The far-away pre-build thread

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xenodius

New Member
I know this is a gas loving group here, but I've been reading like crazy about ebikes for a while now and simply must share my reading. I'm incredibly impressed with the performance some of these things put out, and I want something with power, long-term reliability, and easy maintenance. I'm plotting a mid-drive, full suspension downhill ebike capable of 60+mph/12hp/9kw, and 100+ mile range @ 30mph. Thing about ebikes, with the controller I'm considering I can go from zero to full-torque in 2 milliseconds... so the DaVinci drive's torque slip is a crucial function to prevent throttle-twitch crashes. Wheelies are cool, but I'm not crazy... instantaneous 12hp? No thanks =D

**2003/4 Giant DH Comp 21" with good forks,something like this. Though I've recently started leaning toward a 2002 Rotec.
**Astro 3220 in DaVinci drive reduction system for cooling, mounting, torque limitation (no wheelie crashes for me!)
**sinusoidal vector-field controller, if this one hits the market in time.
**~2.2kwh of Headway cells, probably 72v/30ah (24s2p) config.
**Welded-on compartments for batteries/motor mount.

I made a mockup that was inspired by this bike and so used a Crystalyte x5405 hub motor, but that's 24lb's and not as powerful or efficient as the 4lb Astro motor. So I'm ditching that, but haven't made a new model yet. Here's the old one one of several battery configurations, ignore the giant motor by the crankset:
mQWXzl.jpg


Note that in staggered formation, the batteries total 7" wide with the frame between them, with a case they'll be about 8". Since I'm ditching the Crystalyte motor I'm going to reconsider mounting the batteries radially around the down tube; that'll take advantage of the inner triangle space I selected the DH comp for, and keep them out of my pedal range. I'll decide when I have everything; I may like having something to hold onto with my legs while I'm going 45mph =) Or zipping through trails...

Depending on speed, incline, wind, etc. the efficiency will range from about 20 to 60 watt-hours per mile (Wh/mi) so the electrical cost is .72 to .24 cents per mile, while the cost of battery wear comes out to .48 to 1.44 cents per mile. That means it costs, at most, 2 cents per mile to operate... but on the low side (30mph), it gets the equivalent of approximately 600 miles per gallon. The downside is that most of that cost is up front in a $1,500 LiFePO4 battery pack. I could go with a MUCH smaller, cheaper, but shorter-lived (cyclically and range) LiPo pack, but I'm not. Another upside is that free EV charging spots are being put in all over the west coast, including on the interstate...

I'm going to mount the BMS and charger inside an Otterbox DryBox and mount that on the top tube behind my bars; it's out of the way, gives me a place to put important items (e.g. keys, wallet) and makes it easy to take the charger with me everywhere. I'll just leave everything hooked up, leave a cord in there, and then I can just pop it open and plug it in anywhere. I'm strongly considering getting a ~3kw charger despite the cost, just so I can take this thing on the interstate and charge it in 30-45 minutes before going another 100 miles or so. I'm also planning on putting a Freeload rack on it. =)

Anyway, thought I'd post here and hear thoughts =) You guys raised me into this hobby, after all =D
 
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that looks like it is gonna be one heck of a build. i love my electric bike. please keep us up with your progress, yes most are gas bicycles on the forum but i dont think most of them have experienced ebikes. i know as soon as i did my gas days were over
 
Ideally, it'll be my be-all-end-all vehicle. Unless there's a LOT of snow outside, I guess... I want to be able to throw slicks on it and commute, then throw some knobby's on it and tear things up on the weekend =) I just hope I can save up enough for all the parts!

I heard zipties are good "bike chains" in the winter =)
 
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In the spirit of remaining maintenance free, and the realization that the cost and maintenance of a full-suspension frame is more or less unnecessary for riding on the roads and is really just a matter of comfort, and impatience waiting for the necessary things to happen to make this build feasible, I think I'm going to sell my cruiser and switch gears.

I'm going to buy a cafe bike from Bikesdirect (this guy: http://www.bikesdirect.com/products/motobecane/elite_adventure_x5.htm) and go with a hub motor and triangle pack. The advantages of a mid-drive are significant, but in reality the minor gain in efficiency isn't really worth the extra wearing parts to me, for my commuting needs anyway... I can live without my weekend warrior machine for a little while. =) Besides, if I go with a hub motor then I'll be persuaded to pedal along =) The HS3540 Crystalyte hub can handle about 3kw without modification, and a few people have pushed it up to 5kw or so by filling it with ATF to increase heat conduction and water resistance. It's also one of the few hub motors that can fit a 7/8 speed cassette and disc brakes without begging for more room.

So I'm going to go with just a 72v/15ah 3C Headway pack, fitted inside a 1/8" ABS triangle box (score/break, ABS glue to set, acetone to "weld" ala Patrickcz) which should have enough room to fit my controller, a Mogotracker, BMS, and charger as well. The large triangle of that 21" hardtail could fit more than twice that many batteries laterally, so I hope to squeeze those extras in with it and keep the pack under 3 or 4" wide.

I will pay less, get enough power (not as much, but enough) and it will remain much more bike-like than motorcycle-like. Additionally, I'll never have to worry about chain breakage, and I can use regen braking to save brake wear. In fact, I could ride this bike and only put wear on the battery and both wheel bearing sets.

Another issue with a full-suspension mid drive would be squat during acceleration. Not a real issue, but this solves that too.

I see this becoming the bike I ride, but my wife falls in love with so I give it to her and then get permission to build an even better one that I'll ride. =D

PS: New sinusoidal VFO controllers will drastically increase the efficiency and performance of these hub motors when they hit the market, but will not significantly affect the performance of high-efficiency RC motors that lose efficiency through a drive system, so this build will have more upgrade potential as well...

PSS: I plan on replacing the fork on the cafe bike with my Monarchs from Norm =D

PSSS: If I later decide I must have a full-suspension frame, I can simply take the parts off the cafe bike (all plastic or in the wheel, so no scratches or anything permanent!) build a new battery box, and put them on a FS bike! But in reality I probably wouldn't put a high-speed hub motor on a mountain bike. I might, but... probably not.
 
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from what i have been seeing and experience with full suspension frames is that they cost a fortune for a good one. the cheap full suspension bikes you see are junk. to get a full suspension bike that is worth a hoot will cost upwards of $3,000.00 plus. i think you are making a good decision and will be very happy with it. i am ordering a trek pure today which is basically same as an Electra townee. like a motorcycle you can just put your feet down when you stop and the pedals are forward of the seat so you can sit straight up and down and take the pressure off your hands and back. the design is basically in between a cruiser and a recumbent bike. i will be putting the magic pie on it with a 48v battery. its a light aluminum cruiser to and weighs only 28 lbs. i think it will be the perfect bike for an electric motor
 
Yeah, the full-suspension frame I wanted was a Giant DH Comp, which would take gobtons of abuse... but for a used bike, I'd be paying $700 - $1000. Granted, those are coming with Marzzochi Monster Triple Crown forks, which by themselves are worth over a thousand.

Adding all the components I want to the triangle would also significantly increase the unpsrung weight of the bike (since my weight is, to a degree, sprung by my own biomechanics) which would put even more stress on the linkages. Building the bike this way will minimize maintenance and cost, while retaining necessary function. =) Plus I'll have a larger triangle for more goodies and leg room. =)

The bikesdirect cafe racer also has a great derailleur for high speeds and decent hydraulic disc brakes, so it's ready for high-speed. =)

EDIT: even though it's a "cafe" bike, it fits wide 2" tires and would definitely be capable of low-speed XC trail riding. Though I don't think I'd do that to it. Also, I'm very impressed with some of the ABS battery boxes I've seen. No need to worry about insulating, and it "welds" incredibly easily with acetone or ABS cement. Just paint it to protect it from UV damage, and you're set!
 
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I don't think I would be taking a 50 pound ebike over 25 mph without full suspension. at least not with the roads they are around here. I have a 60+ lb ebike that goes 40 mph and even while standing up and absorbing bumps, that bike takes a beating. To me it's just not enjoyable always scanning the road surface for potholes and the like, I'd rather spend a little more, get a LOT more bike and feel safe.

I know why you want the Giant DH Comp, here's one:

20120709_082221.jpg


Look at all that room in the triangle! Since you ride in WA state, disc brakes could save your life! Reason alone to go a few extra $$ and get a real bike. Now for just cruising around town, a nice beach cruiser would be a good choice. But if you plan to use it like a vehicle, make sure to be safe, suspension and decent brakes fall into this category.
 
Oh, I'm definitely going to have disks-- in fact, the cafe I posted has hydraulic disks, though I might replace one with my BB7. For now, I think I'm still going to go with the hardtail-- roads aren't bad here and there's only two over 35mph. I think a cushy full-sus bike would make it harder to pedal assist with the motor-- if I go full-sus, I'm also going to be temped to take it on hilly trails, and for that a mid-mount is the better approach. For now, I'll stick to 12 gauge spokes. And if I find it uncomfortable, I might go with a suspension seatpost. There really aren't any significant potholes around here; I was quite comfortable riding my hardtail gasbike around at 35+mph. With an ebike I could stay to the less-worn bike lanes, too.

If I do a Giant DH build, I could just barely fit 40 Headway cells in the triangle, staggered and pointing laterally (I built a Solidworks model out of the 19" frame, but I'll get a 21", so should have even more room.) Use the smaller 4.5" 10ah cells in the crank and leg area, and the larger 6" 15ah cells in the rest of the triangle, and you could have a pretty compact 60v25ah LiFePO4 pack. But I still won't put a hub motor on a full-sus, just to inefficient for everything I'd want to do. Also, there's plenty of room ABOVE the top tube, and I don't think it'd be crazy to put a few bats along the top if you had to.

I considered going with a "soft-tail" like the GT-LTS, but... I dunno. If it's an issue, I'll buy a GT-LTS frame and move everything over. But for now it probably won't be worth it to me. Bikesdirect.com is super cheap because the bikes aren't yet assembled, so it's hard not to go for something new. And there aren't really any new, out-of-triangle suspension bikes.
 
Huh, I bet a happy time engine would fit in one of those Giant DH Comps, that looks like an awesome bike!

You should take a look at 1/5 scale RC motors, they're incredibly powerful for how light they are, and the controllers are tiny and light. As long as you gear them appropriately so as not to fry them stalling out, I would think they would be very reliable.

I have a crude SLA powered brushed DC electric bike and it's a riot to ride, I bet a light bicycle with 5+ hp electric would feel like flying!

More power to you, the cost of cells is what's holding me back from going crazy with LiFePO4 packs on mine and getting a 9 hp in-runner motor. Electric bikes feel so special to ride since you are able to take in the surroundings more, and people smile when they see you instead of looking all pissed at a 2-stroke.
 
Thought I'd stop by and say hello to all you good folks here, it's been a while and I've traveled the internet and come back with the longest-lasting of any revisions to my plan for a car-free life. =) I'll provide links to any components or inspirations if anyone is interested.

I should add that John in CR has a 6-phase BLDC motor, the "Hubmonster", he just started selling it. The the big brother to the big brother of the Minimonster. It's rated at 15kw, but he's pushed over 30kw through it for a couple minutes at a time and claims it never got above 95°C. (460 amps) Damn 94% efficiency! Not sure if that kind of motor appeals to anyone here but it's awfully impressive.

CELLS: 28s Sinopoly 60ah LiFePO4 cells ($75/ea, ~$280 shipping. 4.0lb ea.)
CONTROLLER/ELECTRONICS SET: Sinusoidal controller running on halls. 14kw, 0-98v (IRFB4468) continuous regen braking (not on/off, just twist throttle in reverse), temp monitoring, power profiles, kick-down throttle (e.g., regardless of power profile, a little extra twist results in maximum preset power) integrated BMS for 24-144 cells based with up to 6x $15 expansion boards. Also has programmable DC output, which can be controlled by a 9-button panel on throttle (lights/turn signals). Fully programmable on-the-fly. More efficient than 6-step trapezoidal controllers, smoother starting, more torque, and totally silent. Capable of reverse. Preorder only right now...
MOTOR: "Minimonster": 6kw rated, 2-speed (series/parallel) hub motor, 20lb, 6" stator, 7" diameter total, 190mm dropouts, built-in drum brake, 17 or 8 kv. 93% peak efficiency with a trapezoidal!!
FRAME: DIY Self-centering leaning delta recumbent trike-- FWS, FWD, MBB, OSS, SWB. That's front-wheel steer, front-wheel drive, moving bottom bracket, over-seat steer, short wheel base. Acronyms. Going to use Prince/Calleja type swingarms, like the Munzo TT but more stable.

WHY: Recumbents have a lower profile and are therefore much more aero and efficient. They are also more comfy IMO; the frame is designed to let me sit in a physiologically neutral position, e.g. a zero-G position, based on anthropometric measurements. There will be room for batteries under the seat. As a delta, there will also be room between the rear swingarms for a small storage trunk. As a leaning trike, I will be able to corner better than a linear track vehicle especially on slick surfaces, e.g. ice and snow. Plus, it has a much much lower CoG. There's a reason leaning trikes are popular for ice racing. =)

Also, recumbents are better suited to fairings and so I will be able to build a fairing to protect myself from the elements and increase efficiency even more. There's no reason this fairing shouldn't include solar panels, and the tailbox/trunk could include a fold-out solar panel stand. Based on my estimations this is surprisingly practical, and i should be able to design a stand of small solar cells that can be folded out when parked to charge the vehicle from zero to full within 8 hours on a mostly sunny day. For a 5kwhr vehicle, this is impressive. I should be able to get 90 to 270 miles on a full discharge. I could go 45mph up a 10% grade for 45 miles @ 85% DOD. I could expect 90 mile range at 55-60mph speeds; I will almost never take this vehicle that fast. The ability to charge a vehicle independently and anywhere is truly invaluable, but is only a long-term goal.

I am toying with the idea of having a 'regen' pedal generator instead of direct-drive pedals. Among many things, I could pedal when stationary to keep charging or to power other devices from an inverter. It would also eliminate virtually all wear points from the design. Fully electric drivetrain and transmission. The only moving parts would be wheels and suspension.
 
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You've got the right idea.
The John in CR motors are supposed to be awesome and i'm looking to get one soon.
How you are going to fit those batteries on that bike is beyond me, hehe...

Regen cranks sounds cool. Maybe add a PAS sensor to control the motor as well? then you can forget the chains and such!

A little 250W currie motor or a 36v 200W euro-spec hub motor might be suitable for that kinda thing.
 
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