CYC PHOTON

Thanks!. I should have mentioned that I need 152mm long crank arms. Unfortunetly the shorter Bafang arms do not have the same offset as the 170's do so the Q is increased, more so on the right side..
 
I won't quibble with too much of this but wonder why and how you spend so much time and so many words on a motor clearly not designed to do what you want... again not knowing if you and your bike are heavy and/or if you can pedal. The Photon handles mid 90s temps here on rolling rides with 2,500 feet of climbing in 30 miles at full pace with me doing my share, of course. No idea of the average watts, but certainly not near full power, except on the rolling climbs. But, no, I am not taking it to Park Central road that climbs 2.5 miles straight and tops out at 17%. It could probably do it but certainly not at full pace/power.

Maybe try the Bafang M635 with torque sensor and report back your findings. It would be nice to see how one of these handles your torture testing. If it's good, I'd probably get one for one of my bikes.

nervagon said:
So temps are hitting the 90s already in San Gabriel Valley at the beginning of summer. The Photon was not a good choice. It simply cannot handle this heat. At this rate we will be in the hundreds soon.

I will be able to do the 10% grade hot weather test for potential Photon buyers, but my honest feedback will be met with more accusations that I am doing it wrong, not pedaling at a high enough cadence, or have a defective unit… or that long 10% climbs are outside of the scope of intended use for this product.

In 75F degrees, and limited to 700W, the photon down-throttled to just under 500W when climbing. In 90F+ degrees, the motor will probably need to be limited to about 450W, being optimistic. At that point, it is easily outshined by a cheap ToSeven DM02.

My solution for keeping the Photon happy… adding a Bikee Lightest motor to the drive train likely won’t be permanent. I am dropping the chain off-road. That is not the fault of the photon, or the Bikee… it’s the result of me not figuring out how to fit the needed lower chainring tensioner to ensure enough chain wrap with the Bikee and the photon jumbled together. It was an interesting experiment, and revealed some interesting things.

For instance, I ended up loving 300W from each motor for a combined 600W with high combined torque. So a dependable 750W nominal mid drive with high torque would keep me happy in any situation.

As I mentioned before, the thing I hate the most about the Photon is how the thermal regulation bounces the power level all over the place while you are trying to maintain a consistent cadence up a long climb. It is the worst mid drive riding experience ever under those conditions, and honestly just shitty engineering.

I wish I had access to a Brose mid drive bike to compare against the Photon in real world stress. From what I’ve read, the Brose drives are very quiet, and have good torque. I hate the noise that the Bosch performance line motors make, so I would never be happy shelling out for a Bosch drive train bike.

Right now, the specialized Vado and Ride1up prodigy 2 are affordable class 3 Brose drivetrain hard tails with front suspension that can be set up as capable gravel/commuters and I wonder how they would feel compared to the photon in the real world. But I would have difficulty pulling the trigger on a proprietary ebike that has no repair ability.

So yeah, I am torn. I like tinkering on my bikes myself, hate the douchebags at local bike shops, but I feel like the DIY ebike parts scene already peaked and is in either stagnation or full blown decline.

What was the peak? The BBSHD its prime. Companies like Lekkie were designing premium parts for it, and innovative batteries like the potted and individually fused and wireless Luna Wolfpack made the DIY scene vibrant and poised to outshine premium big brand factory ebikes.

Then Bafang turned its back on the DIY scene, Luna discontinued the Wolf Pack and shifted to pushing surrons, and Lekkie never supported another DIY motor again. The promise of Americans converting millions of existing bikes to premium ebikes was now a pipe dream. Destined to remain a fringe hobby. One of the hurdles: Americans are lazy, lack creativity, and basic mechanical skills. It’s the same reason consumer 3D printers failed.

And now that we have ebike prices jumping by up to 25% due to the long-paused tariffs on Chinese ebike components being reactivated… DIY could soar once again if production of modular drive train components shifted to North America. But that won’t happen… because the future isn’t the Jetsons, or Star Trek, etc… it’s dystopian… the enshittification of every promising technology.

Back to the word modular. The electric drive train on bicycles should be modular just like the rest of the components on the bike. We need to ditch the welded-on bottom bracket entirely in favor of an open source 3 bolt pattern that will allow any motor or bottom bracket to be attached to the bike frame. This is so obvious that it really is disappointing that it never came to be.

And back to the tariffs… they aren't new. They were simply paused. And yet all these companies are acting like they were blindsided by this. They were given ample time to prepare, but capitalism only cares about next quarter’s report. The long game isn’t compatible with the wall street casino. And the Wall Street casino shits the bed any time interest rates go above zero.

Damn, that turned into a wondering rant.
Click to expand...
 
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It would be nice to get the Cycmotor offerings, including the Photon, into the motor simulator database at Motor Simulator - Tools . Ditto for the BikeOn, Lightest and Add-e Next motors. The simulator does include a thermal simulation, of course I don't know how accurate it is. I ran the Rt.39/San Gabriel canyon for a Bafang BBS02 (6% grade, 16 miles, see Climbing Hwy 39 - Crystal Lake, CA by bike - cycling data and info), and it can do it real fast, like 20 mph. Of course it will also empty a big battery real fast.
 
raylo32 said:
I won't quibble with too much of this but wonder why and how you spend so much time and so many words on a motor clearly not designed to do what you want... again not knowing if you and your bike are heavy and/or if you can pedal. The Photon handles mid 90s temps here on rolling rides with 2,500 feet of climbing in 30 miles at full pace with me doing my share, of course. No idea of the average watts, but certainly not near full power, except on the rolling climbs. But, no, I am not taking it to Park Central road that climbs 2 miles straight and tops out at 17%. It could probably do it but certainly not at full pace/power.

Maybe try the Bafang M635 with torque sensor and report back your findings. It would be nice to see how one of these handles your torture testing. If it's good, I'd probably get one for one of my bikes.
Click to expand...

I spent $1k on the photon. I’m pretty sure this thread is an appropriate place to discuss this motor. I think you’ll find longer Amazon reviews on toothpaste. If you don’t find any value in my thoughts on the photons, you are free to ignore them. Why do I care so much about a thousand dollar purchase? What a silly question. Why do any of us sit around discussing DIY ebike motors? We are all weirdos. I'm so weird that I went to a 3-day boot camp on converting petrol cars to BEV.

Conversions... taking beautiful bikes and cars and electrifying them is very interesting to me. The Photon came the closest to a mainstream-ready experience, but it simply fell short due to poor decisions in the design and engineering process, and especially at the price. The only hope for me might be the delayed Proton, and my thoughts on the other options are below.

The bafang M635:
Are 52V batteries compatible? Bafang says 48V only, display supports up to 60V. There is a bafang app. What parameters can you change? Seems like basically nothing can be configured. Bafang is still tweaking the firmware. M635 shipped to vendors with garbage torque sensing. If I buy one, how will I update the firmware? Why did they ditch the torque arm compatibility in favor of a weird loop you are supposed to put a zip tie or pipe clamp through? It looks silly. Still square taper in 2024. Of the few vendors selling this motor, they offer no valuable info their listings. Bafang doesn’t care about the motor, their vendors don’t care about the motor, and the aftermarket doesn’t care about the motor.

www.johnnynerdout.com

M635 Bafang Mid Drive- Torque Sensing | Johnny Nerd Out

Standing on the shoulders of the M625 motor, this system adds Torque sensing and the ability to use non-proprietary batteries (aftermarket batteries can be used!)This is a brand new kit so accessories and options are still limited :(Please note that motor kit does not allow for making any...
www.johnnynerdout.com www.johnnynerdout.com
This is a brand new kit so accessories and options are still limited :(
Please note that motor kit does not allow for making any changes to the motor performance like the other aftermarket kits. The speed is locked at 28mph and the wheel size will need to be set here at the warehouse before shipping, so please leave us a note as to what size you would like it to be set at.
Click to expand...
WTF? The M635 is so locked down that you can't even change the wheel size? Only the dealer can do that? This motor is more locked down than a Bosch. Even Bosch lets the end user change parameters such as wheel size. That is a basic setting. M635 is DOA.

This is the (only?) M635 display:

零部件

Bafang description
bafang-e.com bafang-e.com
Nominal Voltage (Vdc) 36 - 60
Click to expand...
It looks like maybe my existing 52V batteries would work? Still unsure due to canbus shenanigans and mystery firmware.

The ToSeven DM01:
The 42T chainring has 4mm less offset, so it would screw up my chain line. That is a 54mm chainline on a 68mm BB and 135mm OLD cassette! It seems the reduction housing must be massive to explain this. Also the chainring IS NOT narrow-wide.

54mm happens to be the exact chainline of a Rohloff IGH. So a Rohloff would make the DM01 possible because it solves the poor chainline, and it solves the lack of narrow-wide chainring. The chain can be much tighter with an IGH, so chain drops are less likely. DM02 has a wide Q-factor, but closer to symmetrical than its little brother. Max speed is 160rpm. Does this drive have the same problems as the BBSHD... in that it wants to spin too fast for human input? New company with no reputation.

The DM01 sounds a little bit louder than the BBSHD. More high-pitched and grindy:
... but nowhere near as bad as Bikee Lightest, Bosch, CYC stealth, etc.

The DM01 is an option for my current bike build if I purchased it along-side a Rohloff.

The DM02: very wide, and very asymmetric Q-factor for a 500W drive. I am fine with wide-Q, but not fine with asymmetry. The chainring IS NOT narrow-wide. Spec-wise, the DM02 on paper is similar to a modern Bosch or Brose in torque and power. 90Nm torque, 500W. DM02 stock controller "must not be programmed above 15 amps or the controller may be damaged." Peak of 780W at 52V. Peak of 540W at 36V. Bosch and Brose peak around 600W at 36V. Bosch and Brose are designed for comfortable pedaling cadence, not sure what the power curve is on the toseven motors. Assuming that since DM02 is rated 500W max (36Vx15A), the most natural cadence will be at 36V. Max speed is listed at 100 RPM (similar to Bosch and Brose). New company with no reputation.

The DM02 sounds HORRIBLE in this vid:
High-pitched and grindy. Yuck!

Tongsheng:
Reputation of overheating and lack of durability. They made a new motor (TSDZ8), but nobody cares, and there is little info on it.

Bikee:
Very loud. Very conspicuos looking on the bike frame. Looks more illegal and almost as loud as motors like CYC Pro and Stealth. You don't want to draw attention to yourself in the first place, and you don't want to sound like a surron. DTLA is such a dystopian hell hole right now that illegal bikes roam freely, but the more chill SoCal communites are sick of the surrons and douchbags that are attracted to those bikes in higher numbers than the class 1,2,3 bicycles. It's best to be stealth now. And that is quiet with a low visual profile.



BBSHD:
Dependable, powerful monster. Huge aftermarket. Very easy to get parts. Open source firmware option. Virtually silent. No torque sensing, only old-school cadence. Tendency to out-spin the rider. Not a good choice for fitness. Large and heavy... the price you pay for dependability.
 
 
Oh, this definitely the place to discuss Photon, but I knew your opinion about it about 15 pages and 3 months ago and nothing has changed in the postings here on the last page. I agree, you guys are weird! IMO, you just need to get out and ride your bikes more and not overthink it all. After all, that's what this is all about, right? Otherwise go to work for a company... or yourself... and develop this magic motor that can drive up 10% grades at 25MPH all day in 95 degree ambient, with a torque sensor, and can be sold for $300.

nervagon said:
I spent $1k on the photon. I’m pretty sure this thread is an appropriate place to discuss this motor. I think you’ll find longer Amazon reviews on toothpaste. If you don’t find any value in my thoughts on the photons, you are free to ignore them. Why do I care so much about a thousand dollar purchase? What a silly question. Why do any of us sit around discussing DIY ebike motors? We are all weirdos. I'm so weird that I went to a 3-day boot camp on converting petrol cars to BEV.
Click to expand...
 
rocketman58 said:
PS: I need 152mm cranks so this is another problem.
Click to expand...
Not really - though it is an additional expense. Maybe suggest CYC add 155mm cranks to their range.

I thought Q factor would be a problem, but (for me) it really isn't. I would not want it to be any bigger though.

endless-sphere.com

CYC PHOTON

Left ISIS Crank Continually Working Loose/150mm Cranks I (and I believe, several others) have experienced the CYC supplied left crank randomly working loose. This is even with using thread locking compound on the fixing screw and regularly checking tightness. The problem is that if it works...
endless-sphere.com endless-sphere.com
 
raylo32 said:
Oh, this definitely the place to discuss Photon, but I knew your opinion about it about 15 pages and 3 months ago and nothing has changed in the postings here on the last page. I agree, you guys are weird! IMO, you just need to get out and ride your bikes more and not overthink it all. After all, that's what this is all about, right? Otherwise go to work for a company... or yourself... and develop this magic motor that can drive up 10% grades at 25MPH all day in 95 degree ambient, with a torque sensor, and can be sold for $300.
Click to expand...

It sounds to me like you are the one that is burned out on this forum, and discussions of motors, and you need to take your own advice and go touch grass and take a break.
 
And speaking of pedal cadence/RPM... does anyone know the Kv value of the Photon? It seems it was designed to spin at all the way up to 300rpm at the crank, and I am now wondering if on top of poor thermal design, the motor is also poorly matched to human cadence. The BBSHD has a max RPM of 160, so as soon as I saw the photon is 300rpm at the crank, I did a double-take.

Now we might be able to assume that the 300rpm is with the max supported 52v battery. That seems like a safe assumption. So if I dropped down to a 36v volt battery with the photon, the max RPM at the crank would be closer to 200. And typically with an IPM, the most efficient point would be around half of that... so we are looking at the motor spinning most efficiently at around 100rpm at the crank with 36V. Now we are more closely matched to a human rider.

But at 52V, if the motor draws 10A to produce 520W, dropping the voltage to 36V to produce the same 520W would require 14.4A. Dropping to 36V to get better cadence would also pretty much double the heat... something the Photon doesn't like. So we would need to also drop the wattage. So 36V x 10A = 360W.

36V and 360W is a Photon configuration that is closer to matching human cadence and should be an efficiency sweet spot for the motor when riding in PAS. I am making some assumptions here, but CYC's claim that 700W is the most efficient seems even more dubious, unless they mean throttle on flat ground.

Conclusion:
I might need to test the Photon with a 36V pack.
 
LOL... maybe a little. But I Iike to see people's builds and discuss riding. But I certainly am tired of hearing about whatever it is you large non-pedalers are doing with it and how it can't do the impossible. Easy enough for us to mutually ignore... Done on my end.

nervagon said:
It sounds to me like you are the one that is burned out on this forum, and discussions of motors, and you need to take your own advice and go touch grass and take a break.
Click to expand...
 
Last edited:
nervagon said:
The Photon came the closest to a mainstream-ready experience, but it simply fell short due to poor decisions in the design and engineering process
Click to expand...
I very strongly disagree. Just because you don't like the decisions they made doesn't mean they were poor decisions.

If you read what CYC have published about their intended aims for this motor, you would see that they have done an exemplary job of hitting those probably 95%.

It also happens that for some installations there is no reasonable alternative. From my perspective, they nailed this 100% when nobody else was even close.

And it pays to remember that the designers of the Photon (and all the alternatives) are people, too. I always try to discuss the product as if the designers were in the room. Because they very possibly are.
 
hindesite said:
I agree. It would have been far more helpful to know the most efficient cadence.
Click to expand...
Educated guess:

52V: 180 RPM to 240 RPM cadence
48V: 166 RPM to 222 RPM cadence
36V: 124 RPM to 165 RPM cadence

Good luck with any of those, but 36V would be the only chance most riders could get close to.

This is based on the assumption the the most efficient RPM range is 60% to 80% of max RPM. Doesn't look good compared to drives from Bosch and Brose that are designed as PAS motors.
 
nervagon said:
And speaking of pedal cadence/RPM... does anyone know the Kv value of the Photon? It seems it was designed to spin at all the way up to 300rpm at the crank, and I am now wondering if on top of poor thermal design, the motor is also poorly matched to human cadence. The BBSHD has a max RPM of 160, so as soon as I saw the photon is 300rpm at the crank, I did a double-take.
Click to expand...
Did anyone ever confirm 300 rpm? Seems really high to me. I seem to remember reading that number in the thread before people had even gotten the photon. I also see 190rpm max when I google photon max rpm, though that forum post also says preliminary specs. I'd suggest doing the calculations with an actual motor in hand to get a conclusive number before spending money on a 36v battery. Maybe I'll do it later tonight if I get a chance. Anybody happen to have a conclusive number for the internal gear ratio? Would make the calculations easier.
 
Epithemeus said:
Anybody happen to have a conclusive number for the internal gear ratio
Click to expand...
15.1:1 approximately.

Rikus' video states the rotor generates 7Nm for 110Nm output.

There must be teardown photos somewhere by now with the gears visible, and there may be forum members who can give the exact ratio.
 
Epithemeus said:
Did anyone ever confirm 300 rpm? Seems really high to me. I seem to remember reading that number in the thread before people had even gotten the photon. I also see 190rpm max when I google photon max rpm, though that forum post also says preliminary specs. I'd suggest doing the calculations with an actual motor in hand to get a conclusive number before spending money on a 36v battery. Maybe I'll do it later tonight if I get a chance. Anybody happen to have a conclusive number for the internal gear ratio? Would make the calculations easier.
Click to expand...
Both the product page and the current manual list crank RPM at 300.

I found that old preliminary spec sheet that claimed 190, but for whatever reason it changed in the final shipping product.
 
nervagon said:
I spent $1k on the photon. I’m pretty sure this thread is an appropriate place to discuss this motor. I think you’ll find longer Amazon reviews on toothpaste. If you don’t find any value in my thoughts on the photons, you are free to ignore them. Why do I care so much about a thousand dollar purchase? What a silly question. Why do any of us sit around discussing DIY ebike motors? We are all weirdos. I'm so weird that I went to a 3-day boot camp on converting petrol cars to BEV.

Conversions... taking beautiful bikes and cars and electrifying them is very interesting to me. The Photon came the closest to a mainstream-ready experience, but it simply fell short due to poor decisions in the design and engineering process, and especially at the price. The only hope for me might be the delayed Proton, and my thoughts on the other options are below.

The bafang M635:
Are 52V batteries compatible? Bafang says 48V only, display supports up to 60V. There is a bafang app. What parameters can you change? Seems like basically nothing can be configured. Bafang is still tweaking the firmware. M635 shipped to vendors with garbage torque sensing. If I buy one, how will I update the firmware? Why did they ditch the torque arm compatibility in favor of a weird loop you are supposed to put a zip tie or pipe clamp through? It looks silly. Still square taper in 2024. Of the few vendors selling this motor, they offer no valuable info their listings. Bafang doesn’t care about the motor, their vendors don’t care about the motor, and the aftermarket doesn’t care about the motor.

www.johnnynerdout.com

M635 Bafang Mid Drive- Torque Sensing | Johnny Nerd Out

Standing on the shoulders of the M625 motor, this system adds Torque sensing and the ability to use non-proprietary batteries (aftermarket batteries can be used!)This is a brand new kit so accessories and options are still limited :(Please note that motor kit does not allow for making any...
www.johnnynerdout.com www.johnnynerdout.com

WTF? The M635 is so locked down that you can't even change the wheel size? Only the dealer can do that? This motor is more locked down than a Bosch. Even Bosch lets the end user change parameters such as wheel size. That is a basic setting. M635 is DOA.

This is the (only?) M635 display:

零部件

Bafang description
bafang-e.com bafang-e.com

It looks like maybe my existing 52V batteries would work? Still unsure due to canbus shenanigans and mystery firmware.

The ToSeven DM01:
The 42T chainring has 4mm less offset, so it would screw up my chain line. That is a 54mm chainline on a 68mm BB and 135mm OLD cassette! It seems the reduction housing must be massive to explain this. Also the chainring IS NOT narrow-wide.

54mm happens to be the exact chainline of a Rohloff IGH. So a Rohloff would make the DM01 possible because it solves the poor chainline, and it solves the lack of narrow-wide chainring. The chain can be much tighter with an IGH, so chain drops are less likely. DM02 has a wide Q-factor, but closer to symmetrical than its little brother. Max speed is 160rpm. Does this drive have the same problems as the BBSHD... in that it wants to spin too fast for human input? New company with no reputation.

The DM01 sounds a little bit louder than the BBSHD. More high-pitched and grindy:
... but nowhere near as bad as Bikee Lightest, Bosch, CYC stealth, etc.

The DM01 is an option for my current bike build if I purchased it along-side a Rohloff.

The DM02: very wide, and very asymmetric Q-factor for a 500W drive. I am fine with wide-Q, but not fine with asymmetry. The chainring IS NOT narrow-wide. Spec-wise, the DM02 on paper is similar to a modern Bosch or Brose in torque and power. 90Nm torque, 500W. DM02 stock controller "must not be programmed above 15 amps or the controller may be damaged." Peak of 780W at 52V. Peak of 540W at 36V. Bosch and Brose peak around 600W at 36V. Bosch and Brose are designed for comfortable pedaling cadence, not sure what the power curve is on the toseven motors. Assuming that since DM02 is rated 500W max (36Vx15A), the most natural cadence will be at 36V. Max speed is listed at 100 RPM (similar to Bosch and Brose). New company with no reputation.

The DM02 sounds HORRIBLE in this vid:
High-pitched and grindy. Yuck!

Tongsheng:
Reputation of overheating and lack of durability. They made a new motor (TSDZ8), but nobody cares, and there is little info on it.

Bikee:
Very loud. Very conspicuos looking on the bike frame. Looks more illegal and almost as loud as motors like CYC Pro and Stealth. You don't want to draw attention to yourself in the first place, and you don't want to sound like a surron. DTLA is such a dystopian hell hole right now that illegal bikes roam freely, but the more chill SoCal communites are sick of the surrons and douchbags that are attracted to those bikes in higher numbers than the class 1,2,3 bicycles. It's best to be stealth now. And that is quiet with a low visual profile.



BBSHD:
Dependable, powerful monster. Huge aftermarket. Very easy to get parts. Open source firmware option. Virtually silent. No torque sensing, only old-school cadence. Tendency to out-spin the rider. Not a good choice for fitness. Large and heavy... the price you pay for dependability.
Click to expand...

nervagon said:
I appreciate your candid musings on both the photon and the bikee. I put this spreadsheet together as a way of tracking mid drive developments. I imagine a good combo might be something like the revel propulsion mid drive coupled with a DD hub drive.
Click to expand...
 
nervagon said:
Both the product page and the current manual list crank RPM at 300.

I found that old preliminary spec sheet that claimed 190, but for whatever reason it changed in the final shipping product.
Click to expand...
Actually, it is worse than that, it says >300rpm. Which sucks for pedaling (where we'll never get decent efficiency) but it does mean there is a heap of headroom for throttle users. I've had mine over 60kph, but can't realistically pedal over 45kph (34T chainring, 27.5" wheels).

Please CYC - publish those curves! (or anyone else who has dyno'd this motor).
 
hindesite said:
Actually, it is worse than that, it says >300rpm. Which sucks for pedaling (where we'll never get decent efficiency) but it does mean there is a heap of headroom for throttle users. I've had mine over 60kph, but can't realistically pedal over 45kph (34T chainring, 27.5" wheels).

Please CYC - publish those curves! (or anyone else who has dyno'd this motor).
Click to expand...

Look on the bright side: if 300rpm isn't a typo then it explains a lot. Bad thermal design and an RPM a rider could never match explains my real world experience with this motor.
 
nervagon said:
Both the product page and the current manual list crank RPM at 300.

I found that old preliminary spec sheet that claimed 190, but for whatever reason it changed in the final shipping product.
Click to expand...
Hmm. That's wild they put that greater than sign. I measure unloaded about 3350 motor rpm with a fully charged 52v battery. Given the 15:1 gear ratio mentioned earlier that puts it at about 220 rpm which is roughly what I'd expect. I saw a post somewhere saying 3800 rpm design rpm, which still falls short of 300 rpm crank let alone higher than that. *Shrug* I guess it's not impossible, just seems crazy high. Maybe try your torture test on throttle only to get the rpm up higher if you can, guess that depends on bike gearing too though since if you don't have any lower gears left you'd have to travel faster to get the rpm up which would draw more power. Then again you've limited it to 700 watts, so it would probably just bog down until the crank rpm ends up the same anyway. I dunno, I'm not an expert on these things.

Follow up question, based on my again non expert understanding of motors, wouldn't keeping the same motor and same rpm but just lowering the battery voltage also raise the required current for a given power and thus end up with the same efficiency? The ebikes.ca sim seems to back this up. Motor Simulator - Tools
Two identical motors moving at the same rpm just with different battery voltages show the same efficiency. Seems like you'd have to rewind the motor instead if you wanted to change where it falls on the efficiency curve for a given cadence rpm.
 
Epithemeus said:
Hmm. That's wild they put that greater than sign. I measure unloaded about 3350 motor rpm with a fully charged 52v battery. Given the 15:1 gear ratio mentioned earlier that puts it at about 220 rpm which is roughly what I'd expect. I saw a post somewhere saying 3800 rpm design rpm, which still falls short of 300 rpm crank let alone higher than that. *Shrug* I guess it's not impossible, just seems crazy high. Maybe try your torture test on throttle only to get the rpm up higher if you can, guess that depends on bike gearing too though since if you don't have any lower gears left you'd have to travel faster to get the rpm up which would draw more power. Then again you've limited it to 700 watts, so it would probably just bog down until the crank rpm ends up the same anyway. I dunno, I'm not an expert on these things.
Click to expand...

Woah, man... 220 crank RPM is still really, really bad for a PAS motor and way above their already quite high preliminary design goal of 190rpm. OK, everything makes sense now.

So 48V: 203rpm
and 36V: 152rpm

Follow up question, based on my again non expert understanding of motors, wouldn't keeping the same motor and same rpm but just lowering the battery voltage also raise the required current for a given power and thus end up with the same efficiency? The ebikes.ca sim seems to back this up. Motor Simulator - Tools
Two identical motors moving at the same rpm just with different battery voltages show the same efficiency. Seems like you'd have to rewind the motor instead if you wanted to change where it falls on the efficiency curve for a given cadence rpm.
Click to expand...

No, I would drop to 36V @ 10A. That's why I figure that 36V at 360W would be my efficiency sweet spot. Why 10A? I drop to 52 @ 10A right now on long climbs.
 
So based on @Epithemeus testing at 52V, we can kind of estimate the cadence efficiency band at 36V would be within 50% to 80% of the max 36V rpm of about 152.

Lower Bound of Efficient Range:
Lower Bound=0.5×152
Lower Bound=76 RPM

Upper Bound of Efficient Range:
Upper Bound=0.8×152
Upper Bound=121.6 RPM

That makes 36V compatible with humans. And again, I think the nominal current for this motor is about 10A. So 36V at 360W really could be the sweet spot for this hardware.
 
Last edited:
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