What's the new way to get 50mph from a hub motor build?

[auraslip]

Been gone awhile. Been checking up tonight. Lots of cool stuff going on.

Has anyone come up with a way to run at 50mph under 100v with a hub motor that won't overheat?

Cromotor looks nice, but i'd rather stick with a 9x7 that overheats by the time my commute is over than go 100v+

John in CR's motor looks nice. If it was a bicycle hub motor.

My HS3540 killed my 18fet and 12fet while providing only a bit more power while taking only a slight bit longer to over heat. Something may be wrong with it. In any case, I don't trust it.

Oil cooling would be wicked, but no one has found a way to keep it from dripping on the carpet. Can't have that if I sleep at my girlfriends.

Seriously considering dual 9x7s or just buying and modding two and throwing in the back up motor when I cook the first one.

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btw, I need 50mph because part of my commute is 5 miles of busy one lane country road with no shoulder. Speed limit is 35, but people still like to go 50mph down it.

 

[wesnewell]

If you want 50mph for 5 miles without over heating, then get a recumbent bike or trike to reduce drag. Might even get it with a good superman tuck and a 1000w 470rpm@48V motor at 100V. Sim shows 58mph with full recumbent, hs3540, 40A controller, and 96V for 22 minutes before over heating. That's about 20 miles.

 

[dogman dan]

Dual motors so you run half the watts through each might be your best approach, if you want to do it with cheap 9c type motors. Unless I have it all backwards yet again, it's the high amps that fry the motors, not so much the 100v. So two 100v 25 amp controllers? Cruise at about 3000w or so, but only 1500 going to each motor?

I see no reason not to do this, other than the usual deal about easy on the throttle while cornering. Drifting the front wheel gets to be a problem when you really power up a front hub.

 

[Spicerack]

John in CR's motor as a mid drive, but going direct to the rear wheel (it has two speed anyway so let's keep is as KISS as possible). You still get to pedal if you want (why?), get regen braking and also avoid the dodgy one way bearings etc at the pedal crank. Bit more stuffing around going mid drive but you'd get your 50mph that way. If I do another build it will be this motor going direct drive, probably 62-72V (15-18S), but probably in a custom/very modified DS frame.

Another possible option is the new GNG kit but that's still in ES testing phase! Yeah, I know, not a hubbie but unless you go CRO or similar and spend lots of money, you're going to struggle to get 50mph reliably.

 

[miuan]

40mph is as much as I ever wanted to go with a single 9c type motor. 50mph is a task reserved for two of them, unless you want to do extreme mods to your ride. been there, liked it. never liked to travel that fast for long though.

 

[dogman dan]

It might be the best thing, for you to go to non hub. A motor with a blower in it would help, but you gotta listen to chains and gears.

 

[MadRhino]

NP doing 50 Mph with a cro-motor in a 24in wheel running with 24s Lipo. Even does it on 10% uphill, if you build light weight and feed enough power. 8)

 

[dogman dan]

Like me, he's waiting and hoping they'd send him a free cromotor for the review. :lol: Double motors likely the easiest most affordable route avaliable to him.

Didn't you sell me your old frontie? Or was it somebody else?

 

[auraslip]

Yeah, I sold you my first hub motor. Hope it's still working for you! I never took that above stock.

I really don't want to go with two hubs. Even at only 3kw the front wheel will spin. Then I'd have to do heavy mods to the expensive fork I want to use. And then I'd have to have double the wiring. bla bla bla. I was using it as more of a rhetorical argument to point out a gap in the ebike hub motor market.

Sucks that mid-drive is the way to go! Where do you put the batteries. Already I'm having trouble finding a hardtail frame that's tough enough to handle the speeds I want, and fit the batteries safely. Let alone a motor!

Thinking this would do the trick. Or this.

All dat metal and square chain stays!

Even If I found a FS bike that would fit the batteries, I'm too mechanically retarded to deal with revamping the suspension to deal with all the torque I want + 40 lbs of batteries and chargers. So you imagine the problem I'd have with a mid drive!

NP doing 50 Mph with a cro-motor in a 24in wheel running with 24s Lipo. Even does it on 10% uphill, if you build light weight and feed enough power. 8)

I was doing the ebike.ca simulator using the "noname5004" motor and completely missed that It would do 50mph with 24s. I don't know how!!! Oh yeah, I was doing 22s - not 24s.

Looks like it will work out. I just don't like doing 24s. 22s is much safer. OTOH, with a 20ah battery pack, I'll still get the range I want only charging to 4v per cell. Still, I'm not sure how reliable it will be running 4v shy of the fet's ratings every day. Wish the cromotor was just a touch faster....
And I won't get to run 17" motorcycle rims either.....

 

[d8veh]

I found a very cheap way to get a hub-motored bike to do 50mph.
I bought a Q128 motor from BMSBattery and found that it was totally gutless with 20 amps, so I upped the current to 25 amps, but it was still gutless. No torque at all. I was so discusted that I took the bike to Beechy Head near Dover and chucked it over the cliff. It just reached 90mph before it crashed into the sea.

 

[dogman dan]

Wouldn't running 1500w-2000w into each of the front and rear motors get you the speed you want? Assuming you volted up to 100v or so. 3000w on a front hub is touchy, but not that bad if you can ride. Above 3000w was where it got really tricky.

Yeah, you'd have to do up some torque arms better than normal up front. something like a sleeve that clamps the fork rather than a hose clamp to hold em in place. Big deal if the front wheel spins when you goose it. You learn to like it. Just don't romp the throttle on the corners so hard. Use speed two on a switch when in town, and save 3 for the straight shot you need 50 mph for.

Anyway, if you wanted to try two motors on a budget, I could sell you back that motor.

 

[John in CR]

Dual 2805 9C's or Dual Xlyte 3548's or one of either with really good aero, but the best way is to build one of these which holds 65mph with voltage sagging to 75V as long as your battery can last and hold 60 with you aboard up whatever hill a car can, and get nowhere close to hot. HubmonsterHE loves going fast, and it's performance is based on fact, not speculation like elsewhere in the thread. 60-65 is a bit too windy, so it's nice to be able to let off the throttle quite a bit to slow down to 50mph, which is a pleasant cruising speed on the hwy. Get plenty of battery, because speed takes power and chews through electrons quickly. 8)

John

 

[amberwolf]

Been gone awhile. Been checking up tonight. Lots of cool stuff going on.

Has anyone come up with a way to run at 50mph under 100v with a hub motor that won't overheat?

I dunno if there are any hub solutions in them, but you might want to check out the spate of recent (last few weeks/months) "i'm a noob and i wanna go 50mph" threads. There's also at least one or two experienced builders with new threads about doing that (agniusm for sure, I forget the other).

I do wonder about a hardtail at 50 on those FTM roads, if they are still in as bad a shape as they were when I lived in the area in the early 80s. :lol: I'd want FS DH stuff for 20-30MPH on them the way they were then! (some of the gravel roads were kept in better shape)

 

[Paul_G]

Been gone awhile. Been checking up tonight. Lots of cool stuff going on.

Has anyone come up with a way to run at 50mph under 100v with a hub motor that won't overheat?

Cromotor looks nice, but i'd rather stick with a 9x7 that overheats by the time my commute is over than go 100v+

John in CR's motor looks nice. If it was a bicycle hub motor.

My HS3540 killed my 18fet and 12fet while providing only a bit more power while taking only a slight bit longer to over heat. Something may be wrong with it. In any case, I don't trust it.

Oil cooling would be wicked, but no one has found a way to keep it from dripping on the carpet. Can't have that if I sleep at my girlfriends.

Seriously considering dual 9x7s or just buying and modding two and throwing in the back up motor when I cook the first one.

----------
btw, I need 50mph because part of my commute is 5 miles of busy one lane country road with no shoulder. Speed limit is 35, but people still like to go 50mph down it.

50 MPH on a bicycle is nuts every day for 5 miles.

There is only one bike I would trust with my life and that's a Stealth Bomber.

 

[auraslip]

It's all about knowing where the bad sections of road are and planning accordingly. The roads aren't too bad, but there are a few big bumps that need to be taken standing up if you hit them at full speed. The roads are actually pretty good around here. Especially the stuff that I have to keep up with traffic on. It's definetly a trade off between comfort/safety and utility. I'd rather be able to go 50mph there and back with out worrying, but have to slow down if I'm on a road I'm not sure of. The other option is spend a grand for a decent FS and have the range of a remote controlled car. I've tried commuting on 22s10ah. IT'S NOT FUN EVEN IF YOU CARRY YOUR CHARGER!!!

I guess the other option is to wait for farfle/phasors/hal to start producing FS frames. Might be worth it considering this will probably be the last ebike before I move up to motorcycles. Anyways, it'll be months in the making. I'm just tossing out ideas at this point.

 

[Spicerack]

Yeah the bomber is nice if you have the cash, but for most of us mortgage bound married with kids types, a second hand downhiller is just as good. My Norco Shore was just under $500 and is rock solid at 60+ km/h. Haven't done 50mph on it but I'd trust it. Certainly I would never suggest anyone tries it on a rigid/front suspension cheapie-that would be nuts. 8)

 

[auraslip]

Dogman, I may take you up on that. I'm just worried that having 15lbs mounted on the front fork will interfere with it's proper functioning. I have some pretty thought out ideas on how to do it too. Pretty much just like your idea..

"i'm a noob and i wanna go 50mph" threads.

Ah, the classic, "I have no idea how much money I'm about to spend threads." Love those

John, by the time I spent the money on the tools, and took the time to learn how to make a reliable high powered mid-drive, I could of built a picture perfect ebike that'd run perfect for a decade. I love your bike. Mad max for the year 2012! Don't take it the wrong way, but I think the saying goes, "Your non-hub bike sure beats the pants off of mine, when it's not broken." :wink: Seriously though, I have crazy respect for people with the mechanical skills to pull something like that off.

 

[MadRhino]

Looks like it will work out. I just don't like doing 24s. 22s is much safer. OTOH, with a 20ah battery pack, I'll still get the range I want only charging to 4v per cell. Still, I'm not sure how reliable it will be running 4v shy of the fet's ratings every day. Wish the cromotor was just a touch faster....
And I won't get to run 17" motorcycle rims either.....

I charge 100.6v for 3 years now. The 4110 fets are taking it NP. I still fry a controller once in a while, but they are set pulling 150A batt current so it is not unexpected, and considered performance expense in my case. for me, the cro motor is a tad too fast for most of the riding conditions that we have here in the mountains. I ride the 5404 when trails are bad, but I love the speed of the cro motor when it's nice. On the street here in town, it is fast enough for there are very few places I can ride full speed.