CYC PHOTON

OK, this is not good. I went for a ride today in 75F degree weather, and by the end of my ride the Photon was throttling heavily, sometimes as far down as zero watts. Battery was 56V, so not battery related. The motor began throttling itself at just 50C motor core temperature. Motor temperatures only reached the 70s.

Thought this thing was designed to hit 100C without issue? This thing was just crapping out on a mild day.

I'm going to go take it out again for a ride and figure out what's happening. I might need limit the motor to 750W. I think over the course of the ride, the motor became heat-soaked and couldn't shed the heat and cool down. The motor casing at the end of ride was only 44C degrees. Really can't make sense of it because the temps didn't look bad to me.
 
Sorry for the troubles, @nervagon - I've not seen that behavior from my motors, which I've run up to an indicated 200+F.

I'm speculating that perhaps the motor core temp sensor is failing, or perhaps the related spring loaded contact pins are not making good connections.

By chance, did you notice what the controller temps were?
 
Mongo said:
Sorry for the troubles, @nervagon - I've not seen that behavior from my motors, which I've run up to an indicated 200+F.

I'm speculating that perhaps the motor core temp sensor is failing, or perhaps the related spring loaded contact pins are not making good connections.

By chance, did you notice what the controller temps were?
Click to expand...

Controller temps were considerably below the motor temps.

It ran fine on my second ride, so I'm just going to do a factory reset and hope for the best. I might join a long group ride on Tues. I'll report back if the issue returns. Another weird thing is the motor sounded better on the second ride too. Hopefully just software gremlins that a reset can fix.
 
nervagon said:
Controller temps were considerably below the motor temps.

It ran fine on my second ride, so I'm just going to do a factory reset and hope for the best. I might join a long group ride on Tues. I'll report back if the issue returns. Another weird thing is the motor sounded better on the second ride too. Hopefully just software gremlins that a reset can fix.
Click to expand...
There was a recent firmware update, do you have it?
 
My experience regarding thermal throttling:
When operating only pedal-assist, it is hard to each throttling at all. Even at the highest support setting I am using for eMTB off-road riding I always stay below 70C, maybe 80C in a very steep climb.
Only when involving throttle, I observe the thermal limiting.
I think it starts at 80-85C (underneath I observe the full 2000W are available), and above max power is reduced more and more, until I see at 99C only 500-600W being available.
 
I would say the Photon throttle can be modulated quite well. When I was injured at one feet, I could drive on my EMTB next to my wife walking, and keep the slow speed with the throttle.
 
The CYC Ride Control application (Android and iOS) allow calming down the throttle ramp-up and max power - to a degree. It's not a flexible as Luna's V2 app IMHO, but it does help:

1714684463955.png1714684683281.png
There are also some tweaks that can be made to the BBS02, via the stock and open source firmware & configuration tool, though I got the impression that satisfaction is mixed.
 
Last edited:
SammySamm said:
Halloechen Tom.
Can you oparate the Photon throttle smooth in a wide range, or is it like BBS02 jerky and almost an on–off switch?
Click to expand...
I find mine to be smooth but over a very small initial range, after that it doesn't vary so much and is pretty much full on. It works fine, though - on mine I usually roll my thumb against it, rather than pulling on the blade directly.

I don't ride much with throttle partially used, tend to use it for a real boost for short steep sections and the like.
 
hindesite said:
tend to use it for a real boost for short steep sections and the like.
Click to expand...

The jerky BBS02 twistgrip on my vintage Mountain Cycle San Andreas SR doesent work sensitively. It´s fine for a thrilling motocross-style climbing.

2.jpg

But in order to climb a steep rocky trail in slow trial-mode, a well metered „throttle-push“ is needed.
I hope my Photon will do well in the new build.
 
SammySamm said:
The jerky BBS02 twistgrip on my vintage Mountain Cycle San Andreas SR doesent work sensitively. It´s fine for a thrilling motocross-style climbing.

View attachment 352179

But in order to climb a steep rocky trail in slow trial-mode, a well metered „throttle-push“ is needed.
I hope my Photon will do well in the new build.
Click to expand...
Weren't there rare reports about open source firmware improvements regarding to throttle smoothness on BBS02? Seems like there isn't any snapping sound coming from freehub and it's easier to accelerate very gently according to personal experience with BBSHD using open source firmware.
 
OK, just got back from a ride in 75F weather with long steep climbs. Motor temp hit 89.9C and stayed there a long while! At that point the power was jumping between 350w and 450w. It is only 75F degrees outside. My last ride where the motor did OK was an evening ride with cooler weather.

There is no way this motor will perform in the summer once things heat up.

The Photon is coming off the bike. I guess my quest for the perfect mid drive continues.
 
neptronix said:
Damn, that's worse than i thought it would be.
Click to expand...

Ive been through 2 motors now in short order. I just can't seem to find a proper modern successor to the BBSHD. Something lighter with torque sensing, but still as dependable.

Here's where I think my problem is with the Photon. I don't have it restricted, so at the beginning of the climb it will put down 1000+ watts, but then the temps skyrocket, and it just doesn't have the ability to cool back down. That first little boost at the beginning just wrecked the whole rest of your climb. Even when the motor was not stressed, the motor temp was between 54C to 64C. In my opinion, the skeptics where right... this motor cannot shed heat. I think limiting it to 500W max might help prevent the runaway heat build that will ruin the rest of your ride.
 
CYC really pulled one over on people with this motor if it's running 64C at rated power in slightly above laboratory 'ambient' temperatures. 64C at medium load tells me we have an inefficient stator and adding volts to the motor will likely not improve the situation as it did with the BBSHD.

I think it would be reasonable to limit it to 750w. Removing the controller from the case may help the heat situation too.
 
neptronix said:
CYC really pulled one over on people with this motor if it's running 64C at rated power in slightly above laboratory 'ambient' temperatures. 64C at medium load tells me we have an inefficient stator and adding volts to the motor will likely not improve the situation as it did with the BBSHD.

I think it would be reasonable to limit it to 750w. Removing the controller from the case may help the heat situation too.
Click to expand...

This motor will melt in 90F weather. And I think it's OK to limit the Photon to 750W in SoCal winter, but the limit for summer will probably need to be 500W.
 
I went back and checked my route where the motor hit 90C. It was about a 1 mile climb at roughly 10% grade. Something my BBSHD could do without issue, even on very hot days.
 
nervagon said:
This motor will melt in 90F weather. And I think it's OK to limit the Photon to 750W in SoCal winter, but the limit for summer will probably need to be 500W.
Click to expand...

You can take maybe 100w of heat out by removing the controller or using an external controller.

nervagon said:
I went back and checked my route where the motor hit 90C. It was about a 1 mile climb at roughly 10% grade. Something my BBSHD could do without issue, even on very hot days.
Click to expand...

Hmm the mid-drive oldtimers say you should keep the cadence of the motor as high as possible by keeping up the RPM. This is an old trick for the BBS02, which had maybe 80% efficiency and a quite small stator, which seems similar to this Photon in terms of actual power handling.

Do you keep to a good cadence ( ~80-90rpm ) while hill climbing?
 
neptronix said:
Hmm the mid-drive oldtimers say you should keep the cadence of the motor as high as possible by keeping up the RPM. This is an old trick for the BBS02, which had maybe 80% efficiency and a quite small stator, which seems similar to this Photon in terms of actual power handling.

Do you keep to a good cadence ( ~80-90rpm ) while hill climbing?
Click to expand...

42t chainring, 50t low gear. As low as i can go. Cadence around 90. Speed 8mph.
 
That's basically the same condition ( and rider weight) where i smelled my motor varnish for a minute on a bbs02, pedaling as fast as possible too.

Sorry to hear it!
 
nervagon said:
Ive been through 2 motors now in short order. I just can't seem to find a proper modern successor to the BBSHD. Something lighter with torque sensing, but still as dependable.

Here's where I think my problem is with the Photon. I don't have it restricted, so at the beginning of the climb it will put down 1000+ watts, but then the temps skyrocket, and it just doesn't have the ability to cool back down. That first little boost at the beginning just wrecked the whole rest of your climb. Even when the motor was not stressed, the motor temp was between 54C to 64C. In my opinion, the skeptics where right... this motor cannot shed heat. I think limiting it to 500W max might help prevent the runaway heat build that will ruin the rest of your ride.
Click to expand...
Maybe the new bafang 635?
 
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