I have used the single sided P1 pedals for a few years with no issues. I recently replaced the battery. The pedals are usually on my trainer, but I took them off to use outside for a few weeks, then put them back on the trainer bike. The power numbers are now way off. I would guess about 25-30% too low. Usually I am able to ride 3x10 comfortably at 250 watts. Yesterday I could barely manage 200 watts. I also tried to do a 3 minute interval as hard as I could, and again the numbers were way too low. Any suggestions on how to fix this?

I did some research and figured that maybe the crank length is not set correctly. The default is 172.5 and my bike has 175mm cranks. I use a Wahoo Elemnt. I tried to go on the Wahoo App and set the correct crank length, but can't figure out how to do that either.