Most Braun shavers use AA or AAA batteries. These are often nipple versions.
My Braun 4000 series Razor uses two AA type Ni-Cd batteries with nipples.
These batteries just pop out once you remove the inner casing. Just undo the two screws in the base hidden behind two black rubber stops that just lift out and remove the shaving foil to reveal the two star screws which need to be removed. You'll need a T7 star screwdriver to do this.
Once these 4 screws are removed, lift off the head casing and then simply put the inner piece out. Very easy.
You'll see two NiCd batteries held in by their nipples by force via metal V-shaped sleeves. A small screwdriver applied to an end will simply get each battery out.
There is a small piece of sticky foam on the back of the batteries to help keep the batteries in place. But not much force is needed to lift them out.
Ni-Cd cells have a memory effect and will become useless after 2 years regardless of how you treat it due to the nature of the chemistry of these old types.
Modern batteries use Ni-MH which will last longer and if you use the latest AA 2000mAH+ types like Maplins Hybrids AA then you'll find they'll keep their charge over night. So you'll get far longer out of them per charge.
Or use normal Ni-MH if you can find these hybrid/Stay charged types.
The old AA Ni-Cd types were typically only 700mAH so you'll get a lot more time between charges.
To replace the batteries with non-nipple types, just get a piece of kitchen foil and fold them over and put on each end to ensure there is a tight fit against the metal sleeves.
If you forget the polarity of the batteries, then look on the black casing as there is a - and + marked on it to remind you. :-)
Have fun.
Stuart Halliday
November 2010