29mm to 35mm to 50mm -> My evolution to the Cromotor

[methods]

They are going to work prettier than they look :wink:

I think these may just be able to blow any hub around before they give out. Trick will be finding people willing to find out A CroMotor is expensive to replace and they are getting hard to find.

Today I am going to do the stall test - that is really the deciding factor. If it can take 30 seconds of being shorted into a CroMotor it should be able to take just about anything.

-methods

 

[Alan B]

Looking really good!

Hope they are short enough to fit in my Borg frame. Had to cut 3/8" off the one I have to get it to fit. But we have the technology to do that if needed.

 

[methods]

These controllers actually have a large 1" void in them for wire routing. You could take that up if you needed - but you would also need to re-do the end caps to have the phase and power wires exit from under the board. All of our heavy wires go to the bottom of the board. This solves the issue of 8AWG and dual 10AWG not fitting into the holes and it totally clears up the top for troubleshooting and smd access. On the bottom the phase wires do double duty beefing up the center pads. At first we relocated the power to the middle of the 6AWG main power trace... but ended up relocating it again to the other side of the board closest to the wire panel. Cleans up and shortens up things quite a bit.

-methods

 

[Alan B]

I don't need that much. The one I have was 1/8" too long, I took 3/8" off, was still lots of room for the wires.

 

[Alan B]

U haz tranzwarp drive now.

That thing sounds almost like a TIE-fighter screaming by, ya know?

We need to get the sound effects chips working. With a knob that has various interesting sound settings.

 

[gensem]

you look good in blue meth.... +1
btw i think john deserves to be part of the club

 

[John in CR]

you look good in blue meth.... +1
btw i think john deserves to be part of the club

Those blue cases are awesome and would match the cargo rocket I'm building for Hubmonster. Motor melting obviously isn't happening, since my Steveo 36 is so stressed at the 425A/550A settings I've run it at for 3 months. Steveo built it up from those first run 36's about 2 years ago, so Hubmonster would be a good test of the newer version boards and those high quality surfboard caps to see how much they help keep the controller heat down with a low L and R motor. The Steveo 36 requires a blower to ventilate in order to stay alive at anything above 200A with Hubmonster. I'd need 250-300A battery side 340-400A phase to make the motor sing though. I've got a souped up 18fet that still has a low voltage rail issue that's never been run to offer in trade, but I'm done with higher end controllers since the 6 phase motors I'm into now run fine on a pair of cheapies.

 

[methods]

We are working on a batch of fan cooled 6fet controllers right now.
100V 50A in a 6fet case - for men who like a tight package.

Programmable with a full feature set

For the 24 fet I am trying to find a way to fan-cool the case without actually blowing air through the inside. Blowing dirty ass air over the circuit board is a guaranteed fail after enough time unless there is a really thick conformal coating or a filter on the inlet. Better would be to just cool the case externally - like a computer fan on top of a chip.

-methods

 

[hjns]

You may want to go Lebowsky for cooling. Separate alu coolerpipes without any external air exposure of circuitboard. Maybe ask him for permission to copy first...

 

[methods]

I let my wife take off with the kid for a week and look at what she is already teaching him.
That bottle should be in the recycling bin...




-methods

 

[hjns]

Very cute!

No wonder he is sleeping so well

 

[steveo]

Hey methods

A couple questions for ya..

how is the torque and speed in comparison to say a x5303 in a 20"

What kind of freewheel you running on the kmx?

What do i need to do to become a beta tester for this motor?

Have you pushed 150v into yet, i almost broke my face on my x5303 on my kmx... See youtube video

Thanks
-steveo

 

[Stochastic]

Here are a few pictures from the new 24" test machine I built.
It has a nice set or forks off a Zero Bike, 3" tires which fit perfect on the 24" rims and provide a ton of traction, and a custom battery holder from a converted zero battery enclosure.







It pops the front up with the littlest effort but feels amazingly stable.
Videos to come.
Gonna try and turn it up to 11. 8)

-Matthew

 

[methods]

hmmm.... we have to paint the end covers black.

-methods

 

[methods]

Hey methods

A couple questions for ya..

how is the torque and speed in comparison to say a x5303 in a 20"

This is a much lower KV motor and it is in Justins simulator under NoName. The simulation is only accurate at lower power levels - so if you want to compare do it at lower currents.

What kind of freewheel you running on the kmx?

18T BMX. The skinny kind, not the wide kind. $12 at the LBS. Even with a monster Chain Ring up front I still cant pedal.

What do i need to do to become a beta tester for this motor?

There was a huge sales thread and they all sold out. I bought 10 of them and I have 3 left. They are $600 and for sale on my website.

Have you pushed 150v into yet, i almost broke my face on my x5303 on my kmx... See youtube video

I need to remember to look that up. I have decided to limit myself to 100V and down due to the current state of mosfets available. I believe the point of diminishing returns comes at 100V as you have to forgo the 4110... battery management gets a lot more complicated and expensive and human safety also becomes a concern. We were always current limited (to about 50A) and this is what lead us down this path of higher and higher voltage. Now that we have controllers that can punch out 250 Battery amps a 100V controller should provide more power than you can ever use in an ebike.

btw: Your early work with the 24 fet controllers came in very handy during our development and respects will be paid in the build thread.

-methods

Thanks
-steveo

 

[methods]

I think the limiting factor with my cro right now is the 300A battery current - I think that is eating up my acceleration. Jeremy came up with the number and at first Luke was giving me a hard time that it was going to saturate the motor and we should do 200A... but after seeing the dyno results I think it would not hurt to put another 100A in there.

I rigged up the bike with my Ugga front light and absolutely blinding rear red blinking light - both run from a 4S Hardpack. Nice little programmable LED driver boards in there.

Found my KMX trike is falling apart at the seams. All of the fastened joints have worked loose so it is time to go over the bike and service it. Many of the fasteners were not even tightened up since the factory assembly... so things like the steering is all over the place.

Spokes are all looser than hell too on my 32hole rim. The Zero rim is holding strong. My source for those dried up so I may have to hit Ypedal up for a laced 20" wheel with hub and a 20" rim. That will give me zero rims all around - which are quite wide - and can probably accommodate some serious scooter rubber. Although it pains me to start adding more and more weight to this thing - I think it is time. Traction and the lack of suspension are a real problem.

-methods

 

[liveforphysics]

but after seeing the dyno results I think it would not hurt to put another 100A in there.

We can measure the torque vs current and graph it and find the saturation point. Then we don't have to guess, we can know.

 

[methods]

We can measure the torque vs current and graph it and find the saturation point. Then we don't have to guess, we can know.

Dont tempt me - I have lights on my rig and it is only 2 miles from my house to your shop I will ride that shit right over there.
But... why would I go do dyno testing when I could just sit and home and work on this other stupid machine that I built It is called "the time waster" and it is more effective than television or a wife & kid.

-methods

 

[methods]

We can measure the torque vs current and graph it and find the saturation point. Then we don't have to guess, we can know.

Dont tempt me - I have lights on my rig and it is only 2 miles from my house to your shop I will ride that shit right over there.
But... why would I go do dyno testing when I could just sit and home and work on this other stupid machine that I built It is called "the time waster" and it is more effective than television or a wife & kid.

Found some new Music - Adrian Sherwood. I like it
https://play.google.com/store/music...idW0tQjQ0a3N6YWRvbjUyNXF4Z2twMnY1NDZjZjJpIl0.

-methods

 

[John in CR]

but after seeing the dyno results I think it would not hurt to put another 100A in there.

We can measure the torque vs current and graph it and find the saturation point. Then we don't have to guess, we can know.

I thought from an earlier post by Methods that you guys already found saturation, well at least the peak power when the motor was extremely hot. He mentioned 50% efficiency at peak power input. Isn't that full saturation with the motor at that temperature, or does peak power occur at a different point than saturation? Also, what was peak phase current, since saturation is based on phase current, not battery current?

 

[methods]

Peak power always occurs at 50% efficiency no matter how low you set the current limit.
The saturation current is a fixed point where adding no more current will increase power... so you would start to drop below 50% efficiency.
(as I understand it)

We dont know the peak phase current was - only that we were on the 150A battery limit.

-metho0ds

 

[methods]

I thought from an earlier post by Methods that you guys already found saturation, well at least the peak power when the motor was extremely hot.

The only thing we really discovered was how much load it took to get my controller to hang on the 150A input limit. You can see from the rest of the videos that all we were doing was sneaking up on that limiter.... and hp was going up each time load went up... so no way are we saturated yet. Now we need to raise the limits and keep adding load until efficiency drops below 50% - or we let smoke out. As I understand it - that is the plan.

-methods

 

[John in CR]

I misunderstood then, because I thought you said you already hit that 50% threshold essentially right on the button. A hot motor vs a relatively cool one will make a huge difference in power though.

That's why I don't even use temp sensors, since I have enough load to tell when power drops off from hot windings. I back off immediately and the windings cool quickly as that heat spreads to the iron of the stator, so as long as I keep the load light and rpms up the motor is able to shed the heat without a failure and get down to reasonable temps pretty quickly.

 

[The Mighty Volt]

Here are a few pictures from the new 24" test machine I built.
It has a nice set or forks off a Zero Bike, 3" tires which fit perfect on the 24" rims and provide a ton of traction, and a custom battery holder from a converted zero battery enclosure.

View attachment 2

View attachment 1



It pops the front up with the littlest effort but feels amazingly stable.
Videos to come.
Gonna try and turn it up to 11. 8)

-Matthew

I like that bike a lot, lovely forks, well done.

 

[John in CR]

Peak power always occurs at 50% efficiency no matter how low you set the current limit....

That's not correct. The maximum power of a motor without regard to current limits is when peak power occurs at 50% efficiency. It's a point of interest for sure, but really only useful to a drag racer. It's going to be a moving target as you heat up the stator. I wouldn't be surprised if while it was really hot like you guys were running that max power would be 20-30% lower than a run starting with a cold motor.

As an example of a motor being well above 50% at peak power using current limiting, a 72V pack sagging to 69V and a 100A current limit the motor I'm running on my bike right now is 89% efficient at peak power. With the wheel I have on the rim that occurs at 42mph. At 12mph the same current limit makes 184 Nm of torque with efficiency still above 60%. Now that I'm performance spoiled 100A isn't nearly enough with this Kv, and gearing. and even the 200A limit I'm running now isn't enough. While the peak power point must be at lower efficiency it's still plenty efficient since I don't have heat issues running it stock.

Justin's simulator also demonstrates how we don't run our motors where peak power occurs at 50% efficiency.

I don't know much about electronics, but I've got a pretty good handle on hubmotor performance and always make an effort to err on the side of conservatism, which I believe is in the best interest of ESers.

John