Hub motors: Pros and cons?

[CGameProgrammer]

I very recently got my e-bike working, using a Crystalyte 48v motor (#406) on a 700C front wheel, which I assume probably tops out around 38 mph though I haven't measured it. But I've read about people's e-bikes that purport to reach 45-50 mph on even 36v, using geared motors that turn the front gears of the bike (leaving the rear cassette to determine actual wheel speed).

Is that accurate? Are geared motors simply much faster than hub motors? What are the advantages or disadvantages of the two?

I'm having a blast at ~40 mph but more speed would be great.

 

[xyster]

Here's a 27-page Hubmotor V Gears debate :
http://endless-sphere.com/forums/viewtopic.php?t=150

 

[CGameProgrammer]

Ah, that's a large thread. Yet few conclusions seemed to ever be reached... and I don't think anyone talked about reliability or noise. Do geared motors suffer from those? I hate maintenance.

Legality was mentioned, but that's irrelevant because high-power electric bikes are not illegal! They're just not classified as electric bikes.

In the U.S., low-power electric bikes require no driver's license, they can be ridden by 16-year-olds, only a bicycle helmet is required, and they can be ridden on sidewalks and bike paths. But to enjoy these freedoms, they can't be too powerful. If they are, they fall into the classification of 'moped' with a 30-mph max speed limit, no sidewalk driving, driver's license required (I think), and a motorcycle helmet is needed. Beyond 30 mph, they're considered motorcycles and should be registered as such. Technically.

Of course those are arbitrary rules, which is why states are free to override them. Even if they don't, obviously nobody would really consider a pedelec to be a motorcycle, no matter how powerful. But riding 60 mph with a bicycle helmet and no blinkers will draw attention (or death), so it's up to you to act and look like a normal moped/motorcycle rider.

 

[TylerDurden]

Here's one person's take:

Hubs: strong, quiet, more pricey, moderately complex to service, sometimes big & heavy

Gear/chain: gearnoise, small, cheap, 250W-750W, easy to install and service, more maintenance, through-the-gearset drive optional

Etek/Perm/etc.: For electric motorcycles. For bikes and scooters: only psychos need apply.

 

[CGameProgrammer]

Etek/Perm/etc.: For electric motorcycles. For bikes and scooters: only psychos need apply.

OK. Please expand on this for us.

(No I'm not really thinking of replacing my motor already; I'll most likely just go to 72V in a few months.)

 

[Ypedal]

Can't really comment on the chain driven geared setups.. but on the subject of hubs..

Geared and Non-geared hubs... are very different. So are brushed and brushless hubs.

Geared - Brushless hub motors : Check out Paul Knox's and Deecanio's setups.. they have good low rpm torque.. require maintenance once in a while.. and eventually will need new gears, exactly how often is yet to be determined and i would greatly love to hear more on this subject. not as quiet as other hubs.

Direct drive Brushed hub motors - not as efficient as their brushless counterparts, but cheaper . Motor brushes will need to be replaced occasionaly, aprox 6000 km or so ?? you canot severely over-volt them without increasing brush wear.. they create a buzzzzz when they run.

Direct drive Brush-LESS hub motors - not much low speed torque in large diameter rims, but durable, quiet, maintenance-free, can be overvolted up to the controller's limits.. good power in their mid-range speed zone.. great for actual " Pedal Assist " ..

 

[TylerDurden]

Etek/Perm/etc.: For electric motorcycles. For bikes and scooters: only psychos need apply.

OK. Please expand on this for us.

(No I'm not really thinking of replacing my motor already; I'll most likely just go to 72V in a few months.)

Rumor is, one of our comrades, Deafscooter (Craig), did 80mph on this:

This also has an etek powerplant:

8)

 

[fechter]

Don't forget Dave's Insaine-a-cycle:
http://electricrider.com/custom/index.htm

51mph and still accelerating.

 

[Lowell]

Etek/Perm/etc.: For electric motorcycles. For bikes and scooters: only psychos need apply.

OK. Please expand on this for us.

(No I'm not really thinking of replacing my motor already; I'll most likely just go to 72V in a few months.)

Assuming you're already at 48v, consider adding a 36v pack for 84v.

 

[CGameProgrammer]

Well I'd need a new controller, I assume... right now I have what electricrider.com calls the "Crystalyte 4840 controller" (48V 40 amps) though I'm guessing (hoping) it really supports up to 72V, since I don't see a specifically 48V controller on Crystalyte's website. Can someone confirm this?

 

[fechter]

I'd assume that one's good for 72V, but there does seem to be some variation in the models. To be sure, you'd want to open it up and check the numbers on the FETs and capacitors.

The low voltage cutout is set for a 48v pack. If you run a higher voltage, either the LVC will be set too low to protect the pack, or you can add a resistor to the circuit to raise the cutoff voltage.

 

[Ypedal]

I like to run 36-73v controllers on most of my bikes.. leaving the LVC at 29v allows me to run any battery pack i want from my pile..

Simply hook up a DVM or a DrainBrain and monitor voltage visually.

 

[xyster]

Well I'd need a new controller, I assume... right now I have what electricrider.com calls the "Crystalyte 4840 controller" (48V 40 amps) though I'm guessing (hoping) it really supports up to 72V, since I don't see a specifically 48V controller on Crystalyte's website. Can someone confirm this?

Before I bought my 72V35A controller from the poweridestore:
http://www.poweridestore.com/Hub-Motor-Acces/Series-500-Controllers
I asked electricrider if their 48V model wasn't really the same 72V model. He replied that it was not, that the components weren't rated to handle more than 60 volts. My 72V controller was delivered promptly, and handles 84 peak volts just fine. Some people's 72V crystalyte controllers have died at that voltage -- so the quality control is a hit or miss thing. I'd suggest getting yours' from the poweridestore too. The owner, Earl, seems like a good guy and (I assume) would honor the warranty if you got a bum one that dies at 72 volts.

 

[CGameProgrammer]

OK. I too contacted electricrider.com and he said they tested the 72V controllers but didn't find them reliable enough to warrant their approval for sale. Oh well; I'll probably buy it anyway and bring the 48V controller as an emergency backup if it does blow (assuming it won't take the batteries with it).

I don't suppose anyone knows of a more reliable 72V controller? Especially one using the same plugs as the 530X series of motors.

 

[giveahoot]

Great conversation. I was initially considering a gear motor, but was mostly set off by the noise and obtrusiveness. Those two things were just too hard to overcome.

 

[knoxie]

Hi

The 72V xlyte controller is not reliable at 72V, they are using a variety of fets in these xlyte controllers, the only way to ensure they will work ok is to replace the fets with known ones. I have blown 2 controllers at 72V on 2 different motors, one failure took out the BMS in a lipo battery pack it failed so badly.

I would not run 72V on a standard xlyte controller without modification, if it doenst fail straight away it will in time and as we approach warmer climes here in the northern hemisphere this will accelerate.

Ill post the mods I have made to the controller soon assuming it all works, you can upgrade the controller to take 100V 60A reliably for about 70 dollars.

Cheers

Knoxie

 

[CGameProgrammer]

Please do, knoxie. I'm no electrical engineer, but if I can't simply buy a controller that works, I'll attempt to modify the Crystalyte one if you could post instructions.

 

[CGameProgrammer]

Now I'm toying with the notion of trying other motors, just on a test bench for a second bike sometime. I can simply throw more power at my current hub motor, which is a valid strategy, but it seems like most or all of the really fast bikes use high-RPM motors.

thunderstruck-ev.com sells a Mars brushless motor (and appropriate controller) which can reach 4000 rpm with 48V. Then of course there's the PMG 132 or Etek, which are brushed. These would involve a much more difficult installation as I'd have to come up with a mounting platform in addition to a transmission of some sort, but it's tempting. Does anyone have any thoughts on these?

Basically, what is considered the best strategy for increasing speed? Let's assume all roads are nearly level to keep the discussion focused.

 

[xyster]

Basically, what is considered the best strategy for increasing speed?

The simplest, effective strategy is to increase voltage -- particularly for brushless motors that can usually handle much higher-than-rated voltages compared to brushed motors. Wiring more batteries in series is relatively easy, and also increases acceleration and hill climbing power (since power = amps X volts).

 

[fechter]

thunderstruck-ev.com sells a Mars brushless motor (and appropriate controller) which can reach 4000 rpm with 48V. Then of course there's the PMG 132 or Etek, which are brushed. These would involve a much more difficult installation as I'd have to come up with a mounting platform in addition to a transmission of some sort, but it's tempting. Does anyone have any thoughts on these?

Basically, what is considered the best strategy for increasing speed? Let's assume all roads are nearly level to keep the discussion focused.

To achieve a certain speed, you can estimate the power required. It's always nice if the motor has some "headroom" in the power department to improve durability. Improving aerodynamics might be more cost effective than increasing power, but might not be practical. Every little bit helps.

You'd have a hard time packing enough batteries to run an Etek on a bicycle. The motor should be scaled to the vehicle. An Etek-sized motor is good for a small motorcycle.

I suppose your individual needs will determine the optimum configuraton. A drag-racer with limited range and a long range commuter will be quite different.

Early reports on the Mars motor were mixed. It seems like it can't make it's rated power at 48v. I'd like to see some more experience reports on those. The Etek and Perm are proven reliable, but expensive (heck, the Mars is expensive too when you include the controller).

Tim O'brien is working on getting a batch of upgraded controllers for sale. I'll update when they become available. No word on price yet.

For the DIY'er, until we can create a proper how-to thread, Knoxie's repair thread basically covers most of the nitty-gritty details:
http://endless-sphere.com/forums/viewtopic.php?t=158

 

[Lowell]

Now I'm toying with the notion of trying other motors, just on a test bench for a second bike sometime. I can simply throw more power at my current hub motor, which is a valid strategy, but it seems like most or all of the really fast bikes use high-RPM motors.

thunderstruck-ev.com sells a Mars brushless motor (and appropriate controller) which can reach 4000 rpm with 48V. Then of course there's the PMG 132 or Etek, which are brushed. These would involve a much more difficult installation as I'd have to come up with a mounting platform in addition to a transmission of some sort, but it's tempting. Does anyone have any thoughts on these?

Basically, what is considered the best strategy for increasing speed? Let's assume all roads are nearly level to keep the discussion focused.

The 406 at 72v and 35 amps would be reasonably quick, but you never really get to the top of the efficiency curve. Compare that to a 5304 at 72v and you can see the X5 gives a much broader power curve, and better efficiency all around. The down side of course is the extra weight, but if you want to go fast....

 

[fechter]

Another high-power option is an induction motor. Curtis and Sevcon both make induction motor controllers (not cheap). Hiperformance Golf Cars made the AC motors used by Electric Motorsport:
http://hiperformancegolfcars.com/index.php

Almost any induction motor could be rewound and fitted with an encoder that would work with these controllers.

How about an induction hub motor?

 

[CGameProgrammer]

Tim O'brien is working on getting a batch of upgraded controllers for sale. I'll update when they become available. No word on price yet.

Controllers for what? The Crystalyte hubs?

The 406 at 72v and 35 amps would be reasonably quick, but you never really get to the top of the efficiency curve. Compare that to a 5304 at 72v and you can see the X5 gives a much broader power curve, and better efficiency all around. The down side of course is the extra weight, but if you want to go fast....

Actually, I have a 5303, not a 406; I was mistaken.

 

[fechter]

Controllers for what? The Crystalyte hubs?

Yep, the standard 72v/35amp units with upgraded FETs. Depending on which FETs he uses, it will be good for at least 70 amps.

These also work with other brushless motors like the BMC.

 

[Lowell]

Controllers for what? The Crystalyte hubs?

Yep, the standard 72v/35amp units with upgraded FETs. Depending on which FETs he uses, it will be good for at least 70 amps.

These also work with other brushless motors like the BMC.

I can hear the batteries crying already! :lol: