None. It's a cateye CL100 (one of the early cordless) but I did notice latterly in cold weather that going above 20 mph it would not register a speed and dropped to 0. So I changed the sender battery at about 9500 miles (the instructions say change every 10K miles!)

When it reset, I changed the display battery as doing this resets everything again.

I found out that since changing my wheels, the computer was on the wrong setting and I've actually gone further than I thought (and faster)