Testing Accuity V4.1 Bicycle Powermeter
I’ve also made my Garmin Connect file public (Garmin here, Fit File here) so everyone can download it. There are anomalies and this is a first test!
- Bad battery connection means that it loses it’s zero and causes massive offset showing as huge power numbers (up to 18000 watts!)
- A few times during the video it’s noticeable that if the crank hasn’t been rotated in a while and during the first rotation there is an abnormally high power number. There is an overflow issue or double tripping of the Magnetic reed switch causing an erroneously high power for the first 1 – 2 rotations then it stops. I didn’t see this as much in the later part of the ride. I think it’s an ultra low cadence problem.
- The bump issue is related to the magnet position I found out later during the ride. If I hold my legs level with my right leg on the back side it can trip the reed switch multiple times in a very short period with half my weight on it. Obviously a false 200+RPM reading combined with 100NM torque will give over 1000 watt reading. This is solved on SRM and Quarq by putting the magnetic pickup not in line with either crank arm. Smart for them, I missed this in designing.
- Reads back a random value when told to calibrate. Minor but would be useful to implement an actual value. It’s standard with Quarq and SRM.
- Have to calibrate twice – once for each side. Not really needed but it’s left as a debug measure. It could be useful to know the offset of each side as the ANT+ protocol only supports one value.
- Sorry it’s hard to see the actual values in the video.
Some more pictures
