Hi all,
If you own an old Polar V650 bike computer, you may know that its only official sync path is Polar FlowSync, which needs Apple’s Bonjour service and often doesn’t work on Windows 10/11. I built a small open-source app (GPL-3.0) that reads the V650 directly over USB, and it can send your sessions to Intervals.icu.
How the Intervals.icu part works:
• It builds a FIT file from the device’s own data (checked against Polar Flow’s exports: identical session totals, timestamps, positions, distance, speed, altitude and cadence; heart rate 99.5 % identical).
• It uploads it with your API key (Settings > Developer; the key stays on your PC, encrypted by Windows) through POST /api/v1/athlete/{id}/activities, with an identifiable User-Agent.
• Upload is manual (per session or a selection), or automatic for new sessions only if you turn it on. It never sends your history in bulk, and it remembers what was sent.
• Not exported yet: RR intervals and temperature.
Other things it does: exports FIT/GPX, uploads to Komoot, manages routes (device, Komoot, GPX), and builds up-to-date offline OpenStreetMap maps for the device. English/French interface, units follow the device.
Please note: it’s reverse-engineered, tested on a single V650 (firmware 1.5.5) on Windows 11 only, and it writes to the device’s memory, so use it at your own risk. I haven’t tested it side by side with the Polar Flow → Intervals.icu link, so you could get the same session twice if you enable both. Not affiliated with Polar, Komoot, Strava or Intervals.icu. The code was written with the help of Claude (Anthropic); all tests were done on my own device.
Feedback from other V650 owners (other firmware versions, Windows 10) is very welcome.
Thanks for reading, and have a great weekend!