I think this thread already answered my question but...

I have a 2 1/2 year old Garmin 305, w/ HRM and cadence sensor. However, the battery is rapidly losing its ability to hold a charge. So to confirm- if I get the Edge 500 w/o new accessories, I could use the old 305 accessories, right?

As far as I can tell, the battery in the 305 is not intended to be replaceable (although there does seem to be a way to do it if you're more electronically talented than I am). I would be happy to find a way to extend the life of the 305 rather than spend the $$ for a new device.

Any thoughts on this?