www.powertap.com They make quality products. I own two hub-based power meters from Power Tap and they've given me reliable performance/service for over 10 yrs.
So, what was my initial impression of the PowerCal HR/Power Monitor? I like it. It does exactly what it was advertised to do and that is use it's internal algorithm to give an estimate/approximation of the power output of your ride based on your HRmax. Check out one of my earlier blogs/posts on the PowerCal. Watch the short video given by Dr. Allen Lim (a world recognized expert in power meters).
Last nights ride was not your typical ride. It was cold (45F), rainy, muddy & wet- not to mention "dark". I rode on my Mountain Bike and I had a waterproof jacket, winter riding pants, gloves, hat, etc. I was pretty much all bundled up. Not really the best attire for producing maximum watts on the bike. Besides, I wasn't really fresh or in "form". I was still feeling the effects of an earlier workout in the week. I'm still trying to get back in cycling shape. I've only been riding since July of 2017 after a couple year layoff.
I included the graph above to show the Garmin Edge output from the PowerCal. It says my HRavg for the ride was 146 bpm, Avg Speed of 12.5 mph and Avg Power of 190w. You can see why the average speed is only 12.5 mph when it looks like the majority of my ride was above the 15 mph line. That's because there are a lot of times where I had to slow down to say 5-8 mph during road crossings, bridge crossings, deer crossing, etc. Those times/speeds are used in the average calculation. If I had to guess, I'd say my "real" average power output riding at 16 mph was about 190-200 watts. PowerCal reported over 200watts, more like 220watts. That's not too far off. What I'll do this weekend (or next week) is use the PowerCal HR monitor on my Computrainer and compare the outputs during a steady state ride. That will truly tell me what the delta is between the two. I'll use my Garmin Edge to capture the PowerCal HR and estimated power and I'll use my Computrainer to capture the "true/actual" power.
Until then, Power ON! Coach Rob