours and compare.
For those of you who use AA or triple A batteries, this does not apply. But you
can still compare battery life. For disposable cells, alkaline cells are good,
lithium cells are better, but more expensive.