These two batteries are not the same, and its not just because they have a different brand.
Its been an ongoing battle lately. You see, I have a Mac Mini, Bluetooth keyboard and a magic mouse, all by Apple. All working harmoniously until something strange started happening.
In the beginning I blamed my upgrade to OSX Lion; it just happened to coincide with my recent upgrade, that my mouse started to play up.
Like many, my first instinct was to replace the batteries and this was in fact the correct instinct.
But what followed was an ongoing saga that left me demoralised and threatening to see if my magic mouse could magically fly. Mice don’t fly, and I decided against it in the end. Had I taken my mouse to a doctor, I’d have described the symptoms as follows;
“its started being really sensitive, all I have to do is tap it sometimes and it will suddenly disconnect”
“its really annoying sometimes, I pick it up and it clearly has power, but it just disconnected randomly”
“if I open it up and replace the batteries, it works for a few minutes and then it continues to play this unhappy game of mouse playing dead”
I searched the googlepedia, and came up with a whole list of reasons for what could be wrong; I tried everything. A lot of people were blaming Lion for their woes. But in the end a bit of scientific and objective rationalizing came up with the answer.
1) the batteries were fine, they worked in other devices
2) the mouse was fine, it had never been dropped, and it worked ‘most of the time’
How could this be? Well here’s the answer to your puzzle and mine. A flat positive terminal is necessary to keep power to the magic mouse, and having a small point on the positive terminal will result in sudden power failure when the mouse it bumped, tapped, or generally touched in the wrong way.
Energizer Batteries, like Duracell Batteries, have a flat positive terminal.
Eveready Batteries have a small protrusion on their positive terminal.
Save yourself some trouble, and make sure you buy the right batteries next time.
PS. The same can be said for the apple bluetooth keyboard, but it requires a more significant jolt to induce battery movement.