Greyborg Cromotor Hubzilla motors, Sold Out

[gensem]

Its not probably the best hub motor, its the best by a fair margin.
I use 0.1 block time trying to avoid overcurrent but i dont limit current in the CA. Also consider that my power peaks are close to 8kw with 24s lipo.

[hillzofvalp]

If I ran that voltage, I could do 90mph... Right now at 66V I do 45mph.... I will see what I can do with the power. I guess since you're rUnning a higher voltage you have more heating issues... Maybe I can put 10-20% more current iN at this voltage

Update: got my bike up to 48 today. At the end of ride, the motor is pretty warm. 77A/145A setting at 66V nominal. Phase bundle is a little warm after a ride. So much fun.. Sounds awesome too. Horsing around and even going 40-45 for 4 minutes hasn't really effected my efficiency too much. Maybe 7Wh/mile difference during this ride. I need a motorcycle helmet.

There's still a bizarre oscillation... Controller doesn't want to go into full on (no pwm) either. I think I got it to go into full once or twice, but i was going down a slight grade.

So far I've probably put 80 miles on the motor. Soon I will sit down and think how I will do my cooling vents with replaceable caps. This motor will probably get much hotter when I crank up this controller

[hillzofvalp]

If I'm going to push this thing harder, I am tending to lean towards vents. This thing gets hot after a long ride at just 4.5kW in a 29" wheel. Do you approve this message? It's either this or oil...


or to continue large hub motor tradition:

[methods]

When Zombiess runs out of hubs I will have two of the dual-drilled available for pickup in the Bay Area of California (or shipped world wide). Due to a mix-up on my part these two wont be shipped to the original recipient. I will keep them warm for you.

Please buy from Zombiess first if he still has stock - as this is his sales thread and he needs to clear out that inventory so he can order the next batch.

-methods

[hillzofvalp]

I just crossed my data with the simulator on ebikes.ca, and my full speed is about 12% too low in the sim.

[zombiess]

I just crossed my data with the simulator on ebikes.ca, and my full speed is about 12% too low in the sim.

Don't use the Ebikes.CA similar its not even close right now (its overly optomistic on power consumption for sure) Justin hasn't updated it with the info I gave him months ago .probably since he is so busy. Use the info I posted with swbluto sim and Never forget a simi is a sim not real life.

[zombiess]

There's still a bizarre oscillation... Controller doesn't want to go into full on (no pwm) either. I think I got it to go into full once or twice, but i was going down a slight grade.

So far I've probably put 80 miles on the motor. Soon I will sit down and think how I will do my cooling vents with replaceable caps. This motor will probably get much hotter when I crank up this controller

Unplug the CA or set it so it can't limit anything and your oscillation problems will most likely go away.

[neptronix]

That 29" wheel is hurting you, man :/. You're getting a lower power density per given amount of copper and magnet weight in such a large rim. Ever considered going to something with smaller wheels?

After experiencing the madness of a 20" motor, the largest wheel i'd ever put in a hub motor for a performance application would be a 24".

[methods]

After experiencing the madness of a 20" motor, the largest wheel i'd ever put in a hub motor for a performance application would be a 24".

I second that. After doing back to back tests with the same motor in 20" and 26" the mechanical advantage of a smaller wheel is staggering. I love big wheels - but they are just not a good match for direct drive hub motors. Worst of both worlds - lower efficiency, lower thrust, less fun.

Good compromise is a 24" rim with a huge 3" wide tire. You end up around 25", a nice meaty looking tire, and some extra cushion. Hard to fit between a lot of drops though.

-methods

[neptronix]

Oh yeah, i had to shave the vbrake bosses off my Trek hardtail just to fit the 2.75" x 16" pirelli tires on it, even then i was almost rubbing up against the frame

Now i had a magic pie, which is a particularly torquey motor.... but the faster rotation speed meant better cooling and better power per weight. The higher the RPM an electric motor spins, the better. I've seen it in every spec sheet i've looked at - continuous power handling is always higher the faster it is spinning. That's why the little turnigy outrunner motors can put out 2kW and be the size of your fist.. they spin at 5,000-25,000rpm!

Zombiess has his in what, a 20" wheel? and it is amazing what kind of power he's demonstrated so far.

Even a 26" wheel would be an improvement here.

[zombiess]

Dropped the price to $575 for the single motorcycle spoke hole sized motors. JohnRobHolme's can build you a kick butt strong wheel with either kind, but for serious strength and great selection of tires, moped wheels and spokes are the way to go.

[hillzofvalp]

All along I wanted a big 29er. Its very fast the way it is... I'm probably safer, too. Some day I'd like to try it in a smaller wheel.. But that means basically starting all over again with a different frame, and wearing full body protection more often... Just kidding.

I do not know how I arrived at 20S A123 M1 (66V). I guess it was what I could afford at the time and I started with 14S5p, expanded to 20S shortly, and I wasn't about to reassemble for 25s4p.. Which would probably be required to achieve 45mph in such a small wheel.

All in all it's a smooth ride and I think this motor will last me through a series of builds. I think a cargo bike would make an excellent 24" cromotor build if you know what I mean

Edit: I guess it would be pretty inexpensive to relate it into a 24" rim... 39mm wide.. Speed decrease would only be about 15%. I could probably be happy with that.

[hillzofvalp]

TOday after my ride my motor covers were at around 65 degrees centigrade. Is that acceptable?

[methods]

TOday after my ride my motor covers were at around 65 degrees centigrade. Is that acceptable?

You are asking for it - and getting close to getting it.

Try to ride a little more efficiently, lower your wheel diameter, lower your voltage, or improve your cooling. That particular number is fine but you are clearly heating the hub up quite a bit. Problem with that is once the hub is heat soaked it does not take but a few seconds of full power near stall to burn up a weak spot in your winding insulation.

I dont know what your bike looks like (I admit that I did not read this entire thread) but if your bike was my bike I would lower the wheel diameter. Its a win, win, win modification.

If you do manage to blow that Cromotor it wont be because the motor could not handle the power - it will be because you are operating it in an inefficient configuration.

-methods

[hillzofvalp]

I am exploring a smaller wheel, but I'm not thrilled that I will be shifting all the weight of my bike rearward (unless I change the front as well). One day I ran the motor for 4 runs of 12 miles (1 hour between), and I did not get it up to 65C. something about the last rides.. probably 35mph up a grade for 1 minute.. .

So smaller wheel. Okay.. I'll look into it. probably 24" with big tire. My frame is specially made for extremely large wheels, so this will look a bit funny. What about the CNC cover vents with matching lids?

[methods]

Drill holes
Spray water

16oz of water and a simple temperature controller would rock your world. Evaporative cooling is amazingly effective.

Alcohol would be much better but you have to be careful with debonding adhesives. I really cant believe that this is not standard procedure for hubs around here. Guess someone just needs to make it and show everyone. This is pretty much how you do it if you want to be gangster.

A simpler solution is to just drill holes and use some method to get air moving.

-methods

[hillzofvalp]

Here's a silly video I made when I first got the motor and it was raining outside. 70/120A settings.. 66V. Still hauls ass up these ramps in a 29" wheel. Bad cinematography .. I will try to get a real joyride video up.

[zombiess]

I can't believe you have a 29" bike accelerating that fast with a hub motor. Please heed Methods warning. 29" wheels and hard acceleration make for horrible efficiency and over doing it will damage the motor. Even dropping down to a 26" wheel with a road tire would provide you with a big increase in acceleration which would let you reduce the amps some.

[Alan B]

It is all about the efficiency of the motor vs the power you pour in. Just limit power input at low RPM. You'll have to give up some low efficiency acceleration to control the motor heat. The motor is marked 3KW and we've heard that it can handle 4KW continuous, and your dumping perhaps 5KW into it. In a larger wheel the power needs to be reduced because the efficiency is lower due to lower RPM. So lower the power until the motor doesn't get hot. Or cool it. Or melt it and make a video.

[hillzofvalp]

I will be more careful. THis is my baby. We were looking at 4.5kW peaks.. so basically 4.5 kW up to 20mph.

In a couple weeks I'll get a couple thermistors in there and some nice vents. Idk if oil is worth trying...

ALan B, I will try to make a video before it melts.

[Doctorbass]

Drill holes
Spray water

16oz of water and a simple temperature controller would rock your world. Evaporative cooling is amazingly effective.

Alcohol would be much better but you have to be careful with debonding adhesives. I really cant believe that this is not standard procedure for hubs around here. Guess someone just needs to make it and show everyone. This is pretty much how you do it if you want to be gangster.

A simpler solution is to just drill holes and use some method to get air moving.

-methods

Methods,

Evaporative cooling is certainly an easy way to cool down motor, but the problem i see with evaporative cooling is that to be effective, water must evaporate.. so it mean that your motor will be at 100 celsius 212F... or above.. and .. at that temp, the winding resistance is already too high and compromize the performances alot...

also, the non evaporated water will accelrate corrosion on the steel parts from the stator. I think that's why it is not so popular...

But i admit that watercooling too is not so popular due to the complicate level and time required to get it work well. But i gave it a try anyway

Doc

[joe tomten]

Doc says:

"so it mean that your motor will be at 100 celsius 212F... or above."

Nope. Doc. Lick the back of your hand and blow gently on it. Feels cool, doesn't it?

Evaporative cooling at ambient temps.

[methods]

My Arduino temperature-throttle retard system will enable folks to do this pretty easy.
I just need to get off my ass and finish it....

-methods

[liveforphysics]

Fill it about 1/4 way full with oil. Auto tranny fluid. Silicon the side covers on to seal it in. That's going to be the best cooling a hub is going to get that doesn't require boiling water away.

[hillzofvalp]

Fill it about 1/4 way full with oil. Auto tranny fluid. Silicon the side covers on to seal it in. That's going to be the best cooling a hub is going to get that doesn't require boiling water away.

yeah? tested? stray sparks?