So I changed the battery in my Cannondale Si SRM this weekend. Of course I ordered the battery referenced above only to find out when I cracked the SRM open that it was the wrong battery. For the Si SRM the battery is a rectangular one (as shown below) & not the round one used in the Dura-Ace SRM.
So, just a little cautionary tale...
I have an older SRM Cannondale SI. Guess what? It uses a round battery. I guess the moral of the story is that if you have an older SRM, you should probably crack it open quickly just to make sure what battery is in there. The spider is machined for the battery type, so there's no mixing/matching.
Now for the good news: My SRM had the round battery, but didn't come with the lithium cell shown on page one of this thread; it had 2 CR2430 batteries welded together and wrapped, with solder tabs welded to the battery. Keep in mind this is the battery that came in the SRM new. The battery lasted about 500 hours of use, and was also sitting unused in a garage for about 4 years--so I'd say the battery life was pretty reasonable.
The nice thing about this is that if you're in a pinch (as I was when the battery died) you can find these batteries pretty much anywhere. I don't know where to find the battery solder tabs, but I went to one of those local "battery stores", and they, welded the 2 cells together, wrapped them welded the solder tabs, $9.00 out the door. I got it done at this place: http://www.batterydepot.com/?gclid=CPSO ... gwodvm9KIw
These batteries are much more readily available, so maybe this will help someone else who's in a pinch looking for an SRM battery. I did the surgery and it's working great.