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:

  1. 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.
  2. Divide 600 by the number of hours the battery lasts.  For example, 600 divided by 30 hours equals 20.
  3. 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.

I've written several posts regarding batteries for the CI-Circle. Battery quality varies amongst manufacturers and unless Consumer Reports does an article on them, it's hard for the layman to tell them apart one from the other. Short of writing to each manufacturer and asking them for the discharge curves on their product to make the comparisons yourself, let me give you several pointers:

1. Look for a nickel metal hydride battery (NiMH), NOT a nickel-cadmium (NiCAD) cell. ... lots of reasons and "memory" problems is just one. 
2. Standard, over-the-counter, use once and throw away alkaline batteries provide 1500 milli-amp hours (mAh) of current at 1.5 volts ... about 2.25 watts of power (Ohm's Law: Watts equals volts times amps... 1.5 x 1.5 = 2.25). 
3. Rechargeable NiCAD and NiMH cells provide 1.2 volts and can be purchased with 1200 mAh ratings ... about 1.44 watts. (I'm told higher current ratings (up to 1600 mAh) are out there on the market but I haven't really sought one out lately.) 
4. Most stores sell cheap NiMH and NiCAD cells providing only 850 mAh or 1.02 watts of power. 
5. The higher the power, the longer the battery will last in your child's processor.
6. It is important that you recharge these batteries in chargers certified for NiMH cells because of the charge rate differences.

Use the guidelines I've suggested and check the specifications on the product you are considering. My son has been using Radio Shack 1200 mAh NiMH cells in his processor for nearly 2 years and we recharge them in the NiCAD charger Cochlear sent with his processor. Don't spend a lot of money if you don't have to.

Battery Case from Lloyds

Solar Button Cell Hearing Aid Battery Charger?