DD alternative to mac

[Bouteille51]

Hi,

Sorry for this once again 'what motor' thread but I could not find a message answering my questions.

I have 2 ebikes with phaserunner controllers and mac motors.
The first one is rock solid, never had a problem configuring it and changing PR parameters, although the initial configuration was long (Kp/Ki).
The second, with a different version of the phaserunner was extremely difficult to configure. I never managed to get a configuration as confortable as the other one (no way to get a nice and soft start without helping the motor first).

I recently got a problem (throttle cable) with the second bike and after I fixed the cable I messed a bit with PR parameters and now can't get a workable configuration (fighting with overcurrent fault, autotuning, etc...).

I read a lot of messages discussing similar problems with MAC+PR so I decide to change the motor to a new Direct Drive one, and see whether the PR can do something with it or not.

I'm looking for sometthing comparable to a mac 8T.
I am not an offroad or extreme rider but I'd like to be able to reach 50 km/h (52V battery), get some nice torque for steep hills (not very long ones), and a smooth start without pedalling...
I would prefer a smaller diameter if possible, and the possibility to fit a 7 speed cassette or freewheel.

Ideally, I could order the motor with a rim pre-laced...
Can you help me identify the motor of my dreams ?

So far I identified:

Grin	All-Axle Rear	Perfect motor ? Way too expensive !! >1000$ all included !!
Mxus	DDR-40 1000w
Mxus	DDC-40	Difference with DDR-40 ?
Crystalite	H3540
Crystalite	UFO-3540 Rear	Difference with H3540 ?
Leaf	26 inch 60V 2000W	Single side cover design easier for eventual maintenance ? More reliable for water ingress ?
Leaf	26 inch 48V 52V 1500W	Differece with previous ?
9C / Ozo	RH212

Could you maybe comment on this list (and notes/questions), and eventually suggest other options ?

Thank you very much !

 

[amberwolf]

Well, to get the same torque with a DD as with a geared hub, it's likely to take up to several times the current to do it, since you don't have the gear multiplication.

What does the ebikes.ca motor simulator show is needed for your specific conditions with the motors in your list? (for those it has in the sim, or those you can find properties for to use the custom option). That may help you figure out if they could even do what you want, with the PR you have (or if you have to get a bigger controller and possibly battery, etc).



Smooth start depends a lot on the motor hall sensors and phase currents involved--the higher the phase currents, the more likely to have noise induced from those into the hall sensors themselves and their signal wires/etc and cause problems with the controller reading them and providing correct phase timing.

It also depends on the controller's ability to clean that up and work anyway, or to detect phase current changes and fix timing issues based on that. I don't know how good the PR is at it vs anything else, but the PRv6 drives my SB Cruiser trike's rightside motor well enough even with heavy loads from a stop, even for the many (most) times I cannot push hard enough to start it myself. I've used the GMAC and that was better at startup torque than the DD Ultramotor I'm using now--but the UM is silent and the GMAC is not, among a few other issues, and I value the silence even more than the torque, since the UM torque is adequate, though not overwhelming.

The second, with a different version of the phaserunner was extremely difficult to configure. I never managed to get a configuration as confortable as the other one (no way to get a nice and soft start without helping the motor first).

Was the different version older or newer? If older, were there any firmware updates possible to correct it's issues? (or downgrades for a newer version)

Was it ever tried with the motor from the working system? (perhaps there was an issue with the second motor itself, vs the PR)

I recently got a problem (throttle cable) with the second bike and after I fixed the cable I messed a bit with PR parameters and now can't get a workable configuration (fighting with overcurrent fault, autotuning, etc...).

What if you reset the PR completely to factory default, power cycle it at least once, and reupload your previously working settings to it from whatever files you saved when you initially got it working?

If that doesn't work, then there's probably something wrong with the PR itself (unlikely the motor itself would have been damaged by tuning, unless you were able to detect overheating), since all settings would then be back to the way they were when working and it wouldn't be a setting interfering.

 

[Bouteille51]

Hi, thank you so much for your help on this.

Unfortunately I ran out of logic with this second bike... I got tired of changing parameters/cables etc...
It used to work better with the other mac motor but not anymore. It has the first version of phaserunner while the other bike is a V2.

I tried setting all to default and start from scratch but can't figure a way to get back to an acceptable working configuration.
As reported in other threads, it seems to behave differently if I use different versions of the software suite for programming it...

Anyway it is known for not being super happy with mac motors, so I'm trying to make its life easier with a DD motor (this mac will be useful as spare for my other bike).
If it does not help I'll know there is something wrong with the controller and I'll go for something else (maybe VESC), but for now I'm trying to avoid that as it would require to recable all the bike and the PR fits nicely in my current setup

Ok for staying in reasonable torque range, I'm not a crazy rider... And silence sounds nice indeed

Ok thanks I'll try to get more familiar with the simulator but not sure if the motors in the list are there (leaf ?)

 

[amberwolf]

Unfortunately I ran out of logic with this second bike... I got tired of changing parameters/cables etc...
It used to work better with the other mac motor but not anymore. It has the first version of phaserunner while the other bike is a V2.

If it's behavior has changed, using identical settings that worked before, with a motor known to work perfectly on the other PR, then something has changed in the controller itself (or the wiring between it and the motor). Either it's a setting that isn't being cleared by the reset, or it's a hardware issue of some type. (which is usually a wiring or connector fault more often than anything else).

Does this motor work fine on the bike that normally works?

I certainly understand the frustration--I have quite a few things of all sorts of technologies I "gave up on" because they simply can't be used without figuring out what wierd thing keeps them from doing what they should do, and not doing whatever weird thing they are doing instead. Some of them I spent years, and perhaps thousands of actual man-hours, trying to make work, because there's nothing inherently wrong with any part of the system...they just don't work together.

I tried setting all to default and start from scratch but can't figure a way to get back to an acceptable working configuration.
As reported in other threads, it seems to behave differently if I use different versions of the software suite for programming it...

That sounds like the suite itself is sending different data to it; if it needs a particular version of the suite for it's firmware version, you may have to use that specific one (Grin ought to be able to tell you that, even if they can't troubleshoot the system).

But what I was really asking / suggesting was that you use your known-working saved settings after doing a reset. Not just retrying a from-scratch setup, but using the ones you know worked either from a saved file, screenshots, notes, etc. (the saved file should be the best since there's much less chance of a missing or wrong setting. )

Anyway it is known for not being super happy with mac motors, so I'm trying to make its life easier with a DD motor (this mac will be useful as spare for my other bike).

As long as the problem is not an overcurrent issue, it might be easier. But since phase currents will be higher (possibly much higher) to do the same thing with a DD as a geared, especially from a stop / on steep hills, if it is an overcurrent issue it will likely have worse problems.

The main reason controllers have trouble with MAC (and other high-pole-count motors with gear reductions) is because their ERPM is high, so above a certain speed (variant upon wheelsize) the controller can no longer keep up with the motor's sensor / phase BEMF and provide proper phase current timing. I'm not certain if that's why your PR has issues, but it's the most likely one, and if so would not happen at startups, and would behave normally until a certain speed was reached. It could also happen if the wheel left the ground for any reason, on bumps or curb hops or potholes, and was able to speed up to whatever point the controller couldn't keep up.

If it does not help I'll know there is something wrong with the controller and I'll go for something else (maybe VESC), but for now I'm trying to avoid that as it would require to recable all the bike and the PR fits nicely in my current setup

FWIW, you shouldn't have to rewire the whole bike--you could just match the controller-side connectors of whatever controller you get to what you have now.

Ok for staying in reasonable torque range, I'm not a crazy rider... And silence sounds nice indeed

It's not whether you're a crazy rider, but how much torque is required to go up the hills you have, how much current is required to do that with any specific motor, and whether your controller (and battery!) can provide that for long enough to go up the hill at the speed required.

Ok thanks I'll try to get more familiar with the simulator but not sure if the motors in the list are there (leaf ?)

I don't recall--but I think there are settings you can use for them somewhere in the big leaf motor thread.

But if you find that the ones that are in there (like the GAA) can't do what you're after without a bigger controller or battery, then it's likely the others couldn't either. Then at least you'll know ahead of time the other changes your system would need.

The worst case is if you have to startup from a stop on one of those hills, as that takes the most power, and without hte gear reduction it's likely to be significantly greater. But I don't know your conditions, system weight, etc., so can't verify any of that.

 

[neptronix]

RH212 is the closest DD equivalent to a MAC. At ~12lbs, the power to weight ratio is as good as it gets in the ~1000w power range.

The next step up would be a leafbike 1.5kw, which is realistically, a ~1800W rated motor. It will blow the doors off the MAC, but you don't sound like you need anywhere near that amount of power.

If i was in your position, i'd switch to a different controller instead. MAC is a very nice motor and successfully driving it with a phaserunner seems difficult.

 

[Bouteille51]

Does this motor work fine on the bike that normally works?

I certainly understand the frustration--I have quite a few things of all sorts of technologies I "gave up on" because they simply can't be used without figuring out what wierd thing keeps them from doing what they should do, and not doing whatever weird thing they are doing instead. Some of them I spent years, and perhaps thousands of actual man-hours, trying to make work, because there's nothing inherently wrong with any part of the system...they just don't work together.

The motor is fine on the other bike, i suspect something changed in the controller (or I was much more patient setting it up back when I assembled this bike) but can't figure what. Frustration accumulated indeed but I'd like to give this controller a chance to be useful again... Well I must admit it's a chance for me to be a bit lazier for getting this bike running again...

Anyway this bike was never as comfortable and punchy as the other one, so there must something different inside the 2 PR... Hence the idea to give it a chance with another motor type.

Changing the controller would probably mean rewiring the bike because it is in a very tidy place right now (very close to the wheel), and I'm not sure I can find another one with same form factor and robustness (the potting is a nice thing too).

Worst case: in the end I'll have to change the controller but I got an extra motor and a zombie phaserunner in the process, maybe an excuse to start a new project

But what I was really asking / suggesting was that you use your known-working saved settings after doing a reset.

Shame on me regarding the setting, I don't know why I never saved the parameters as files but was relying on saved states of my virtual machine... Which of course does not work anymore after updating vmware.
Worst part is that I work in science and I am very annoying with students regarding reproducible and reusable research... Apologies to all of them

The main reason controllers have trouble with MAC (and other high-pole-count motors with gear reductions) is because their ERPM is high, so above a certain speed (variant upon wheelsize) the controller can no longer keep up with the motor's sensor / phase BEMF and provide proper phase current timing.

Agreed, and if I remember correctly, it was not obvious to find a FOC controller able to handle the >60kHz ERPM.

But if you find that the ones that are in there (like the GAA) can't do what you're after without a bigger controller or battery, then it's likely the others couldn't either. Then at least you'll know ahead of time the other changes your system would need.

Thanks for the suggestion I'll play with the simulator to get a basic idea of geared vs direct.
If you want more detail my battery is 14S5PLi-ion ~17.5Ah, I don't need more than 15km range, and no more than 50km/h max (most of the time around 25), my weight is 75kg and I give very moderate amount of human power (=not much to negligible). Steepest hill is 15-20% but only for ~100 metres so I should consent making some efforts there

RH212 is the closest DD equivalent to a MAC. At ~12lbs, the power to weight ratio is as good as it gets in the ~1000w power range.

The next step up would be a leafbike 1.5kw, which is realistically, a ~1800W rated motor. It will blow the doors off the MAC, but you don't sound like you need anywhere near that amount of power.

Ok thanks a lot, I'll use it as a base reference in the simulator.

 

[Bouteille51]

Thank you for your suggestions.

After playing a bit with the simulator, the RH212 seems indeed to be the closest to the mac motor:
Grade 0% - Throttle 100%
Grade 10% - Throttle 85%

Other motors deviate more and more (Grade 10% - Throttle 85%):
Crystalyte H3540
Leaf 35mm 5T
Grinv V2 FST

Not sure if I am reading the graph and using the simulator properly, but the differences don't seem very large between the RH212 and Mac 8T.
Is there any point I should pay specific attention to in these comparisons ?

 

[neptronix]

If you want even more torque and better efficiency ( therefore less heat ), i'd recommend running the smallest motor wheel you/your bike can tolerate.

RH212 gets it's additional torque potential thanks to a few additional poles and a bit taller stator versus most DDs. It's a unique motor design.

Nothing in particular to pay attention to in those, other than if it matches your actual conditions and bike. I find that the simulator is very accurate.

 

[Bullfrog]

My first choice would be to get the MAC working but I am probably the biggest MAC fan in the world .

After that, I'd go with the Leaf motor. Everything in your list is pretty good except the MXUS...I have never owned one but from what I have read, the quality of construction with the MXUS motors is not as good as the others. Crystalite makes a good motor but they are usually a little pricier than others that are equivalent. The Grin All Axle would be good but they are probably the priciest.

Like Amberwolf said, you are not going to find a DD motor that has as much torque per battery amp as a MAC so prepare yourself for disappointment when it comes to torque/acceleration of a DD motor compared to a MAC. On the other hand, a DD motor won't over heat as easily as a MAC. I didn't choose the RH212 because they had some manufacturing problems that have probably been solved now...some of the castings were very porous and a few motor cases broke. If you decide to go with the RH212, I'd only buy from Grin Tech to ensure you have support in the event there is an issue.

Knowing what I know today, if I had it to do all over again and wanted a DD motor, I'd go with the Leaf...I'd run a 14s/52v battery and get the 4T winding. If you use the Grin Tech Motor Simulator, the Leaf motor is in the drop down menu but it has not been modeled to give steady state temperatures...you can sub the RH212 and manually adjust the Kv to get the same top speed you'd get with the Leaf and the temperatures will be close enough to use for estimating the temps the Leaf will have.

You mentioned small diameter....bad idea because the torque a motor produces is proportional to the diameter so a small diameter DD motor would suck from the acceleration stand point . The MAC does it with the planetary gears...it multiplies the torque produced by the motor times FIVE .

 

[E-HP]

Thank you for your suggestions.

After playing a bit with the simulator, the RH212 seems indeed to be the closest to the mac motor:
Grade 10% - Throttle 85%

Is there any point I should pay specific attention to in these comparisons ?

If you have hills, the R212 will never overheat at 10% grade, when adding Statorade. Options for the MAC with comparable cooling may be messier.

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