Just wanted to clarify 'apparent CYC Photon overheating problems' so the game of telephone doesn't get out of hand.
While I respect m@Robertson and all the contributions he has made on this site, he has an obvious hatred for CYC due to issues he had with previous products. I understand this, I have the same hatred for the TSDZ2 with OSF due to my experiences (including frequent overheating) and early bearing failure(<1k miles)
Please note that m@Robertson does not have any actual experience with the CYC photon.
Much of the overheating claims seem to come from the "High Voltage DIY Electric Bikes and Vehicles" channel on YouTube. Note that the author of that channel has quite a few high power kits and seems to do a lot of his riding on throttle only. I actually addressed this in the YouTube comments on one of his photon videos and he agreed on being spoiled by his 72V BBSHD kits and that the Photon may not be the best choice for his riding.
This channel also seems to show the DM02 with external ASI controller on 52V doing a claimed speed of 35-40kph going up a 10% grade without overheating. In fact, in that video, the max temp seemed to be around 60C with power levels maxing out around 1500 watts , not sure where that temp sensor is or if it is calibrated correctly by the external ASI controller but that thermal performance seems pretty unrealistic. I know my 52V BBSHD would overheat in those conditions.
For the record, my two 52V DIY mid drives are a BBSHD and CYC Photon (currently at 1300 miles). I ride pretty much everyday and swap bikes for each ride. I weigh about 240#
Of course the BBSHD is a monster buts its cadence based assist is pretty soulless. The CYC photon torque sensing is the best DIY solution I have ever had and in some ways is better than my favorite factory mid drive unit (Brose). I do not run a throttle on the CYC Photon.
I am running my Photon in the highest power preset (RACE, Unrestricted), this appears to be 500W at assist level 1, 1000W at assist level 2 and 1500W at assist level 3. 90% of my riding is at assist level 2 and at this power level, the only overheating I ever saw was on climbs greater than 12% using a 42t front chainring and 11-36 cassette. With a 11-46t cassette, no overheating under the same conditions. I can get overheating (>90C) using assist level 3 when the grade gets above 8% or so and I am going all out (my max capacity). I also can get overheating at speeds above 25mph or so battling headwinds going up 4-6% grades. Otherwise, I rarely see the Photon go above 60C.
I have never experienced overheating in the lower presets.
Many Photon users on endless-sphere also claim a lack of overheating issues.
IMHO, the CYC Photon was designed as a DIY solution to compete with the factory mid-drives, not an all out high power or throttle setup. In that respect I consider it a success.
To bad the price is $$$$