75.6km/h, 47mph

[Lowell]

I put a lower fairing back on the bike, along with plenty of 200mph tape, and added some foot pegs midway up the seat tube a la Safe
With my feet on the pegs, and a partial tuck I only hit 75.6km/h instead of the intended 80.5.

Unfortunately one of my Powerpoles is damaged. Connector body shows signs of excessive heat and the contacts appear flatter. Vmin dropped to only 69.0v on a fresh pack, 7-8v below normal. Amps on the top end dropped to around 31. The good news is that the bike is much quicker with a lot less power. 2140W input power to go 47mph means the bike should only need 2420W input to hit 50mph, well under what it was making before. Tucked into a ball feels like MUCH less wind resistance as the numbers show, but I don't know how long it would be comfortable to ride like that...

A change to beefier connectors and heavier gauge wire (12ga right now) should reduce some losses but that will have to wait until next week as I'm heading out of town for work. I also have not changed the 26x1.95" knobby out on the rear yet, and if
http://www.kreuzotter.de/english/espeed.htm#
is correct, I'm losing 1mph there.

 

[Lowell]

 

[safe]

Hot Damn!

Well you're equal to me now as far as top speed. You're pulling about the twice the Watts that mine does to do it, but you're there. It's so very tempting to want to make it that last 3 mph to officially make it into the "50 MPH Club" but those last 3 are the hardest.

Good Job! 8)

P.S: I'd like to see how you mounted the foot pegs... (comfort is all about getting the footpegs in the right spot)

 

[safe]

Okay, copied this from over in the "video" area.

You might try moving the foot pegs backwards a couple of inches. They look a little too far forward... not much... but just about 2 inches back should do it. (the other side of the tube) Do your legs feel like they are up in your chest? Do you feel like you have no weight on your hands? By moving the pegs backwards the effect is to shift the weight balance forward and place more weight onto the front wheel and your arms. It will feel better and the handing will be better too.

 

[Lowell]

If the pegs were back a little it would be better, that was the easy place to put them in 5 min

 

[xyster]

Love the round analog ammeter!
Looks much nicer than my square one. The rounds ones I found were all much more expensive.
Safe'll be eating your brake dust in no time. Double power should easily beat gears!

(since I'm not about to try for 50mph, it's up to you to carry the Hubmotors-Rule top speed torch )

 

[Lowell]

Actually that meter was only C$16 at a local auto parts store. The electronics store I checked wanted $20 for a 50 amp panel meter and I would have to make my own mount for it. This automotive gauge has a 12v light inside (unused so far) for easy viewing at night.

Hub motors have pluses and minuses. If I could have multi gears with the same noise level (which is pretty much nil) and reliability I would be all for it. It would be nice to have an 8 speed reduction set integrated into an X5 power plant for doing wheelies...

 

[Toorbough ULL-Zeveigh]

If you haven't done so already, might I suggest bar endz to help shift the weight forward, or even better, aero bars (haven't tried those yet). Ever since I transferred my old Onza's to my ebike I can now feel the front suspension actually doing something, now that it has some weight over it. With their large hook region, it's almost like having a 2nd forward bar. It defiantly feels more balanced & secure & is my preferred riding position. Gets you lower out of the wind too, your less like a parachute.

 

[Lowell]

I actually took the bar ends off this bike as I would never use them at high speeds since you can't reach the brake levers. I also ruled out aero bars as I would have to reconfigure too many things and it's not how I want to ride on the street. Maybe on a dedicated speed machine that's only ridden on sunny days, and open roads with no traffic.

 

[safe]

Safe'll be eating your brake dust in no time. Double power should easily beat gears!

Since my "little" 750 Watt bike gets me to 47 mph my next one at 1200 Watts is supposed to be nipping on the edges of 60 mph. By then you'll need something like 90 Volts to keep up.

Whatever a single speed can do (hub motor) a multispeed will always do better...

 

[Lowell]

Better can mean many things. All things being equal, two different powerplants that put the same number of watts to the road will go the same speed. While I was stopped on the side of the road checking speed controller temps last night, a cop car drove up, slowed down and they checked out the bike as they drove by. I'm sure if I was on some motorcycle looking contraption without a license plate they would have stopped...

 

[safe]

All things being equal, two different powerplants that put the same number of watts to the road will go the same speed.

This is NOT TRUE.

With gearing you can set your "peak power" to coincide with your "ideal speed". Unless you are careful to EXACTLY match those two things then you will not get the most out of the hub motor. (as far as top speed)

Plus, you always have two things:

1. Top speed (needs a high gear)

2. Hill Climbing (needs a low gear)

If you try to climb a hill in high gear you waste huge amounts of power and if you try to reach top speed in a low gear you simply can't.

Gears are always better than fixed... except some people are concerned about maintenance of a chain, but I don't see it as a huge problem... chains are pretty reliable things...

This is really a "recap' of the "Great Hub Motor Debate" that poor Xyster had to confess was a complete and absolute victory for my side. But I'm a gracious winner... and I never brag. (this ought to yank Xysters chain!)

Actually... if you could run REALLY high voltage and then restrict the heck out of the amps you might get a "perfect" machine that would actually beat the gearing options. 120 Volts? 200 Volts? That might do it... so good old "brute force" and high voltage would work. (that's some scary voltages to deal with though)

 

[xyster]

... and I never brag. (this ought to yank Xysters chain!)

Better hope we never meet up at an EV event. I'll yank your chain for a change, right off your bike before we race

 

[Matt Gruber]

Hi Lowell
i dug up an ammeter 60-0-60 similar to yours. unused from the 70's.
Hooked it to my halogen tester and at 30a it had a 30mv voltage drop, thats good! But mine is hard to read under 30a so back in the box it goes.

 

[lemmiwinks]

Am I the only one who'd like to see a photo or two of the faring on the bike?

 

[lemmiwinks]

Never mind! Found it in the other thread.

 

[Lowell]

All things being equal, two different powerplants that put the same number of watts to the road will go the same speed.

This is NOT TRUE.

With gearing you can set your "peak power" to coincide with your "ideal speed". Unless you are careful to EXACTLY match those two things then you will not get the most out of the hub motor. (as far as top speed)

Plus, you always have two things:

1. Top speed (needs a high gear)

2. Hill Climbing (needs a low gear)

If you try to climb a hill in high gear you waste huge amounts of power and if you try to reach top speed in a low gear you simply can't.

Gears are always better than fixed... except some people are concerned about maintenance of a chain, but I don't see it as a huge problem... chains are pretty reliable things...

This is really a "recap' of the "Great Hub Motor Debate" that poor Xyster had to confess was a complete and absolute victory for my side. But I'm a gracious winner... and I never brag. (this ought to yank Xysters chain!)

Actually... if you could run REALLY high voltage and then restrict the heck out of the amps you might get a "perfect" machine that would actually beat the gearing options. 120 Volts? 200 Volts? That might do it... so good old "brute force" and high voltage would work. (that's some scary voltages to deal with though)

My initial statement is still correct. "Put the same number of watts to the road" and "will go the same speed"

Let me make it more clear. The same number of N force/thrust.

 

[xyster]

My initial statement is still correct. "Put the same number of watts to the road" and "will go the same speed"

Let me make it more clear. The same number of N force/thrust.

Agreed. Except I think the phrase should be "can go the same speed" instead of "will go the same speed". The same peak thrust could occur at different rpm's. But that peak thrust sets a ceiling on top speed that changes to gearing can not raise.

 

[Lowell]

My initial statement is still correct. "Put the same number of watts to the road" and "will go the same speed"

Let me make it more clear. The same number of N force/thrust.

Agreed. Except I think the phrase should be "can go the same speed" instead of "will go the same speed". The same peak thrust could occur at different rpm's. But that peak thrust sets a ceiling on top speed that changes to gearing can not raise.

Then there would be a different number of watts to the road if the gearing or motor wind was not optimal.

 

[Lowell]

Safe'll be eating your brake dust in no time. Double power should easily beat gears!

Since my "little" 750 Watt bike gets me to 47 mph my next one at 1200 Watts is supposed to be nipping on the edges of 60 mph. By then you'll need something like 90 Volts to keep up.

Whatever a single speed can do (hub motor) a multispeed will always do better...

I have a fifty pack of 4110 MOSFETs on the way. Hopefully they'll be waiting for me at home when I get back from my work trip. Justin at Ebikes.ca gave me a few speed controller tips that I'm going to implement, such as adding copper braid to the FET bus. I'm going to overbuild the electricals this time using at least 75 amp connectors and turn the amps to the max.
I'm still trying to decide how to implement a voltage boost (turbo?) under load, but still keeping the no load voltage under 105v. There was mention of 70 amps being the point where the solder starts melting around the MOSFETs, but this shouldn't be a problem with the extra heat sinks and ram air cooling I've set up. Should be interesting to see how many watts the X5 hub can handle before I need to machine vents into the side covers to pump air through it.

 

[xyster]

Should be interesting to see how many watts the X5 hub can handle before I need to machine vents into the side covers to pump air through it.

Yes, yes, very interesting! Compared to this, Safe, gears are bore-rrring! Gears are like, 'been there, done that' for centuries. This is new territory!

Do you have a way to check or record the motor and controller's temperature?

You mentioned 105 volts. Are you swapping other components for higher voltage versions? Was 105 volts the voltage Justin thought the controller could handle?

That'd be quite a trick, pumping air through a hubmotor. Could poke holes in both covers to let air passively blow through. But that'd of course open it up to junk gumming up the innards. Hard to imagine packing our hubmotor in ice either...I can just see the baggies breaking and ice cubes flying up from behind the bike like a rooster tail of water behind a jet boat If you're like ypedal-buzzz, you'd down a few brews and take a buddy asphalt skiing behind the machine.

Then there would be a different number of watts to the road if the gearing or motor wind was not optimal.

You could be right. This is hard for me to visualize, but it's the reason I thought power would act as a flat ceiling to speed: imagine an ideal system optimized with gears and motor wind for top speed possible. Now increase the gearing ratio so that'd it go faster if it had additional power. Won't the motor slow down a little as a torque goes up and voltage droops under load? Wouldn't efficiency decrease (since we're measuring power to the pavement, not power from the batteries)? Could the product of torque and voltage and efficiency not be the same at some points as in the idealized system? I noticed you switched the argument from power to torque/thrust. Is this why? Torque is independent of wheel size, but thrust is not. As wheel size would be akin to gearing, if there's a singular peak and not a flat-ish ceiling, seems to me it'd be on the thrust measurement curve, not torque or power.
I know this argument deviates a little from my earlier statements -- my understanding is evolving. My mental grip on the notions of torque and thrust has always been rather tenuous anyway.

 

[Leeps]

Lowell be careful with the mosfets, the pins on the T0-220 case is the limiting factor on high power mosfets, theyre rated to 75 amps. 70 amps would be too close for my comfort. The nice thing with having a mosfet rated to 100 or so odd amps in a package thats rated to 75 is that you dont have to derate the device until it gets past a certain temperature. A mosfet rated at 75 amps gets derated the moment its temperature rises, a high power bad boy gets to keep its 75 amp rating up until it burns you, check out the datasheet for specific points.
Joe

 

[fechter]

The FETs are in pairs, so the package limitation would be 140 amps.
105v would be over the limit, though.

The stock shunt will likely melt at 100 amps, so it will need to be beefed up.

Go for it!

The copper braid is a good idea. You could also just use pieces of heavy wire.

When I did mine, I also replaced the heat shrink that insulates the FET mounting screws, since the stock stuff looked pretty thin.

Tip: (you probably already know this) Mount all the FETs on the heatsink before you start soldering them in. This way all the holes will line up. Do the parts side first, then unscrew the heatsink to do the bottom.

Also test each FET screw for continuity to the power leads when finished to make sure everything is still isolated.

Guess I need to get that adjustable limiter circuit dialed in.

 

[Lowell]

Should be interesting to see how many watts the X5 hub can handle before I need to machine vents into the side covers to pump air through it.

Yes, yes, very interesting! Compared to this, Safe, gears are bore-rrring! Gears are like, 'been there, done that' for centuries. This is new territory!

Do you have a way to check or record the motor and controller's temperature?

You mentioned 105 volts. Are you swapping other components for higher voltage versions? Was 105 volts the voltage Justin thought the controller could handle?

That'd be quite a trick, pumping air through a hubmotor. Could poke holes in both covers to let air passively blow through. But that'd of course open it up to junk gumming up the innards. Hard to imagine packing our hubmotor in ice either...I can just see the baggies breaking and ice cubes flying up from behind the bike like a rooster tail of water behind a jet boat If you're like ypedal-buzzz, you'd down a few brews and take a buddy asphalt skiing behind the machine.

Then there would be a different number of watts to the road if the gearing or motor wind was not optimal.

You could be right. This is hard for me to visualize, but it's the reason I thought power would act as a flat ceiling to speed: imagine an ideal system optimized with gears and motor wind for top speed possible. Now increase the gearing ratio so that'd it go faster if it had additional power. Won't the motor slow down a little as a torque goes up and voltage droops under load? Wouldn't efficiency decrease (since we're measuring power to the pavement, not power from the batteries)? Could the product of torque and voltage and efficiency not be the same at some points as in the idealized system? I noticed you switched the argument from power to torque/thrust. Is this why? Torque is independent of wheel size, but thrust is not. As wheel size would be akin to gearing, if there's a singular peak and not a flat-ish ceiling, seems to me it'd be on the thrust measurement curve, not torque or power.
I know this argument deviates a little from my earlier statements -- my understanding is evolving. My mental grip on the notions of torque and thrust has always been rather tenuous anyway.

What I was thinking for cooling the hub motor was vents on each side, but facing in opposite directions such that one side will tend to pump air in with wheel rotation, and the other side will extract. Dirt filters will keep road grime out and the aero losses should be negligible at 5000+W.

If two bikes put out X watts to the rear wheel at 50mph, they will have the same thrust. Torque would of course depend on wheel size. I think my original point was that it takes a certain amount of power to go Y mph, regardless of how it arrives at the road.