IMPORTANT ANNOUNCEMENT! NEWLY DEVELOPED BMC MOTORS!!!

[dirtdad]

I am not sure which freewheel you are referring to, but the answer is yes in either case. I has a freewheel style, thread on mount for the cassette. And, being a geared motor, it freewheels much better than a direct drive motor. It is no Chris King, mind you, but then what is?

[Mark_A_W]

No, not the freewheel in the screw-on cluster.

An internal freewheel, so you don't spin the motor when you pedal. You can tell by spinning the motor one way - you will feel the gears wind up. Spin it the other way and it will rotate freely - if it has an internal freewheel.

[dirtdad]

...it freewheels much better than a direct drive motor. It is no Chris King, mind you, but then what is?

Yes, what I meant by that is that the motor itself has an internal freewheel.

[fechter]

Finally!

I finally got hold of a few test units! Right now I have the Thunderbolt "600w" rated internally geared hub motor... A few surprises. The factory chose to do away with the steel gears and instead opted for a quieter and much lighter material. The new gears are made of a composite material that is supposed to be much stronger than the previous nylon gears. ...

How about some pictures? What do the gears look like?

[GGoodrum]

Thanks for the updates. I'm looking forward to trying one of the new 1000W motors on the 20" folding bike in my avatar. Right now it has a front-mounted Crystalyte 5303, which works well, but is quite heavy. It is hard to move around/fold.

In the RC world, some of the helicopter manufacturers have used metal-impregnated composite material for the main rotor gear, and these have proved to be quite durable. The problem with metal gears is that metal-on-metal wears out fast. Nylon is too soft. I think these new composite-based gears might be just what is needed to allow lots more power to be put through these without excessive wear.

-- Gary

[hi-powercycles]

Hello Everybody. We had our first test with the Thunderbolt. It turns out it is very fast, but at the same time way more torquey than I expected. It seems to be a hybrid between the Original Thunderbolt announced and the Specs of the Striker. Running with 44.4v Top speed verified with GPS on our weakest controller (25A) was 32 MPH. Acceleration was impressive as well for a 25A system with 0-20MPH in the high 8 second range. Torque was noticeably higher than the 400W motor. On 37V and 25A, top speed was verified at 28 MPH. I am very excited for the tests I have in store for tomorrow! I expect to run with a 51.2v Lifepo4 pack, a 55.5v Lipo Pack, and last but not least a quick speed run with 67v (scary!) I will be using Crystalyte 35A and 40A controllers! I will definately be wearing a helmet and hopefully some padding tomorrow! Will post results!

[solarbbq2003]

Some info on bmc motors, some will already be aware of this info.
Brief rundown: original motor from china factory ( apparantly design development involved ezee company), ezee not so long ago starts getting the motors made from different factory in china ( not bmc but were originally getting from bmc china).
Bmc china motor being sold a few places for a while ( including superkids website........what the??), is sold as a 350watt motor but is actually a 250watt rated motor but 350watt sticks as its rated power. Ananda brand controller is supplied with motor to run on 36v, motor is wound for 36v use.
Teamhybrid call the motor "puma' motor, quite a few problems are identified ( eg keyway needed on axle to stabilise sideways movement), bmc rectifies the problems with input from TH ( and others). Bmc china makes higher power version by changing windings and propose its a 500watt continuous rated motor ( not verified if it is or not). Freewheel mechinism originally designed for 250watt continuous motor, a number of 500watt motors with freewheel mechanism are produced, later bmc china make 500watt version without freewheel mechanism for fear of freewheel failure ( power over its rated specs).
Various controllers used on 350watt ( i.e. 250watt version) at 36volts no problem, at 48v problem identified that higher switching speed controllers needed ( long process and problem identified by "fetch"), various controllers found to be modifiable to run bmc over 48v ( by changing 'crystal', some new controllers are found with higher switching speed chips (infineon, modified v2 & others not posted). Bmc china begin designing 1kw version from scratch to have components rated for higher power use ( including freewheel) release date unknown.
Bmc India plant starts producing 250watt version from some technology transfer from chinese plant. This thread appears anouncing new bmc motor ( i.e. 250watt version from Indian plant being supplied to usa ).
So my view would be there is probably going to be a very similar process happens to the indian made bmc motor that the chinese bmc motor went through ( from what I can gather there is very little communication between china/india plants),
other questions would be are the components in the indian made motors going to be as good as quality as in the chinese made ones.. eg nylon gears in chinese motor sourced in japan. Other issues such as metal used to make side plates quite important ( the threads for gears and disc are inserts), the ring gear quality etc etc. I think these are all unknowns on the indian made motor at present.

LindRch.jpg (61.06 KiB) Viewed 1468 times

[solarbbq2003]

oh forgot most important thing!
bmc solves problem of high torque and high speed in the one motor

[solarbbq2003]

i should mention new problem for 500watt bmc motor from china, under load at higher voltages back emf can exceed 100v when running on 72v sla batts ( not 100% sure on this information is a bit second hand), but could mean 150v fets will be needed for higher voltages ( or damn good caps)

[GGoodrum]

i should mention new problem for 500watt bmc motor from china, under load at higher voltages back emf can exceed 100v when running on 72v sla batts ( not 100% sure on this information is a bit second hand), but could mean 150v fets will be needed for higher voltages ( or damn good caps)

I think the most important feature of the new 1000W model is going to be the composite planetary gears. Nylon would not withstand the extra power, as many have already reported when trying to get more out of the existing BMC/Puma setups, and metal versions will just wear out quickly. Metal-on-metal is never a good idea without active lubrication.

[hi-powercycles]

Good NEWS! We got everything up and running today. We did some baseline testing today with the 600W Thunderbolt vs the old "400W" BMC motor:

*** Keep in mind Acceleration times were done by GPS, and there was a definite lag in the readings, so these times are INFLATED. Real world times are lower. The Acceleration numbers are for comparison only.

{Top Speed, MPH w/GPS} [0-20 MPH Acceleration, Seconds]

400W BMC motor 44.4V Lipo 35A Crystalyte {26.4} [9.24]
600W BMC motor 44.4V Lipo 35A Crystalyte {31.2} [7.58]

400W BMC motor 55.5V Lipo 35A Crystalyte {30.3} [8.42]
600W BMC motor 55.5V Lipo 35A Crystalyte {35.3} [6.81]

Test Notes. We did multiple drag races on flats and up hills. It is interesting to note that the New 600W motors on 44.4v Pretty much performs exactly like the 55.5v system with the 400W motors. The slight edge goes to the 600W on 44.4v. It is slightly faster top speed about 1 MPH or so. Up hills, the 600W with 44.4v would SLOWLY walk by the old 400W motors on 55.5v. Volt for volt, the 600W motor had the definitive advantage and felt like it had more torque as well. An interesting side note, the 600W motor with the new BMC 25A controller on 44.4v went 31.7 MPH and went 0-20 MPH in 9.36. Meaning the top speed is higher than the Crystalyte, and the Acceleration time is similar! I can't wait to test out the new BMC 35/40A controller next week! It should be interesting. Also, I will archive these runs and test out the new 1000W motor hopefully by the end of next week.

[hi-powercycles]

Good day everyone,
We updated the test runs with Thunderbolt 600W! Read the post above!

[snowranger]

Looks good. Can you measure watts, watt-hours? Just wondering if there are any efficiency differences?

[Tom]

New and available now is a "600W" model. Currently rear only, with 36V 25A or 35A controller, or 48V 35A controller.

Anyone know what kind of voltage the 35A BMC controller can handle? I recall reading somewhere the existing 36V/25A BMC controller can only handle up to 45V, but not sure about the 35A. Is 48V the max voltage?

[hi-powercycles]

I know for sure the new 35A controller will handle 51.2v nominal Lifepo4. As far as any higher than that, I will test to make sure when I get them in stock.

[Tom]

I know for sure the new 35A controller will handle 51.2v nominal Lifepo4. As far as any higher than that, I will test to make sure when I get them in stock.

So is the "new" 35A controller different than the existing BMC 35A controller?

[hi-powercycles]

Yes. It is redesigned with much higher internal components. 100v rated FETs. I do not yet know what the voltage cutoff is. When I find out, I will pass on the info!

[solarbbq2003]

this is going to get confusing and difficult to compare motors from indian and chinese factories if the power ratings are made up arbitrarily, a motor will have a given continuous power rating no matter what voltage/current its tested on, calling the motors 400watt and 600watt and 1 kw but not based on a standard way of calculating continuous power rating makes it meaningless when comparing to other motors as its arbritary values ( i.e made up values).
You would have to define how you are getting these power rating values to have any meaning when comparing motors, ultimately how the motor performs is the most important factor.
What are the internal differences between the 400 and 600watt motors? are the windings different in any way?
Its almost certain the motor you are calling 400watt is the same as the chinese version which was called 350watt, but when tested its continuous power rating was in fact 250watt. So your 400watt motor would almost certainly be a 250watt rated motor if it was tested on a torque testing machine ( the graph data can be used to determine the continuous power rating), just using volts and amps isn't enough info to determine continous power rating.
Let me make a guess: your 400watt motor has two strand type windings in it, the other motor your calling 600watt should have a single strand type winding ( but almost certainly wont be 600watt rated more likely 350watt)
Personally I prefer to use max power ratings, the max the motor can handle without burning out if under load for some time, but there are conventions for continuous power ratings, which your not using, so although its nice to say 400watt and 600watt continuous power rated motors it doesn't really mean anything as the values your giving them are arbritary.
If you can give the winding resistances and number of strands in the windings then at least some comparison can be made to the chinese made motors, the point I was trying to make in an eariler post is that these motors are coming from india, based on technology/knowledge transferred from china, chinese have alot of experience with these motors over many years, india its a new thing to make these motors, so comparisons of indian and chinese motors would be quite valuable, other point I was hinting at is that there has been a long difficult process involved with the chinese bmc hub motors, likely a similar process will occur with the indian made ones. If the chinese/indian factories were in very close contact it might not be a problem, but it appears the ties are not very close.

[solarbbq2003]

to get a simple approximation of continuous power rating of a motor you can simply multiply the peak power by 3/16, or around 20% is a rough rule of thumb, to get the a more accurate figure would be complex as depends on alot of variables, but pretty much it means the power you could run the motor at continuously without the windings exceeding a given temperature, power is torque multiply by rpm, so you really need a torque graph to get some idea of the rated power ( continuous power) below shows the area that can be used as approximation of continuous power rating .
I'm no expert on these things but would be interested how you guys are coming up with 400watt and 600watt continuous power on the bmc india motors, can you give resistance values of the windings in the two different motors?

cont power about 20percent peak.jpg (41.8 KiB) Viewed 1700 times

[solarbbq2003]

heres a copy of a test i had done on a 350watt china bmc hub motor using 48v 20amp crystalyte controller
independent test not from bmc

bmc 350watt test data 241007.jpg (142.03 KiB) Viewed 1744 times

The torque testing machine gives a calculation of continuous power rating which came out at 250watt, using 20% of peak power output as rough estimate comes out a bit low in this case.

[solarbbq2003]

another thing of interest from the graph, they design the motor rpm for use on 36v, so in this test the rpm is 420rpm max no load at 48v, this motor was sent as a 320rpm motor. Max efficiency is 77% so they are loosing maybe 7% due to the gears, the motor alone without gears, efficiency would be around 84 or 85%. No load torque was a bit over 40Nm, not too shabby.

[solarbbq2003]

sorry I meant stall torque ( along bottom axis) was a bit over 40Nm.

[hi-powercycles]

Hello to everybody!
I have personally tested and also read all applicable Dyno sheets pertaining to the 400W, and 600W motors.

The 400W geared motor at its peak efficiency (about 78%) outputs 300-420 Watts. Above 420 Watts output, efficiency starts to slowly decline. At 36V and 16 Amps, 19 Newton-Meters of torque are present.

The 600W geared motor at its peak efficiency (about 76%) outputs 650-950 Watts. At this particular dyno testing, we terminated at 950 Watts output, while still in its peak efficiency range. Recently, I tested the motor at 1500W input and still got 1120W output power.... This motor in my opinion is underrated from the factory. On 48v and 26 Amps, 23 Newton- Meters of torque are present. Motor RPMS at peak efficiency are almost 50% higher than the 400W motor!

For those interested in hill climbing torque, the 600W motor is the clear champion because it can handle higher current loads much better than the 400W motor. The 600W motor with the Crystalyte 40A or the new BMC 35A controller would both be killer choices.

I also have preliminary test data on the new 1000W motor. Peak efficiency is about 84%. There are no gears on this one, so we will see how it stacks up against the 400W and 600W geared motors! Motor RPMs at peak efficiency are almost 50% higher than the 600W motor!

I will be conducting more tests early next week, including DIRECT head to head comparisons:
BMC 600W Thunderbolt vs. C-lyte 5304 vs. BMC 1000W (pre production test unit)
Should be fun!

P.S. NONE of these motors are made in the BMC India factory.

[Tom]

I thought the 1000W motor was the third one you described in the original post, i.e. "when you crave the torque to conquer any hill imaginable, then the new BMC striker is your ticket to the top!" If the 1000W has no gears I'd think the 600W would be better choice for hills?

[hi-powercycles]

Hi Tom,
It turns out at the moment, the striker is not available as of right now. I am looking into getting the thunderbolt re-wound for more torque and lower speed. I guess I will have to modify the initial post so that I don't confuse anybody. Thanks for your input