mschwett 

i've been using this PM for around a year, no problems at all. pretty consistent data.

this AM i went to zero the PM (as i do before all rides, using the 4iiii app) but it wouldn't zero. so i just rode - the weather was about the same anyway - but noticed immediately that the value was jumping around a lot more than usual.

here's the same short climbing segment at the same scale, more or less, from a ride a few days ago vs today. the top blue line (today's ride power) is very obviously spikier. the average data looks pretty close to what i'd expect, maybe a tad low. before i reach out to 4iiii, any suggestions here? batteries are both fairly new and the only thing i can think of is that i cleaned the bike....

scottfsmith

I’d change the batteries one more time and try to zero. If it fails again I would contact 4iiii. I had an issue with my power meter failing and it was because the “new” batteries turned out to be really cheap ones which had almost no lifespan. No more cheap 4042 cells for me any more..

mschwett 

thanks. probably a good idea. i just took them both out and cleaned the contacts and put back in, and it zeroed. will see if it’s spiky. i did notice a tiny hairline crack in the cover for the drive side, which i think is a sort-of-known issue. will get a replacement before it gets big enough to let some water in.

edit: did a quick ride home, very smooth data. glad it's fixed (for now) but not very confidence inspiring!