Mikes guide is really awesome, but I have a couple of questions - maybe someone who has tried it can help:
Is the am/pro/DA cranks using the same battery (I would guess so) - have anyone else actually tried taking one of the SRM's with the older design apart?
Is there anything special I have to be concerned about when putting the white disc cover back on? - Does it make a "click" sound or anything similar - It really would be a bummer if the SRM crankset isn't sealed properly when riding in rain!
Now we really only need a guide on changing the Powercontrol battery! I guess the real problem is to get the existing battery off (it's glued in place) - installing the new battery would just be a matter of using a glue gun...
EDIT: I think someone in here (maybe Adam Hansen) mentioned that he sealed the unit with something to make it watertight?
I just took mine apart two weeks ago and it is just a regular pro version. It appeared to be the same as the DA etc... If you install the whit disc on correctly the chanrings will help seal it up better. It is a really simple process and will save you alot of time and some money as well.
ust google the battery model number that is posted above and someone in Europe should have it for under $30. The only bad thing is it must be shipped by ground since it is a lithium battery.