ebike4healthandfitness
100 kW
- Joined
- May 19, 2012
- Messages
- 1,283
Nah GaN fets are lame, what you want for really high temps is SiC FETs.
Yeah sure dude. Like I would really trust your opinion over MIT's.
Nah GaN fets are lame, what you want for really high temps is SiC FETs.
Thanks, what controller do you use for the BBSHD? I know this is possible but the simpler solutions are a bit expensive (for running HD at 72v).Just a couple notes....
A. You can run a BBSHD on 72v with an aftermarket controller...I did it.
B. Torque output for different motor windings...for the same BATTERY amperage, all windings of a given motor design (Leaf motor for example) will produce the same torque. The difference is in the phase amperage required...a fast wound motor (Leaf 3T for example) will require more PHASE amperage to output the same torque as a slow wound motor (Leaf 6T for example).
To be a little clearer...if your controller is capable of putting out enough PHASE amperage, the torque output of a given motor design like the Leaf motor for example is the same for all windings i.e. 4T, 5T, 6T, etc. assuming you feed them the same power i.e. Volts X BATTERY amperage.
The terms "Torque Winding" and "Speed Winding" for a given motor design are misnomers.
Leaf sent an email saying the motor phase wires can’t handle 3000w-4000w or 60a-80a. Any idea if this is true in practice?
It was a joke, I was in fact making fun of you for reading a few things about new semiconductor technology and thinking it's so easy to just throw them in anything and it will magically solve all your problems. Both SiC and GaN FETs do perform better at higher temperatures SiC probably slightly better but they are both new technologies that have pros and cons and require considerable skill to design controllers to use them at these high power levels.Yeah sure dude. Like I would really trust your opinion over MIT's.
No doubt the wires get really hot and torque output is not anywhere where it should be compared to if the phase wires were sized appropriately. But see....nobody ever gets actual dyno results at these elevated power levels so we will never know exactly how bad the situation is. Leaf knows though.
Yes, you said that but you also added the fast winding needs more phase amps:
Post #3418:
But as you know there is a limit to the amount of phase amps that can be supplied. So while what you say is true in theory it is not true in practice because of controller and phase wire limitations.
Speaking of aftermarket BBDHD with 72v which you also mention in your post above I see Luna cycles made a tiny 72v 100 amp controller fit inside the little BBSHD shell using nothing more than silicon based fets:
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Luna BBSHD Ludicrous V2 Released!
The Ludicrous V2 is the result of many months of R&D designing a motor controller from scratch with the latest innovations in motor control, spanning over 100,000 lines of code, the best automotive qualified materials, and vastly proven building blocks; all tightly integrated into the stock...lunacycle.com
So yeah, I don't see what the big deal is for putting a controller inside a much bigger DD hub motor is. This especially with statorade cooling and GaN FETs. Anyone building a high end DD hub motor should be able to do this.
I would happily dyno my bike if you want to pay for it. So as a gross oversimplification lets just see how much power is wasted in my phase wires. Leaf motor, 200 phase amps, 10ga wires. Lets say there is about 6in of wire since it switches to larger wires right outside the shaft. That would be 60 watts of loss which seems pretty negibale at the 8Kw I'm forcing into the motor and seems pretty small comapred to the probably 1kw at least of heat being dissipated in the motor. And that is at absolute max torque which can't even be used for very much of any given ride.
I don't think any real world experience anyone has had with the leafbike is going to matter to you, ebikes4healthandfitness.
It's an unproductive discussion at this point.
This is the second time you came in this thread and filled it with pages of non productive arguments about various things that aren't leafbike 1.5kw, and refused to admit the points you were wrong on.
I've told you to stop doing so before yet you are doin' the same thing.
Stop, and leave this thread.
refuse to accept points people make based on real world experience.
Yes it does which is why I replaced them with 10ga which is quite easy to do.First of all the Leaf 1500w phase wires are 12 gauge, not 10 gauge.
Secondly at peak torque if you are putting in 8K into the motor you will be dissipating far more than "probably 1kw at least of heat". You should have instead wrote "probably 7kw at least of heat"
Anyway, I made a point earlier in the thread about the trend for higher 0 rpm torque in various motor systems and EVs. Trying to get that same level of performance out of leaf 35mm wide stator is very likely impossible. Certainly your 200 phase amps won't do it.
True Ghost pedaling.Yes it does which is why I replaced them with 10ga which is quite easy to do.
Oh so I guess we totally agree, discussion over. 200 PA is already well well into diminishing returns and while the controller is set to that it's rarely used but at that level the phase wires are not at all the limiting factor so putting the controller inside would solve nothing. That's the point I'm trying to make, I don't disagree that other motors are better at providing torque at 0 RPM and the Leaf will only do so much, it's not even very efficient at that since it's a hub motor but is has plenty for it's application. In fact my other bike is designed for zero RPM torque to the point I had to gear it up a bit because it was more torque than was possible to use. The reason the bikes are designed like such is because the Leaf spends very little time at low speeds and the LR bike spends all of it's time at low speeds.
To get this thread back on topic here is my still has some things to do but done enough for now Leak bike:
View attachment 363851
I messaged leaf asking what the kv rating is for the 3t and 4t 1500w motor. The response I got was
16.7
14.2
So I'm a bit confused. Has anyone ordered one of these motors recently and able to confirm either of these numbers?
Since that article was written Leaf has changed the Kv values. This change in Kv for 4T was even confirmed by Kuromaku:
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Leaf / leafmotor / leafbike high efficiency 1500w motor
Charge to a lower percentage than 100%. Problem solved. Actually I think he was concerned that the battery would gain too much charge on the long descent. So even if charged sub maximum (at beginning of the descent) the fear is at some point the battery will reach fully charged before getting...endless-sphere.com
I hadn't seen this last post before^. If indeed the newer winds are slower than a couple of years back, then the 4t being around 12.5 now makes more sense than it being 14.2 as leaf told me via email. I suppose i could always email them again and see if i get a different answer. I'll probably end up ordering a 4t anyway, but it would be nice to know for sure which numbers are currently correct for the different windings.Some early data from a Leaf "1500W" ordered in early April, 2024:
Config: 35H, "4T," prelaced into an 80mm 406 rim, 170mm dropout fitment, cassette option
Mass: 10.74kg (with spokes, rim, 60cm motor cable, preterminated with ring lugs and a rectangular Hall connector)
Axle: 225mm length, 85mm CL-to-shoulder on both sides, M14-2.0 threads on cassette side, M16-2.0 threads on the brake disc/cable side
Phase wiring: consistent with 4mm² cross sectional area
Ls, LCR bridge @10kHz, 1Vrms: 81µH (with ~60cm phase wiring)
Ls, Baserunner, 50.0V bench supply: 83µH (with ~60cm phase wiring)
Rs, 10Adc @ 23°C: 43.5mΩ (with ~60cm phase wiring)
Rs, Baserunner, 50.0V bench supply : 47mΩ (with ~60cm phase wiring)
KV, 50.0V supply on homebuilt trap controller: 12.5rpm/V
KV, Baserunner, 50.0V bench supply: 12.27rpm/V
so apparently now 12.5kv is the 'faster hand-wound version' of the 4t? and if the machine-wound is 50rpm slower that would make it around 11.5kv?There are two kinds of 4T.
One was made by machine. The other was made by hand.
Made by hand is about 50rpm faster than made by machine.
Also, the same 4T, the same made by hand or by machine. Also, about 20 ~ 30 rpm difference.
Also, the same 4T, work with square controller and sine wave controller, they are different speed. Square wave is about 50 rpm faster than sine wave controller.
** The fastest 4T is made by hand and work with square wave controller. About 12.5kv @48v
If full charged battery, work with 48v or 52v battery, they are different speed.
Don't get too caught up in getting the exact Kv value because it can vary a little bit depending on the conditions while you are testing....i.e. Controller Type, Voltage you feed it, Any load whatsoever, etc.well this is the response i got:
so apparently now 12.5kv is the 'faster hand-wound version' of the 4t? and if the machine-wound is 50rpm slower that would make it around 11.5kv?
maybe he mixed it up and 12.5kv is the machine-wound. not sure why it's so hard to get a simple answer, i'm sure they waste so much time answering these kind of questions.
I'm not looking for perfectly exact, it's more that in the last few email exchanges with them he has effectively told me the 4t is anywhere from 11.5 and 14.2(?!) which is quite a wide spread. I've established that the 5t will be too slow and the 3t too fast for what i'm looking for, but it would still be nice to know whether to specify the machine-wound 4t or the hand wound version on the order. I just got the feeling that maybe the 12.1-12.5kv wind people have been offered by them might be the machine-wound and the original 13kv the hand-wound.Don't get too caught up in getting the exact Kv value because it can vary a little bit depending on the conditions while you are testing....i.e. Controller Type, Voltage you feed it, Any load whatsoever, etc.
If you buy a 4T, you may have to run Statorade and Heat Sinks to keep it cool enough. Anything faster than a 4T and you will most likely have overheating issues if you run it wide open for a long time on i.e. "Continuous".
I put my 4T in a 24" wheel and I run a Schwalbe Pick-Up 24x2.6 tire...that is about as fast as the Leaf can go continuously without getting too hot and that correlates to 37-38 mph with a 52v battery on flat ground...and yes I am running Statorade and Heat Sinks. I have to tell you, once you get over about 30 mph, the power required goes up a lot so you'll need a substantial controller and battery if you want to go fast for very long.
You can use the Grin Tech Motor Simulator to get an idea of your top speed and the power requirements...and if you substitute a Crystallite H35xx with the appropriate speed, you can get a good idea what your temperatures are going to do.
Gotcha...sounds like you know a lot more about what is going on than I initially thoughtI'm not looking for perfectly exact, it's more that in the last few email exchanges with them he has effectively told me the 4t is anywhere from 11.5 and 14.2(?!) which is quite a wide spread. I've established that the 5t will be too slow and the 3t too fast for what i'm looking for, but it would still be nice to know whether to specify the machine-wound 4t or the hand wound version on the order. I just got the feeling that maybe the 12.1-12.5kv wind people have been offered by them might be the machine-wound and the original 13kv the hand-wound.
I currently run a mxus 3k in a 19" rim with 2.75 tyres. The 3t mxus 3k is already fast enough for me at 11.9kv 52v, but i don't want to get any slower than that. It's a fun motor, but i miss pedalling and want a cassette with an 11t cog like i have on my gdr19, hence my interest in the leaf.
I asked and was told that the 4t hand wound motor would achieve around 65km/h with a 26” wheel and 80kg rider, with a battery at 52.1v. That sounds good but I question whether he actually meant at 58.1v (a 52v battery fully charged is 58,1v, not sure why he would have stated 52.1v with the extra .1v).well this is the response i got:
so apparently now 12.5kv is the 'faster hand-wound version' of the 4t? and if the machine-wound is 50rpm slower that would make it around 11.5kv?
maybe he mixed it up and 12.5kv is the machine-wound. not sure why it's so hard to get a simple answer, i'm sure they waste so much time answering these kind of questions.
Previous reports have shown that the Leaf controllers are nothing great, does anyone know if that has changed?This 18FET controller from leaf
The majority of controllers currently on their site appear to be KT square wave (based on the serial numbers on the labels in the pics). KT places its labels on the top of the case. The linked controller, as well as one other 1000W model, have the label on the end of the case. If they are a common brand (not generic), then the DC Moto Controller brand frequently places the label in that location. Might be similar to the 18FET Ebikeling sells (dual mode, sine wave sensored, square wave sensorless).Previous reports have shown that the Leaf controllers are nothing great, does anyone know if that has changed?