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Discussion Starter · #1 · (Edited)
Because my electric Triumph GT6 is 1200 miles away from me for all but 2-3 weeks out of the year, I needed some sort of EV project to keep me occupied.

Being that I currently use a bicycle for all of my < 30 mile transportation needs at the moment, I decided to build something that would enhance the utility of a bicycle greatly to something comparable to that of a car, without sacrificing its inherent advantages over a car in terms of operating cost.

The entire theme of this vehicle's design is "F*** the Texas DPS", so it must do exactly that.

Two months ago, I purchased a Thunderbolt recumbent tadpole trike that needed a bit of work, as a donor. It will be getting a set of rear torque arms and thicker dropouts for the rear, a motorcycle wheel and tire in the rear, and some thick, sturdy DH bike rims and tires up front, probably with Maxxis Hookworm or Roundworm tires with thicker spokes.

You can see an old image of it below, before I restored it:



It is almost rideable as is, but I do not have a body built for it or an electric drive selected yet. The choice of a single ev drivetrain component will influence the selection of all of the other parts, due to my design constraints. When 100 lbs is the weight limit, every ounce counts for something. An extra ounce of battery is close to a mile of added range at 30 mph.

I want it to have ass-hauling capabilities(50+ mph top speed, 0-40 mph in under 4 seconds), long distance travel capabilities(Corpus Christi to Austin in under 8 hours at 25-30 mph on one charge), the ability to smoke its tires, and the ability to function as a pedal velomobile when the battery pack is completely dead.

There are trikes that have been built to this acceleration and top speed spec while weighing under 100 lbs:

https://www.youtube.com/watch?v=WKAMus3oSdw
https://www.electricbike.com/50mph-monster-electric-trike/

https://www.youtube.com/watch?v=MKDFXDGNVsQ

Both would be improved significantly with the addition of an aerodynamic body shell.

Getting pulled over in this vehicle will be an inevitability, so it must be 100% legal to operate without tags, title, insurance, registration, or a drivers' license on Texas roads.

The way that Texas e-bike laws are written, as long as the trike weighs under 100 lbs, and cannot exceed 20 mph on electric power unless it is being pedaled, it is legal as an electric bicycle. There is no power limit, and a maximum speed does not exist as long as it is being pedaled. You can read the law for yourself in the link below:

http://bicycleaustin.info/laws/tx-bike.html

I'm intending to build a body shell with a Cd of under 0.2, frontal area of under 0.55 m^2, and am guessing the tires will have a Crr of 0.008. This body is key to getting the efficiency that I want. The unladen vehicle mass including ev components and batteries will be 44-45 kg. I would be most of the weight, at somewhere around 65-70 kg.

I want to be able to pedal with 100W, have the electric motor kick in another 150-200W or so, and keep doing a steady 30 mph on flat ground, for roughly 7-8 hours on end. If the battery runs dead, that same 100W would keep me at a steady 15-16 mph on flat ground, which isn't much more power than is required to walk, or if I exert myself a little, maybe 20 mph for 150W, 30 mph for 250-300W, or 50 mph for 1 kW, using no electric assist at all.

I will set up whatever ped-elec system I purchase to allow full power to the motor if I'm pedaling particularly hard, with 1 kW of force or so provided by my own legs, which I'd only be able to maintain for a few seconds without getting tired, in which the electric motor would then kick in 15-30 kW, also of which would only be maintained for a few seconds before the motor overheated, and allow this vehicle to blow the doors off of most new cars from a stop for a short drag race. The vehicle would be expected to reach 50 mph or so before the power scaled back to 1 kW peak from the motor or so, in which case a car would eventually overtake it. Lacking a front suspension, 50 mph may even be overkill for this vehicle.

I want to use it to do donuts in parking lots and intersections, taking long trips, and racing cars for short < 1/8th mile drag races. All of the things I normally use a car for when I need to!

There are lots of low-weight RC airplane motors that can make massive amounts of power, such as the Astroflight 3220 that can make 30 horsepower peak at 44.4V, while weighing only 5 lbs. The only problem is that lack of a torque sensor makes them unusable for ped-elec systems, but they maybe could be modified for that purpose.

High thermal efficiency with only 100-300W desired is much more important a parameter than maximum power capability, that being said, but I need a motor/controller solution with good peak power too. I can't budget more than 15 lbs or so for the motor+controller+charger.

I also need a reliable LiFePO4 battery with at least 120 Wh/kg specific capacity and anywhere from 10AH to 25AH in size depending on what motor and controller are chosen. I need 20-25 lbs of battery or less in this thing. I've heard of 25AH CALB CAM cells on this forum and elsewhere, but have not been able to find any data on them during my online searches. The CA40FI, CAM72FI and CAM80FI are readily available for purchase with plenty of info, but all of them are far too big for my needs. I have come across a CALB CAS 20AH cell on these forums that might make for a good choice; 25 of them could allow a 80V 20AH pack yielding 1.6 kWh, weighing in at 24 lbs, with the reliability that CALB cells are known for and 10C peak discharge! This would be a 16 kW pack!

http://en.calb.cn/product/show/?id-631

As for body material, I am thinking of using paper mache to build the body shape, then fiber-glassing over it, but am also considering dacron on wood frame construction, and zote-foam. I have to keep the body shell light too, preferably somewhere under 20 lbs. More important than weight though, is making sure it is both low drag and sturdy, but 20 lbs is about the upper limit of what I can do, and I don't have the tools, skills, or money to justify using carbon fiber reinforced plastic(which would be the ideal).

An Anarchy sign front emblem is a must, of course, as this will be a vehicle built to cater to anarchists. Hippie chicks in Austin are totally going to dig this thing! :D




This will serve as an initial prototype. If I make a second one, it will be a composite monocoque with both front and rear suspension built from the ground up to handle 100+ mph and add an additional 5 lbs of battery or so, and maybe go with 4 wheels instead of 3.
 

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Awesome idea for an ev and the quest for adventure--and you'll be getting plenty from the hippie chicks too.

Not sure what you meant by a torque sensor, maybe a tachometer for measuring motor speed?

If weight is your primary constraint then maybe a 'hotter' chemistry cell would provide more energy per lb, but that might hit your wallet harder too.

Press on regardless, and keep us posto de progresso.
 

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Sounds fun... from your specs I figured you must've read up on the Matt Shumaker monster, and sure enough you even linked to his video.

I think that particular bike has dual astroflight 3220s running in the heavy duty Davinci drive system IIRC (though it's never been clear how you hook two motors up to one if those?).

Good luck with this beast. Subscribed.
 

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Discussion Starter · #5 ·
It is too easy to smoke a skinny little rear tire like that!

This is one I built a few years ago.
Any links to some info?

I want as low rolling resistance of a tire as possible that can handle highway speeds and not require too heavy of a rear wheel/tire. It has to be able to be pedaled when the batteries are drained, so a rolling resistance coefficient of less than 0.01 is a must..

Considering the use a Pirelli ML75 in the rear with two Maxxis Roundworms up front.

The tire on yours is way too damned thick! I need to be able to pedal this like a velomobile if the battery is drained, effectively making my range limitless, but with 200+ miles of electric assist and very light pedaling at 30 mph.
 

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Hmmm, I have been toying with the idea of a shelled trike myself. A Cd = 0.2 is a bit ambitious, but doable. Let me know a bit about the shape you have in mind, because I might be able to help. I can run a few CFD simulations to explore the aerodynamics of this thing.
 

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Discussion Starter · #7 ·
Thanks. I need to get to work on finishing some of my drawings. I have an idea of what I want now, but no wind tunnel to do any tests.

I haven't worked on it much lately, but will be getting back to it when I return to Texas from my vacation.

An Anarchy symbol as a hood ornament will be obligatory, even if it might suck up 1-2W at 30 mph.
 

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Discussion Starter · #8 ·
I've been spending more time riding it and enjoying it than working on it. I have put more than 100 miles on it in the last 2 weeks.



Currently, it has two Weinmann 20" double-walled rims and Maxxis Hookworm tires up front. In the rear it has a Schwalbe Marathon. Avid BB5 cable-actuated disc brakes.

Anyhow, a few issues have manifested that have made me re-evaluate my attainable specs with this chassis:

-Trike weighs 71 lbs unladen. No body. No motor.
-It corners very stable at 25 mph. At over 25 mph, even on a smooth road the suspension feels wobbly.
-Pedaling it is already much more difficult than a standard road bike. I expect this to change once I get a decent body on it. I can top out at 26 mph on flat ground on a day with calm wind, versus 31 on my beater road bike.
-The trike requires frequent mechanical adjustment. I have adjusted the brakes at least 3 times in the last 300 miles. I've repaired the seat once in the last 300 miles. I have tightened the wheel-bearings twice in the last 300 miles.
-the best ground clearance I will be able to get is 2.25" without moving to larger wheels.

I will need a stiffer shock in the rear.

I will be getting a 4x8' sheet of 1/4" plywood to make my floorpan out of and will build a body around it, both of which will be attached to the trike frame and designed to be easily removed with a socket set. I expect the floorpan plus body to come in at around 12 lbs.

I am eyeing purchasing second hand a Lightning Rods smallblock kit if the seller still has it. This is only 1.5 kW, but it is more than plenty for this. It's 11 lbs.

Add in 2 lbs for cables, lights/signals, wires, and such, and I'm left with only 4 lbs for battery.

I could use some A123s and get a decent 25-30 mile range @ 30 mph, and carry multiple charged packs as luggage and swap them in as needed on long trips. I could also remove 10 lbs or so from the frame through drilling and removal of extraneous material, which would greatly increase battery storage.

I have gearing to exceed 40 mph. 1.5 kW of motor will certainly do it with a body. Even half that would be enough. 1.5 kW with the rider inputting a constant 750W for the duration with the total laden vehicle weight at 300 lbs(me, the 100 lb trike, camping gear and any spare batteries) could allow 0-40 mph in ~7 seconds starting in top gear. That is a car-like level of acceleration and would be okay. I am not confident that the rear tire would get the traction for that, mind you, as I can already break traction just pedaling it...
 

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Hi Toecutter

More difficult to pedal than a normal bike?
That surprises me - I used to have a two wheeled recumbent and it was much easier and a lot faster than a normal bike and that was without a fairing

On the flat I could keep up with much much fitter cyclists - the buggers left me on the hills
If I was cycling with people of about my fitness level I used to have to stop and wait for them
 

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Discussion Starter · #10 ·
Hi Toecutter

More difficult to pedal than a normal bike?
That surprises me - I used to have a two wheeled recumbent and it was much easier and a lot faster than a normal bike and that was without a fairing

On the flat I could keep up with much much fitter cyclists - the buggers left me on the hills
If I was cycling with people of about my fitness level I used to have to stop and wait for them
The frontal area from my 3 wheeler is significantly higher than any 2 wheeled recumbent I´ve seen. It is 36 inches wide.


20 mph in this requires the same effort to do 25 mph on my road bike.


It being 71 lbs of bike(soon to be 100) doesn't help either.
 

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Hi Toecutter

I'm still surprised - I rode a few recumbent trikes they were all pretty quick - the extra width didn't mean much extra area and the recumbent position more than compensated for it

Maybe it's the wheels - the ones I rode were all skinny bike wheels
 

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Your front wheels probably have too much toe-in or toe-out. That creates a lot of
drag you don't have to worry about with a 2-wheeler.
 

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Discussion Starter · #13 ·
Your front wheels probably have too much toe-in or toe-out. That creates a lot of
drag you don't have to worry about with a 2-wheeler.
When I had originally set my toe-in I chose to have the front wheels have their front width narrowed by 1/16th of an inch relative to their rear.


After 350 miles of use, it was at a difference of 3/4 of an inch. I reset it again and gained another mile per hour of cruising speed and 2 mph of top speed. I suspect that my wheel hubs and axles are too weak for the pot holes.


It still isn´t as fast as my road bike.
 

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I would have set the toe at zero

But if the front is so flexible that the wheels are steering themselves
After 350 miles of use, it was at a difference of 3/4 of an inch.
Then you are buggered

The extra drag from your front wheels doing what they want to is want is killing you

If you can make it all stiff - even if you add weight - it should be FASTER than your road bike

Just a thought - road bike? - are you getting into a full aero crouch?

If you are then your road bike may be as fast as a recumbent trike

I could never go any distance like that - far too uncomfortable!
 

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Discussion Starter · #15 · (Edited)
August of 2016, that frame sheared apart in the front from excessive pedal force. I replaced it with a KMX and ordered an aftermarket front suspension. Below is what I built off of it, but it remains unmotorized due to lack of funds(long story: had to save my mother's house from foreclosure with my savings and am currently jobless). It has almost 20,000 miles on it now!








Videos of me pedaling it down the street at 30-40 mph:

https://vimeo.com/284616898

https://vimeo.com/284616919

With that body, cruising speed was about 21-22 mph on flat ground, top speed somewhere around 33-35 mph.



I'm working on a more streamlined body shell and hope to top out at 40 mph on flat ground when it is installed.


Current configuration(weighing about 65 lbs with the body):

-x1 KMX adult-sized steel frame kit
-x2 Velocity USA 20" rims, 14ga spokes (front)
-x2 Gas Shocks (front)
-x2 Schwalbe Marathon Greenguard 20"x1.5" tires (front)
-x1 26" double-walled wheel with 12ga spokes (rear)
-x1 Schwalbe Marathon Plus Tour tire, 26"x1.5" (rear)
-x3 packs of KMC 3/32" anti-stretch 7 speed chain
-x1 DNP Epoch 7 spd rear freewheel cogset, 32-11T
-x1 Suntour XCT Jr. 22/32/44T front crankset with 152mm crankarms
-x1 Shimano Tourney 7sp rear derailleuer
-x1 Shimano Revoshift 7 spd shift knob
-x1 SRAM 3 spd shift knob
-x1 SunLite dual cable pull lever
-x2 Avid BB7 cable-pull disc brake rotors, calipers and organic pads
-Lights, cables, mirror, speedometer, ect.
 

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Discussion Starter · #16 ·
An update:











So far here's the realized specs:

-46 mph top speed on flat ground on a full charge with the motor enabled
-1,500W peak power, plus rider effort
-7 watt hours per mile @ 30 mph w/light pedaling
-9 watt hours per mile @ 35 mph w/light pedaling
-12 watt hours per mile @ 40 mph w/moderate pedaling
-12 watt hours per mile in the snow with enough effort to do 30 mph on flat ground, but riding at speeds from 20 to 40 mph with a 20 mph rolling average
-While powered yields a consistent 40-50 mile range with enough effort to cruise at 30-35 mph on flat ground in freezing weather. I get about 8.5AH from the 46.8V pack in the cold, although it is rated to 10.5AH. This should improve to perhaps 60 miles range at the same speed in warmer weather due to reduced air density and increased battery capacity.
-With the motor disabled, I can pedal it to 35 mph in a sprint and cruise on flat ground around 23 mph. I lost a few mph unpowered after installing the motor due to its additional weight and cogging losses.

I tend to cruise around 30-35 mph and my lifetime average energy consumption is about 9 wh/mile.

At any operating speed with which it is capable, it feels stable and tracks straight. It has been up to 60 mph downhill before I motorized it and felt stable. It is very controllable at 30-40 mph in 30+ mph crosswinds with 50 mph gusts, although one will need a bit of effort to keep it straight in those extreme conditions. The brakes are good up to about 35 mph, but after that they are questionable and require careful modulation.

Regarding what specs this will eventually have, I'm in the process of building another battery pack. It's going to be 72V 21AH, capable of delivering 5 kW peak, and is liable to give me a 150-200 mile range @ 30-35 mph, acceleration like a car(simulation shows 0-30 mph in about 5 seconds with a 96A phase current, but a better controller and a 150A phase current could allow 4 seconds), and a 70 mph top speed. I’m also going to finish a set of wheel fairings, a windshield, roof, and rear wheel cowling to cut drag further. I also plan to add brake lights, permanent running lights, headlight, and turn signals, as well as solar panels and a charge port for electronics. Later upgrades may also include hydraulic disc brakes, thicker brake rotors, and perhaps a rear suspension.

Here's some additional specs:

-Weight: 82 lbs
-CdA: Unknown
-Trike Frame: KMX framekit
-Body shell: Custom corrugated plastic bodywork with aluminum ribbing, mounts, and supports
-Battery: 46.8V 10.5AH pack of 13S3P Panasonic NCR18650GA cells, 490 Wh rated capacity, 1,500W rated peak power
-Motor: Leafbike 1500W 4T wind brushless PMDC motor, w/10k NTC thermistor and 10-12 awg bullet terminals, laced to 26" rear wheel w/13ga spokes and double-walled aluminum rim
-Controller: Phaserunner v3, currently set to 1,500W maximum power output, 750W maximum regenerative braking
-Computer: Cycle Analyst v3 DP, currently set to 1,500W maximum power output
-Charger: GrinTech Cycle Satiator HV model
-Torque sensor: Sempu 2-wire w/115mm spindle width, no throttle installed at the time
-Front wheels: Velocity 20" 32-spoke w/13ga spokes laced to double-walled aluminum rims
-Front tires: Schwalbe Marathon Greenguard 20x1.5" @ 95 psi
-Rear tire: Schwalbe Marathon Plus Tour 26x1.5" @ 60 psi
-Front crankset: Suntour XCT Jr. with 152mm crankarms, modified with 26/39/53T chainrings
-Rear gearing: SunRace 34-11T 7 speed cassette
-Front derailleur: Microshift Mezzo
-Rear derailleur: Shimano Tourney RD-TX35 7/8sp
-Chain: KMC Z7, lubricated with Boeshield
-Torquearms: custom KMX torquearm designed and made by EndlessSphere member dfwahl(left-side), GRIN Torquearm Kit v4(right-side)
-Right shifter: Shimano Revoshift 7 speed index grip shift
-Left shifter: SRAM 3-speed index grip shift
-Front suspension: EXA gas shocks on upper/lower swingarms at 65 psi, suspension designed and made by EndlessSphere member adam333
-Brakes: Avid BB7 calipers with 165mm disc rotors, cable-pull operated
-Right Brake lever: Terratrike dual-pull lever with parking brake
-Left Brake lever: GrinTech ebrake, operated for regenerative braking in the rear
 
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