10KW 2WD Build (1 x broken motor = 5KW 1WD now)

10KW 2WD Winter build

Just uploaded pictures from my phone, so not the best quality, but they shall do for now.










Electrical:
20s 15Ah Turnigy 20C Hardcase pack
2 x 18 fet 4110 controllers, stock at 60A for now, but capable of much more
2 x 1000w China hubs (front and rear both with 35mm stators)
- 11awg phase to windings on front hub (done), 10awg phase on rear hub (to be done)
- vented hubs (to be done)

Bike:
120mm Spinner aluminium forks
Ironhorse Boundary Hardtail aluminium MTB (originally with 2 hydro discs, but the front doesn't fit, guess it's calipers for me)
DoctorBass Torque arms for rear hub (on the way)
Ebikes.ca Torque arms and C washers for front hub (need $)


So I'm getting started on this Build, have most of the parts, just need some components for the final assembly, and need to do a little work on the rear hub. I realize I may have to replace the front forks with steels ones at some point, but for now, this is what I've got, and I'd hate to lose 120mm of travel for some shitty steel 80mm cheapo forks. Love to hear what people have to say about it though.

Unfortunately my package containing my 2 x 18 fet's, 2 motors, and spokes for my 26 inch rims was mangled by the customs officials, everything was taken out of the packing and just taped together. When I got it from UPS, over half the 72 spokes were bent (checked and counted, hoping to have enough for one wheel), and had been banging the motors, removing paint on the outside perimeters and chipping some of the covers. No biggie there, I can deal, but the spokes really pissed me off. The controllers were fine other than bent brackets. My front motor wouldn't spin at all, which really cheesed me, upon further inspection, I found a 1/8w resister, yes a resister stuck to the magnets, wedging the stator. WTF is a resister doing in there, they don't even use resistors for building motors lol. Either way I was going to open it, so it turned out alright, although because I tried to force the motor (thinking a bearing was stuck or something), I left a mark on the lams, so possible short and loss of some power, it was hard to tell, it could be fine.

So far, I have run the front hub ~11 guage wire, and sealed the hub with silicone for use in the winter (in the spring/summer I will vent the hubs). I've got the bike down to the frame just begging to have motors put on it. I think I may just buy aftermarket spokes, the stock ones seemed pretty flimsy, although they are being replaced by my supplier. The hubs have the old style hollow axle, welded to the stator.

I've got to get down to the local electronics store and get some lower strand 10 guage, I used super high strand audio power wire for the ~11 guage front hub (stripped wire and heatshrinked it), and it was quite the awful ordeal, I won't be doing that again.

Should have all the parts in the next two weeks, I'm dying to get it together. I'll post some pictures in the next while. Cheers,

Stew

UPDATE

While I was waiting for the spokes, I decided to get started on modifying my motors. I started by running 5 x 18ga insulated copper per phase (tried 7, then 6, all to no avail), think that is about 11ga. Forgot the temp sensor on the rear, but that definitely wasn't happening after I pulled and soldered those phase wires. Then I drilled both the side covers near the bearing, and around the circumference.

I ran my front motor with about 12ga, using thin stranded wire, but I definitely prefer the thicker wire, much easier to deal with. I drilled this as well.

A couple of days ago, before I got the spokes, I was cleaning my place, and unfortunately I moved the flimsy shelf the motor was on(as pictured) without thinking. Ended up having my motor fall 4 feet onto a tile floor, braced with cement. frocking brutal, although I think it may be my instinctual subconcious method of self preservation, telling me not to put a motor at 4 or 5kw on a aluminium front fork lol. My 2WD plan is not dead, just delayed. For a future build with a much stronger suspension fork. I also just got a 500W 320rpm/48v geared motor (without freewheel) in 26 inch rim, nice except a couple of bent spokes, and a rim that I don't think can be trued lol. Got a lot on my plate, but I will get back to it for sure.


Finally received the spokes from the manufacturer to build my wheel, and they sent me the wrong size, 5mm too long, so I wasn't able to use my nice double walled rim, although I tried . Ended up putting it on a crappy (but true) rim from a cheap Canadian Tire bike I had modified as a gas bike (but got tired of it...and the cops). I was very happy with my first wheel building experience, I think I did quite a good job, though possibly too tight. Wasn't as hard as I thought it would be. True test will be when it's spinning with me on it .

- Installed Doc's torque arms, and am just waiting for the epoxy to set
- Set up a 12v Lighting system with rear brake light and dual LED beams (not very bright though, gotta upgrade that)
- Mounted and wired everything


To Do: (for the morning)
- Build battery (already have harnesses)
- Install rear battery box (Marine Dry Box)
- Set up rear disc
- install chain
- reinforce torque arms
- Destructive Testing

I gave it a test with my old pack at 20s (3.84 per cell) while I picked up the back wheel, and that thing bloody flew, the knobby tires moved an obscene amount of air. I bought the packs to upgrade to 24s, but I think it would be silly. Definitely leaving it at 20s at least for the first couple weeks, although those lipos are burning a hole in my shelf just sitting there :?.

Will post pictures soon. Cheers,

Stew

Gonna need some wicked good torque arms for the front forks for starters. Perhaps the best bet would be steel sleeves that clamp to the lowers, which have beefy steel dropouts. It's been done here before, but the thread is years ago.

Then tone down the front wheel amps a bit. I'm considered a pretty crazy mofo, for racing a bike with a 3500w powered front hub. At that point, it was getting a bit touchy to ride. Real easy to spin that tire. In fact, the typical stock hubmotor makes good use of only about 3000w anyway. Any more and it makes the bulk of the increase straight into heat.

But it's still going to wail, with 3000w per hub. Why not just set the amps to 40, and have a bit longer rides before the smoke comes out.

Lol ya, I went a bit overboard with 2 x 18 FETs. They come stock 60A, but I am thinking about shaving off some shunt for the front, especially if your telling me it gets bad at 3500w for you, probably dial it down to 40A or so. I'm used to running 16 inch scooter tires and rear hubs, so don't have any idea of the how front wheels handle high torque. I appreciate the advice. Which motor are you running on the front, what size wheel, and in what voltage/current configuration? I would like to get an idea of the ft/lb's where it slips. Thanks for the advice.

I figure I'll set the rear higher than the front, because I want the ability to wheelie, as well as do a nice rear burnout. I intend to have a 3 position switch to switch between front wheel drive, rear wheel drive, and 2wd. Probably 40 (thanks dogman) on the front, and 60(for now) on the rear.

Is the intended use for Street or Dirt or Race? You'll get beat to death with no suspension.

I run 2hp to each wheel, though to go any distance I have my 3-way programmed as %52(?), 85%, and 120%, and leaving it in the middle.

The FWD slips in rainy conditions, and is not so great in thick dirt or gravel, but it's better than nothing at all. I'm not running at your voltage, and yet I can still beat cars to the other side of an intersection from a dead stop! Great fun 8)

Looking forward to see how this works out for you.
All the best, KF

It's going to be purely for street. I live in Toronto, and have really awful paved roads, but I know them well and have gotten good at avoiding them.

Sounds like FWD slips very easily, more than I would have thought, especially in a bicycle size wheel. O well, I guess I will have to get it together and figure out the best amount of current for it once I get a real feel for it. Definitely starting on 50% lol, gonna be quite the headjerker.

I'm headed out right now to get the copper wire for the rear hub, I'll try and throw up some pics tonight.

I can't wait, only problem is the snow, it would be such a shame to dirty and rust the thing up.... but it is perfect for it. Such a dichotomy, my inner child will probably make the decision though

Cheers,

Stew

Scooter tires will really help gotta have a bigger tread patch. I had threads on my race bike, mostly in the pics section. Look in the two summers ago time frame. Other threads about the race itself from the halloween 2010 race, and the spring 2011 race.

Death race or undead race would be the keywords to search.

I ran a 9 continent 2807 winding on a 26" bike rim. Semi street slick tires, but nothing seriously sticky. Front hub motor only. It was a solid steel fork and I welded tabs to bolt torque arms securely to both sides. That controlled axle spin.

The halloween undead race I ran 24s lipo, on a lyens 12 fet controller. I don't know any real world wattages. My ca was limited to 100v, so I didn't want to risk it at 24s. I was for sure seeing at least spikes at 3000w when running 20s.

There is a lot I don't understand about motor theory, which motor winding saturates at exactly what wattage, etc. But just simple observation of motor temperature shows that power much above 3000w is making a lot more heat. It's fairly clear that in 26" rims, typical bike kit motors start making more heat than it's worth at about 2500w or so. Yes you can add more and see performance increase, but the question is, for how long.

Sounds like you are using completely different motors. I jumped to the conclusion you were using bike motors on 20-26 inch rims. So there could be a big difference in the motors ability to overwatt.

Chances are, no matter what your controllers are set for, you'll see the real world watts back down very quickly once you get moving. Two motors is going to half the heat, more or less, by decreasing the time it takes to wind up to cruise speed. I will guess that you will have no motor heating problems at all, if you are pulling 3000 total watts. It's only about 1500w per motor. Depending on windings and the actual voltage you run, 40 mph on 1500w per motor should be easily possible.

So really, I may have just been flipping out a bit, when I first read 5000w on the front wheel. Mostly, I was just thinking of how hard to controll a drift is when you get one going on a powered front wheel. Rear drifting is easy compared to front drifting.

On my race bike, I had little problems with preventing drifting the front wheel through corners at 72v 40 amps. But when I went to 26s I was breaking traction on the front wheel every other corner. It didn't take long for me to dump it. Front drifting is really tricky.
I was having a lot of problems controlling the bike in the corners. Getting back on throttle was a bitch, I had to ease into it, and in a race it's hard to ease anything. That was theoretically 4000w max, but likely really only about 3500w when moving 25 mnph in a corner and getting back on throttle.

Thinking more about it, you'd be hard pressed to get both wheels to put out 5000w anyway. Chances are, you'll pull less than 3000w per wheel in the real world, accelerating out of a corner you took at 25 mph. So you may never see the front start drifting. But if you do, you'll know what to do. Just dial down the front amps a bit.

Looking at my Parameter Designer config files from last summer, I have the FWD set to 45A Phase/18A rated, and the RWD set to 55A Phase/22A rated. That was enough of an offset to nearly eliminate the FWD from slipping ahead. At the end of my long journey, the wear on the tires was just about even. The hubs & controllers never became too warm to touch, and that was pulling a trailer over huge mountain passes

Born to be Wild... KF

I'm actually running 2.3" nobbies on deep V rims (want to post pictures but can't find my bloody USB A camera cord), so it should help a bit, but I'm totally with you on the scooter tires, besides, the nobbies will be death on pavement, but they came with the bike. I've actually ordered 2 x 17x2.5 motorcycle rims for it, so that I can run huge tubeless tires, but it will be a while before I receive them (for a cbr-125 lol, so not THAT big). Hopefully they will clear my frame, otherwise I have an excuse to switch out this sketchy aluminum for some real steel.

It's interesting that you say the hub just makes a lot of heat after ~3kW. I am used to running my scooter at >3500W, and it stays super cool, only warm on the hottest of days, and that's in brutal traffic, with no hills, and no pwm ever lol, on or off. After I opened my new motors, I realized my scooter stator (from a 16") looks identical to my new china hub stators, same stator width, and it even seems to have the same wind (no specs, I know it's their high speed model and that's it). I must admit I didn't take the tire size into consideration in terms of heat production. The reason that motor stayed so cool is obviously the small tires, high rpm, that makes a lot of sense, wish I thought of that.. A 26" must be brutal on these hubs eh, especially if it has the same wind as my scooter..... Now I wish I got 24's.

I agree, the dual motors should definitely help with the heat output. I originally wanted a 5403, but it just cost too much, so I got 2 of these for less. Hopefully they can handle what I want to do with them, I suspect that once it gets warm it will be super necessary to drill these hubs. The upside is if I burn one, they are cheap.

Nope, your spot on.... dual 26" 1000w hubs. I definitely want way more than 1500w per motor though, at least 4kW on the rear, not sure about the front till I take er for a drive. I would like to get >70km/h (>43.5MPH) at least, hoping for more. In reality though it will really depend on the wind of these motors (78km/h if I am right about the wind), can't be sure until I give them a spin, but I think that's realistic. I'm going to order 3 more packs too, so I'll have 24s to throw at this glorified aluminum foil frame. Talk about QC testing lol.... of my bike and helmet

I know what you mean about the front wheel drift, took me down the other day, luckily not fast (RWD, but hit black ice on a sharp corner). I've made many saves in the past week with the same situation, because there is lots of black ice around now(days are 0c - 2c, nights are <0), but damn is it tricky to get out of. I tend to ride with my feet off the sides when you can't see the lane dividers below the snow, helps a lot. Definitely don't want to deal with that year round though, once I get it assembled I'll have to dial the controllers in. I gotta say though.... it really hurts to buy 2 x 18 FET Genuine 4110(verified) controllers, and then LOWER the amps from stock lol. Isn't that an endless-sphere sin, or something .

Interesting ratio KF, thought it would be more severe, what's your weight distribution like? BTW I love the trailer idea, definitely need to get one of those suckers for the long trips.

Thanks to Dogman and Kingfish, appreciate the incite. I may not be a total newb, but I'm a total 2wd/26" newb lol, so it all helps.

Cheers,
Stew

For the road trip, it was me and the bike and trailer at about 450 pounds according to an Oregon Weigh Station (resolution of 50 pounds, so not terribly accurate). I figured the trailer was pulling 100-135 pounds, counting itself. I weigh about 150 pounds, so that makes the bike < 200 pounds. The batteries were loaded more forward on the frame because the rear-suspension on my particular frame is squirrelly with too much load over it. The breakdown would have been 30 batteries forward and 18 in the panniers: 38 pounds forward, and 23 pounds over the rear tire... not counting ½ gallon of water.

But – unless you are going cross-country, I would suspect your weight will be vastly less. I prefer to have the weight in the triangle which is the designed center of the frame. The previous year I had most of my weight over the rear tire, and in doing so the FWD slipped quite a bit. This last summer, by moving the weight forward, I ensured that the front slippage was minimal. Field testing before I left Redmond indicated that I need only detune the front by a little bit. The shift in mass happens mainly at the start after a cold stop, and not when underway on level ground. As long as forward motion is applied, the lift due to torque of the rear axle is minimal. The trailer was connected at the axle, and it’s CG was lower than the bike, so it’s not going to pull the front off the ground.

If you run saddle bags or have a triangle-bag setup, you should be plenty fine with weight distribution. Guaranteed, you’ll have the whole thing sorted in a day or two of good riding. :wink:

Happy trails, KF

To clarify. You'd be pulling about 3000w or less at 40 mph on the flat. On a hill, you could easily be pulling the full 65amps. Or, increasing speed you'd likely be pullling a lot more too.

I just meant to say, off the line from a dead stop you'll pull max amps. But after a corner at 25 mph, accelerating to 40, you'd pull less amps.

I think I am correct though, that if your tire diameter is close enough to 26" bike, you'll see a lot of heat being made real fast if you start hitting the motors with more than 3000w each. It's just a deal where you can give it more watts, and it will speed up, but it will start making more of the additional watts into heat than you prefer.

Happily, you should be able to cruise at your maximum speed, on a tolerable watt level for each motor. It will just be when blasting up a long steep hill that you will see the full wattage displayed on the wattmeter. I came up with 40 mph, because that's fairly typical for 72v. Somehow I think you might be planning on more though.

With the scooter, the smaller diameter wheel changes things a lot, and it also would have been a different winding from a typical bike hubmotor for 26". Small wheel lugs less starting up, gets to rpm faster.

Were you seeing real world wattage on a display, or just going by the amps x volts theoretical level. Laws of physics say you'd only be drawing x amount of watts for y speed at z wind drag. So you might have been riding cool as a cucumber because your real world watts at say, 30 mph, was only 1000w.

Show us those hubs. I was just backtracking the whole thread to find my mistakes, and noticed 35mm stator.

The "typical bike hubmotor I keep refering to is 28 mm or 25mm or something like that. So it sounds like you do have a bigger motor there, and it should hit the wattage wall a bit higher.

If it's a nice fast winding, you could easily be seeing 45 mph top speed instead of 40, increasing the wattage at cruise. But still, you'd tend to be pulling half the wattage on each motor, and likely would never see cruising wattage over 4000w at 45. So still within the motors running envelope, without going past motor saturation. Likely you still see close to 1500w per motor.

No problem, and the main reason to go dual hub. Works great for KF, lugging a heavy trailer up mountains.

If I ever get healthy again, I want to go on a looooong tour. I have the motors to dual hub my cargo bike, and will do it.

Wow, 450lbs, that's impressive. I would love to go on a cross country trip at some point, I had a trip planned across Canada to BC on my 750 Nighthawk, but insurance wants stupid money after I made steel pudding out of my 450, they want >10K about 6 times my budget. Been craving it ever since.

Totally with you on the weight distribution, I originally had planned on using a bunch of different bags, I bought 2 front saddlebags, a handlebar bag, and a triangle bag. I am hesitant to use them however because 1) think it will look ugly 2) don't want them flopping around 3) a pain to remove from the bike when it's split up into many bags. I also have a front and rear rack for storage (not sure about the front rack with suspension though, because it mounts to the caliper and will move up and down, anybody done this?) I think it would mess up the unsprung weight on my front wheel if I put anything on it.

My current intention is to mount 2 ammo cases to the frame in a removable assembly, pannier style, that should hold everything, and keep the weight balanced nicely. I really wish I could weld though, it would be very helpful for this hobby.

Ya, I totally understand how the motor consumes it's power, but my intention with the high current is to get off the line FAST.

Your definitely right about a lot of heat in a 26" wheel, but with 2 wheels it should help keep the motors in a more efficient portion of their curve, as well as allowing cool down during cruise, especially when I vent them. I'm curious to see their actual heat output, I'm just sort of speculating.

I actually believe it is a very similar winding, if not the same. I'll post pictures soon, just having some technical difficulties. In WYE mode on 20s my scooter goes ~48km/hr, so that suckers would do about 78k in a 26" rim, seems like it would make a lot of sense.

Ya I was referring to my max theoretical amps. I understand it doesn't take full power at full speed, what I was saying is that it was fine in super heavy Toronto traffic, so very much stop and go to full speed. Therefore my average consumption would be very high.

They are standard stators, actual lam width is 28mm I believe. The 35mm measurement is a standard measurement that includes the windings. I'll post pics for ya'll ASAP.

Ya, pulling a trailer makes me feel better, I should be fine, especially with my weight of <140lbs.

Hope you can get on that journey soon dogman, best of wishes.