Crytalyte 2016 Crown Hub Speed Problem??

[Johnuhtron20]

Hello all,

I'm new to this forum and sort of new to electric bikes. I have a question about my new hub motor, it doesn't seem as fast as it should be??

I have recently purchased the latest 7000 watt Crystalyte Crown hub (96v 85kph wind) on a 26" rim with a crazy bob 2.5" wide tyre.

I have it powered with a 96v 75 amp Crystalyte controller and 4 x Multistar 16ah 6s Li-poly batteries rated at 10c discharge rate, linked in series. So that's 100.2 volts fully charged with a continuous output capability of 160 amps from the batteries and 320 amps burst.

So far it runs nicely, it accelerates like a bullet being shot out of a gun! With respect to its acceleration it is brilliant!!

However I top out at around 43 mph, which is still pretty fun on a push bike! However it does say 85kph wind, which is 53 mph.

So my question is simple, is it supposed to go 53mph?? or is that just a measurement figure to state what winding the motor has rather than an actual real world speed that you would get from the hub?? If its supposed to go quicker, then is there any suggestions as to how I might rectify the problem if there is one?

Thanks in advance for any advice or information

John

 

[Jon NCal]

Perhaps check the 3 speed switch?

 

[wesnewell]

First off the TC motor is not rated at 7000W. It's approx. 2600W rated. There are 2 different 40mm magnet versions, the tc4080 and the tc40100. On 100V 75A the tc4080 tops out at 78.8kph on the simulator and overheats in 19 minutes with ~4100W. The tc100 tops out at 87.6kph and overheats in 9.2 minutes with ~5600W. The tc3080 tops out at 84.3kph and overheats in 6.5 minutes with ~5000W. If the seller rated it for 7000W, there's no telling which motor you got, but I wouldn't be surprised if he sold you the tc3080, which would have a standard rating of ~1500W, to which he used a peak rating of 7000W to fool the ignorant.
http://www.ebikes.ca/tools/simulator.html

 

[amberwolf]

You might want to go to http://ebikes.com/simulator and play wiht various settings to see what you should be getting. If they dont have your specific motor, there is probably one close to it.

 

[Drunkskunk]

Who was the vendor? The Crown is in no way a 7000w motor. it can hit 7000w for a few seconds fine, but would overheat and melt swiftly if run at that power for long. Crystalyte doesn't list a wattage for the motor. Here's the specs from Crystalyte's website: http://www.crystalyte.com/The Crown.htm

If the vendor was the kind to list the motor by it's peak wattage, then they are probably the kind to list it by it's peak speed with the wheel held off the ground. Your actual top speed will be lower. Usually 20% or so. in other words, just about where yours is.

 

[dogman dan]

Bingo. the vendor sold based on the no load speed of the wheel. The tire off the ground spinning in air.

FWIW, at full gallop, you won't be drawing all 7000w, so the overheat thing may not be all that big a deal, unless you are riding up a twisty mountain road.

Not sure what your wattage would be at 43 mph, around 3000w?

Even more volts would make it top out faster, at risk of melting it. At 53mph, the continuous wattage would be higher, 4000w by the sim I suppose.

The sim should tell you what the wattage will be at 43 mph, with your weight, on any grade. The overheat time should be slightly longer, due to the wind helping cool the motor some.

 

[johnnyz]

I have read all the replies mostly from people who have no practical experience.

I have this trike that I made myself. It has a 92 volt system using a crystalyte 18 fet controller pulling a max of 65 amps so around 5200 watts. The motor is an H4080 connected to a 24 inch wheel..

It pulls very good up to 65 kph..then slows down for a top speed of 75 KPH of so...or so...depends greatly on a number of factors that the ebike simulator fails to take into consideration. Like Aerodynamics which most people under estimate...wind speed..the prevailing winds at the time your driving your bike..grade...weight of bike plus rider..

FACT: IF it takes 1000 watts to MAINTAIN 40 kph then to DOUBLE the speed to 80 kph would require 4000 watts...and thats just to maintain the speed...accelerating at anywhere near your theoretical or real top speed is going to be non-existent the closer you get to that limit..ALSO, at or near that limit it would take very little to start scrubbing off your speed, like a 5 mph wind or 2 degree grade. The ebike simulator does not reflect real world conditions. For example, it says on a recumbent trike that it should only take 150 watts to maintain 32 kph...I laughed when I read this...its completely erroneous...real world test reveals anywhere from 200-800 watts...that is when im driving on a relatively flat road with normal winds here in London Ontario the watt meter will wildly fluctuate between these values many many times every couple of seconds.

It also reports motor over heating given a set of amps pulled through the motor. Again, these are actually erroneous values based on the motor on a stand not counting the wind that would be hitting the hub side plates adding a cooling effect on the vehicle itself. I have driven the trike hard..and on a 90 degree day after 30mins of brutal riding the motor is still alive (after 3000 kms)...hot yes, but it didnt blow up, didnt melt, etc.

Now take a bike that has the Aerodynamic equivalent of a brick, and a couple of things will happen...your speed because your pushing alot of wind, will require more power to get to the speed you want and as a result the motor will heat up more.

Theres a reason why the Guinness book of records had for the longest time, the record for the fastest sub 100 lb ebike at something like 65 MPH. Why?...cause it's damn hard to do!.

John

 

[ulrichw]

[...]
FACT: IF it takes 1000 watts to MAINTAIN 40 kph then to DOUBLE the speed to 80 kph would require 4000 watts...
[...]

It's actually even worse than that. The power to overcome aerodynamic drag goes up as the *cube* of the speed. (The force is what goes up as the square).

Therefore, doubling the speed increases the power needed to overcome drag by a factor of 8, not 4. (Note that there are other sources of drag, but most of these become irrelevant at higher speeds (starting around 40kph, which I believe may be why you selected that speed) as aerodynamic drag dominates)

 

[johnnyz]

[...]
FACT: IF it takes 1000 watts to MAINTAIN 40 kph then to DOUBLE the speed to 80 kph would require 4000 watts...
[...]

It's actually even worse than that. The power to overcome aerodynamic drag goes up as the *cube* of the speed. (The force is what goes up as the square).

Therefore, doubling the speed increases the power needed to overcome drag by a factor of 8, not 4. (Note that there are other sources of drag, but most of these become irrelevant at higher speeds (starting around 40kph, which I believe may be why you selected that speed) as aerodynamic drag dominates)

Yes, that is why I used that speed as an example..I think people get the wrong idea because they get in their cars and think nothing of going down the highway at 70-80 mph...but most cars have at least 200 hp and if you divide that into the weight of an average car (3600/200) you would get a HP to weight Ratio of about 18. If I were to take my trike for example at 120 lbs plus me=295 lbs / 5300 watts max..(7 hp)=42. so...the car is 2.3 times more powerful and able to speed through the wind not to mention the car is more aerodynamic and you can see that in reality most ebikes, trikes are underpowered even though it feels like its a rocket..lol...in order to have the same power to weight I would need to push about 12000 watts or 16 HP and that is really tough to do on a hub motor not to mention no battery designed to fit in the parameters of an ebike or trike could fit to produce this much power.! and you still have to factor in the added disadvantage of being aerodynamically worse.

 

[Johnuhtron20]

Hi guys and thanks for all your info and comments. The vendor was ebikes in California. They said it was there latest hub. It looks a lot like the tc80/100 accept it is ventilated, has venting holes around the sides of the hub. My speed controller is a 75 amp 24 fet 96v crystalyte controller. Today I road 14 miles at an average speed of 26mph, took about 25 minutes..ish and used 9.5 amps off each of my 4 x 6s lipo packs. I gunned it basically. The hub was hot but not to the point of it being dangerous.

Lots of people have said it wont run at 7kw and that is the peak power output. Perhaps that is correct? not really sure, but I am in the middle of getting hold of a decent power measurement system to measure the power draw.

I put an image of the hub on here, perhaps someone can identify it?

 

[johnnyz]

Hi guys and thanks for all your info and comments. The vendor was ebikes in California. They said it was there latest hub. It looks a lot like the tc80/100 accept it is ventilated, has venting holes around the sides of the hub. My speed controller is a 75 amp 24 fet 96v crystalyte controller. Today I road 14 miles at an average speed of 26mph, took about 25 minutes..ish and used 9.5 amps off each of my 4 x 6s lipo packs. I gunned it basically. The hub was hot but not to the point of it being dangerous.

Lots of people have said it wont run at 7kw and that is the peak power output. Perhaps that is correct? not really sure, but I am in the middle of getting hold of a decent power measurement system to measure the power draw.

I put an image of the hub on here, perhaps someone can identify it?

I think you answered your own question..lol..

Besides pumping lots of AMPS through a hub motor the other enemy is heat. Heat...ambient heat...there is a huge difference gunning your hub motor in 90 degree heat vs doing it in 50 degree weather. The side panels are Aluminum. Aluminum absorbs heat, FAST. The color black is the worst color for painting a Hub motor because it will heat up with the sun shining down on it 5 times as much if it were white for example. There's a reason they NEVER paint travel trailers black and almost always are white.

I can say based on your figures that its a hungry motor..looks to me like you were using at least 38 wh per K maybe more

So yes especially given that the motor is vented, it can handle 7000 watts. Remember even though your "gunning it" it wont stay at maximum amperage for very long anyway...the only way that would happen is if you spent 25 minuets wide open on a steep hill...and who ever does that to a hub motor deserves 10 lashes..

This is the Crown Motor by Crystalyte. Im not sure of the wind of this motor, but depending on this important factor, it may be wound more for torque than speed.

 

[Johnuhtron20]

Yeah it does get hot, but doesn't get any hotter than what it did. I sat at full throttle for a portion of the journey for 5 min at 42 mph flat out, even when going up hills it barely dropped maybe by 1 or 2 mph for a few seconds. The rest was accelerate hard/ brake for the rest of the journey.

Yes the motor can be hungry as I noticed!!, and yes it is a 85kph wind motor not the 100 kph or 120 kph that was offered. I just thought it might do 85kph, but am happy with it either way, it accelerates quite hard. 0 - 30 mph is 5 seconds and that was going slightly up hill without peddling, i got a video of it with speedo earlier hehe!!

 

[johnnyz]

Yeah it does get hot, but doesn't get any hotter than what it did. I sat at full throttle for a portion of the journey for 5 min at 42 mph flat out, even when going up hills it barely dropped maybe by 1 or 2 mph for a few seconds. The rest was accelerate hard/ brake for the rest of the journey.

Yes the motor can be hungry as I noticed!!, and yes it is a 85kph wind motor not the 100 kph or 120 kph that was offered. I just thought it might do 85kph, but am happy with it either way, it accelerates quite hard. 0 - 30 mph is 5 seconds and that was going slightly up hill without peddling, i got a video of it with speedo earlier hehe!!

Thats funny...but I have and can make a video of my trike doing 0-50 kph in 5 seconds!...top speed of about 47 MPH or 75 KPH...your motor unfortunately has to fight greater air resistance than I do...when I got my bike I couldnt believe the aerodynamic drag going just 55 KPH

Compared to my trike at 75 KPH...just no comparison!..


I just might be putting her up for sale...