Dji avinox- Amflow

[Rob Rides EMTB]

The reviewers are all using boost mode because it's neat and exciting. I don't think you'd use it a lot as an average rider, but it'd be great to have for certain trail sections.

It's always good to have more power, since you don't have to use it if you don't need it. If it was just powerful it wouldn't be very exciting. It's the fact that it's powerful *and* light/compact that is exciting.

It’s a bit like the ludicrous mode in a Tesla. Yes, it’s a ton of fun. If you had it on you bike I bet you’d use it more than you think

 

[Redlemon]

The DJI needs a 5 speed wide ratio heavy duty transmission with that sort of power!

More eMTBs should come with the new Shimano CUES or XT LinkGlide 11 speed drivetrains, perfect eMTB drivetrain at a very reasonable price.

That new DJI motor is going to mess up the EWS-E for sure if a team finds a way to run it, motor is going to be like 20 minutes faster than other teams over a few stages without even putting in more work.

Anyway, I think the DJI system is showing that eMTB motors should stay within a certain power band range and instead focus on reliability, smoothness, integration and efficiency.

 

[Mabman]

Personally I am less interested in peak power as my Bafang M620 has got that and more but it is a tank at 62lbs., a mullet and I want a full 29"er again, also not much fun to ride conservatively for distance. Although ripping around the logging roads does remind me of my old Yamaha 125 a bit. I'm intrigued by the Avinox and the ZF as well for my next bike for sure. Matters not at all if it is made by one ot the major brands I just want a full power bike that weighs as much as possible less than my current bike.

BTW, the contact number for Amflow US is in the 262 area code which is in SE Wisconsin.

 

[John_A]

Doubt it will cause a whole lot extra wear, but if it was a huge concern dropping down to a 10 speed would likely be more than enough. Motors with more power (although not eu 250w legal) have been on the market for a while, dropping down to a 5 speed would be massive overkill

Interesting point - How the heck is this UK legal? We all know all of the manufacturers are bending the rules to claim class 1 compliance, but this sort of power is approaching M600 levels - How do they make a claim that it's 250W?

 

[Mteam]

Interesting point - How the heck is this UK legal? We all know all of the manufacturers are bending the rules to claim class 1 compliance, but this sort of power is approaching M600 levels - How do they make a claim that it's 250W?

Presumably the same way the bosch, shimano, brose motors are legal despite putting out 600+w peak power.

I think the motors (in order to be classed as a pedelec) need to slowly back off the power so that when measured over a time period (not sure what the time period is, maybe 30 minutes) the average power is no more than 250w.

I've felt my bosch gen4 throttling the power back when climbing a steep hill in turbo mode.

The legislation talks about the motors needing to have a 250w nominal (the word nominal being key) power output to be classed as a pedelec, the rules don't specify any peak power limits, as far as I know.

It would be interesting to get more understanding about how each of the motors manage to stay within the 250w nominal power limit

 

[Rando_12345]

Interesting point - How the heck is this UK legal? We all know all of the manufacturers are bending the rules to claim class 1 compliance, but this sort of power is approaching M600 levels - How do they make a claim that it's 250W?

Mteam has a good answer, but to complement: Rob mentioned on the podcast that DJI claim they have more precise speed and torque sensors, which is how they can inject more peak watts over fractions of a second, yet still have an overall wattage under 250w.

I'm somewhat inclined to believe them from the point of view that the early ride reports state how easy the motor is to get on with and there doesn't seem to be a constant burnout/wheelie issue (despite rob's video above)

 

[John_A]

Mteam has a good answer, but to complement: Rob mentioned on the podcast that DJI claim they have more precise speed and torque sensors, which is how they can inject more peak watts over fractions of a second, yet still have an overall wattage under 250w.

I'm somewhat inclined to believe them from the point of view that the early ride reports state how easy the motor is to get on with and there doesn't seem to be a constant burnout/wheelie issue (despite rob's video above)

It's nonsense though - It's basic physics if you deplete a 800WH battery in boost mode in an hour your power consumption averaged 800W

 

[Dax]

It's nonsense though - It's basic physics if you deplete a 800WH battery in boost mode in an hour your power consumption averaged 800W

It’s also basic physics that your motor is not 100% efficient in converting that 800w into motion, therefore depleting a 800wh battery in an hour doesn’t mean the motor output is 800w.

 

[John_A]

It’s also basic physics that your motor is not 100% efficient in converting that 800w into motion, therefore depleting a 800wh battery in an hour doesn’t mean the motor output is 800w.

Wasn't trying to be too scientific. OK - so a brushless motor could be 85-90% efficient so 650-700W of power, still a lot more more than 250

 

[Mteam]

It's nonsense though - It's basic physics if you deplete a 800WH battery in boost mode in an hour your power consumption averaged 800W

But can you drain an 800w battery in an hour of continuous riding? The continuous bit is important as I think the nominal measurement includes any stopped time you might have, or time spent coasting downhill where the motor power output is 0w.

Or does the motor start to throttle, making the motor average 250w or less. I'd be genuinely interested to know what happens with all the different motor types in this area.


There's also a matter of losses in the system ie 800w electrical input does not equal 800w output, it will lose a bit of power converting fro electrical energy into movement (due to heat, running the electronics etc), but I guess this will be minimal in reality.

I have no idea really how all this works, so I'm just speculating, but would be good to understand it.

I don't think it's as simple as the manufacturer lying to the regulators, and just stating their output is 250w nominal, but in reality they'll let you have 600-1000w for as long as your battery can deliver it.

So far most manufacturers downplay their peak power outputs and don't seem to make a big deal of it in the marketing literature (they do talk about peak torque and how much power it can output as a percentage of what you are inputting) , dji are not following this approach, so if they're promising big power it would be good to understand any constraints on accessing this power. The implication is it's available whenever you want for as long as you want (except for the 30 boost mode), and as you say this is in contradiction to the pedelec rules.

 

[Hattori-Hanzo]

It's impressive results for sure.

I'd be interested to see how the DJI motor compares using its second highest mode, not using the 30 sec boost mode.

 

[John_A]

But can you drain an 800w battery in an hour of continuous riding? ......................

Who knows . It just seems odd that a motor that's 25% quicker than a Bosch CX can have the same 'rated power'. You'd be chased off a trail riding a Bafang M620 but not with an Avinox, yet the actual power they put down on the wheels is similar. Not complaining - more power = good in my book

 

[Mteam]

Who knows . It just seems odd that a motor that's 25% quicker than a Bosch CX can have the same 'rated power'. You'd be chased off a trail riding a Bafang M620 but not with an Zvinox yet the actual power they put down on the wheels is similar. Not complaining - more power = good in my book

Would be good, if you had a long enough hill, to test them all over a much longer time period than just a 30 second climb , if they're All meeting the same 250w nominal limit then they should all have very similar times up this imaginary long hill.

The various low power ebikes (tq, Levo sl, fazua r60 etc) should also be the same time up this hill.

Whereas your bafang should be substantially quicker, given that it's not bound to comply with the 250w legislation.

 

[whitymon]

I am not sure this would be possible to go full power from 100 to 0%. Heat would be of an issue no?

That is what's happening on the Rocky mountain currently, you are asked to cooldown!

Not sure if it totally relate but on a surron if you run at max power for too long - like top speed from point City A to City B - which the bike is not done for, some parts start becoming extremely hot and starts melting.

 

[John_A]

I am not sure this would be possible to go full power from 100 to 0%. Heat would be of an issue no?

That is what's happening on the Rocky mountain currently, you are asked to cooldown!

Not sure if it totally relate but on a surron if you run at max power for too long - like top speed from point City A to City B - which the bike is not done for, some parts start becoming extremely hot and starts melting.

Suppose if you draw 100W for 15 minutes then break down and do nothing for the next 45 that's an average of 250W . Who knows

 

[Rob Rides EMTB]

Would be good, if you had a long enough hill, to test them all over a much longer time period than just a 30 second climb , if they're All meeting the same 250w nominal limit then they should all have very similar times up this imaginary long hill.

I actually want to do this, I know of a super steep climb upto the quantock hills that must be at least 1000ft of intense steep gradient that will really stress a motor.

 

[Mteam]

I actually want to do this, I know of a super steep climb upto the quantock hills that must be at least 1000ft of intense steep gradient that will really stress a motor.

Sounds good, will be interesting, but I reckon 1000foot is not long enough to bring this 'nominal 250w' rule into full play, but would give a good idea of how each of the motors performed over a longer climb, in theory they should be much closer in performance than on the 30 second climbs.

 

[robbydobs]

The motors take into account all sorts of factors to put out the maximum power, including the gradient.

Are all those taken into account when the power is measured to meet the 250w limit?

I'd guess that on the flat, at maximum 15.5mph assist speed, they'd all be using less than 250w. Maybe thats how they measure the power? And also why Bosch, Shimano etc are being so much more pro-active in preventing them being derestricted.

 

[John_A]

I actually want to do this, I know of a super steep climb upto the quantock hills that must be at least 1000ft of intense steep gradient that will really stress a motor.

Crack on then , and get a ride review of that lightcarbon build while you're on. A busy day at the office sounds more fun for you than me!
Amazed at how much quicker that DJI got up the ill compared to the Bosch, if you look at the results of similar tests done by Epic Ebikes, the DJI is on-par with a Bafang M620 when comparing performance gains over the Bosch

 

[John_A]

The motors take into account all sorts of factors to put out the maximum power, including the gradient.

Are all those taken into account when the power is measured to meet the 250w limit?

I'd guess that on the flat, at maximum 15.5mph assist speed, they'd all be using less than 250w. Maybe thats how they measure the power? And also why Bosch, Shimano etc are being so much more pro-active in preventing them being derestricted.

Apparently that's about right, 250w is about what it takes to travel at 15mph on the flat.

 

[B1rdie]

I actually want to do this, I know of a super steep climb upto the quantock hills that must be at least 1000ft of intense steep gradient that will really stress a motor.

It would be nice to have some more riders, with different levels of skill and fitness to take part on the test. I would volunteer

 

[RichMorr]

It would be nice to have some more riders, with different levels of skill and fitness to take part on the test. I would volunteer

I was thinking this a mega race but not just the current crop of motors, but the gen 1 Levo sixfatty, early Bosch, Shimano, the TQ120 on the Haibike.

I’m sure the biggest EMTB channel could pull a few stings and get the ZF and brose drive peak 3 for a past, present and future motor race.

 

[Mikerb]

A motor draws more current depending on the load.....e.g riding uphill. More current means more heat and at a specific level that heat will destroy the motor. So nominal power ratings (should) avoid any motor damage regardless how long the motor is running. As the motor draws more current to deal with gradient etc (higher power modes) the motor should stay within temperature limits set in firmware. So a well designed motor and firmware combination should allow continuous riding using all the modes without thermal cut off.
The DJI 30 second ultra boost mode obviously goes beyond those limits ( peak power) hence the 30 second limit........so why can you then re- engage that mode without delay??

 

[Rando_12345]

@Rob Rides EMTB on the unlikely chance that you travel to Nice/Finale area with the DJI in the near future:

This segment, less than an hour from Nice airport is a ~10 minute technical climb. Chemin Saint Martin - Portail Climb VAE | Strava E-Bike Segment in Tourrettes-sur-Loup, Provence-Alpes-Côte d'Azur, France

The KOM time is 9.28 on a bosch Race motor, by the multiple E-bike XC World Champion Jerome Gilloux. Second place is another pro rider on the Bosch Race, who won multiple power stages in the E-EDR this year.
A fit amateur on a Bosch race did a 10:22, and another fit amateur on a regular Bosch gen 4 did a 10:42.

So if the DJI can maintain its 10-20% lead over a 10minute climb, a good rider on the AMflow can go out there and beat the world champ . The video title writes itself!

 

[Mikerb]

As an aside I raced a Mini offroad years ago. I tuned the 850cc engine to produce more power than a 1275cc Cooper S........it won races but had to be rebuilt every 3rd race!!
An emtb motor consists of much more than the electric motor itself.......reduction gears, bearings, final crank drive etc. The weakest part of my 850 mini was the 3 bearing crank despite the reduction of the standard long stroke. It needed extra water and oil cooling and a rev limiter to survive at all.
Back to the DJI.......I am inclined to trust the likes of Brose and Bosch with their very similar approaches to peak power. Despite DJIs doubtless electric motor experience with drones those devices only have to deal with fairly constant and predictable forces ( weight and gravity)

 

[TimC7]

A motor draws more current depending on the load.....e.g riding uphill. More current means more heat and at a specific level that heat will destroy the motor. So nominal power ratings (should) avoid any motor damage regardless how long the motor is running. As the motor draws more current to deal with gradient etc (higher power modes) the motor should stay within temperature limits set in firmware. So a well designed motor and firmware combination should allow continuous riding using all the modes without thermal cut off.
The DJI 30 second ultra boost mode obviously goes beyond those limits ( peak power) hence the 30 second limit........so why can you then re- engage that mode without delay??

Heat dissipation is key and this would depend on the external temperature. If ultra boost mode is monitored using temperature sensors and limits are not reached then presumably the software would allow it to be re-engaged.

 

[Bengy22]

Interesting point - How the heck is this UK legal? We all know all of the manufacturers are bending the rules to claim class 1 compliance, but this sort of power is approaching M600 levels - How do they make a claim that it's 250W?

Everyone else pretty much covered it but rated power is basically how much power it can sustain without overheating in a set time, no law around how high you can peak. I believe for the EU it was over 30 minutes but I'm not 100% sure on that. I would actually love to find out more on how this is tested as a lot can change the outcome of the rating. Higher ambient temps and airflow can play a big part. Also could be noted that with a 400% assistance rate to get the full 1kw you need to also hold 250w yourself, most people probably are not going to hold that for long. And I assume DJI was smart enough to implement a temp sensor to rollback power if needed. DJI is pretty much doing what everyone else already did but decided to push the peak power higher. We already have motors in the space peaking around 800w (despite what the manufactures claim, been proven to lie).

What's really interesting to me is DJI built this motor while maintaining a 36v system. Amps is heat, and for 1kw the battery will need around 28a for that. (this also assumes the 1kw quote is on the battery side before inefficiency found) but if they moved to a 48v that's 21A or roughly 25% less amps, or in a perfect world 25% less heat. Which could mean to keep the rated power at 250w you would have to build the motor smaller to take less heat, aka less weight as well.

As for Rob I would really like to see how this motor compares to the bosch gen 5 while in Turbo, personally not a fan of needing to move into a special mode that only lasts 30 seconds. And I bet the race would be fairly close

 

[Gigs]

@Rob Rides EMTB

I note you can setup wheel size and cassette etc in the Avinox app.

Question: If you have a 29er wheel on the bike and set the app to 27.5 do you have a speed increase above the 25kmph cutoff? You may need GPS to measure this as the app would be reporting incorrect speeds based on wheel circumference. I'm sure DJI has GPS and other sensors in place to stop this but worth the question?

 

[Mabman]

"What's really interesting to me is DJI built this motor while maintaining a 36v system. Amps is heat, and for 1kw the battery will need around 28a for that. (this also assumes the 1kw quote is on the battery side before inefficiency found) but if they moved to a 48v that's 21A or roughly 25% less amps, or in a perfect world 25% less heat. Which could mean to keep the rated power at 250w you would have to build the motor smaller to take less heat, aka less weight as well."

I wondered about this also and it seems the ZF does have a 48v system. The Rocky Mtn. proprietary motor as well. I am also curious as to how they got the 800wh battery to be as light as advertised. Energy density using cells is pretty even across the board and it looks like the dt isn't all that big?

 

[DirkWisely]

Yeah I'm not really sure why you wouldn't build higher voltage when building a new system. Presumably they have a reason.