Originally Posted by gadabout007

A extremely cheap friend of mine bought the powercal and has been telling me for the last month how great it is and how I've wasted so much money on my two powertaps.

I borrowed the strap for the weekend so yesterday I did my Saturday workout with the powercal on my garmin 500 and the powertap on the my joule.

Powertap 58 minute workout

Average Power 217
Peak Power 941
5 Second 793
1 Minute 322
5 Minutes 278
20 Minutes 239

Powercal 58 minute workout

Average Power 231
Peak Power 1148
5 Second 974
1 Minute 397
5 Minutes 302
20 Minutes 263

My best recorded 20 minute threshold test was 244W in June of this year. My last test two weeks ago was 236W and it almost killed me hitting that number. If every possible variable was in my favor, there's still no way I could sustain 263W for 20 minutes. My best recorded PPO is 1326W which was oddly a one off and I haven't hit close to that number since. The 941W the the powertap recorded was when I sprinted through a yellow light and can guarantee that I didn't go over 1000W even for a second.

There were several times that I noticed that it was reporting power when I was coasting/recovering between intervals. It's a neat toy but the data collected is totally inaccurate and therefore useless for a serious training program or gauging your progress.