24v Etrike using a wheelchair drive system
Left is before the bracing was completed and to the right with bracing secured.
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Each string of LEDs demands 24v @20ma. As such each light string has 24 super bright LEDs. For the marker lights, there are 8 at the front, 2 groups of 3 on each side and two groups of 5 at the back all wired in series.
So our front wiring is established. From the left handlebar we have 8 22ga wires to the front controller. From the right handlebar we have 5 22ga wires to the controller. The front lighting will mount later to the front of the control cabinet and it's 15 wires directly connect into the cabinet. 8 18ga wires, 8 22ga wires pass from the control cabinet to the electrical compartment. Thats 16 wires that have to pass from the center of the handlebars to the rear frame.
Electric Wheelchair Mid drive system: 24v system
The original wheelchair scooter had two motors to move a mass of about 700 lbs up to 8mph. It used direct drive of each wheel independently. Of the 700 lbs, there was provision for a 300 lb occupant, 2 x 85 lb batteries, and a frame of about 230 lbs. Each motor had a park brake such that when no power was going to either motor the wheelchair was difficult to attempt to be moved. Joystick control provided forward or reverse motion and steering by regulating power applied to each motor. The range as stated in the specs was 8mph maximum for up to 10 hours per charge. This equates to a 40 mile round trip.
The first consideration in using a wheelchair motor in an E-Trike has to do with the rare earth Magnet that allows the motor to almost totally prevent motion of the wheelchair when power is not applied. Great Idea for a wheelchair's safety but a hindrance in a an E-tricycle application. Firstly, this motor brake will stop the motor but do nothing to stop the freewheeling rear wheels. Secondly, it takes a lot of power from the battery to constantly hold the brake off so we can move. So step one is to remove this brake (and due to the strength of the rare earth magnet you can do serious harm if you get your fingers in the way of it trying snap back in place.
Our Etrike framing is about 160 lbs with 250 lbs occupant and anticipated storage of up to 160 lbs. With lithium batteries (80 x 0.32 lbs) we have only 24 lbs. Our overall mass is 100 lbs lighter when fully loaded and 260 lbs lighter when the basket is empty. 2 motors depleted 35 ah battery at full load in 10 hours on the wheelchair. Clearly 1/2 of the power was used to keep the brake off. Assuming 2 motors moving 700 lbs forward motion only, each motor can easily move 350 lbs. 8mph on 10 inch wheels is 268 rpm, but, and there is always a but, at 1:2 axle ratio and 24 inch wheels, we have 536 rpm for 38mph.
Several changes must be done to the original plan. Battery pack has to change from 15 series cells by 5 cells parallel to 8 cells series by 10 cells parallel (double the capacity) going 24v from 48v. Solar charge goes from 57v @4ah to 30v @6ah (faster charging). The axle system needs 2 x freewheel sprockets up from a single sprocket. Lighting has to be changed from 48v to 24v. The charge / inverter has to be changed also from 60v to 30v, and a custom controller is needed. The wheelchair controller had forward and reverse, two motor control and now needs forward only single motor control.
The driveline system:
We have already talked about the need for two freewheel sprockets on the axle and used one for the Chain crank gear. Now we need to mount the wheelchair motor under the basket in line with the second freewheel sprocket.The Drive Axle
Electric Wheelchair Motor Mid-Drive
A typical motor is a brush type DC motor with 5400rpm maximum (short term) and 4800rpm (maximum sustained). The motor drives a worm gear transmition to a wheel axle plate. The basic ratio is 18:1 which provides 268 rpm at the axle. Applying any power to the motor forces a rare earth magnetic brake to release. By mounting a drive sprocket of 7" to the wheel mount studs we have a ready made forward drive system. Now the motor can be driven either direction, but since we are using freewheel bearings only one direction results in motion. Spinning the motor in the opposite direction might have use if we used another freewheel bearing and axle to implement braking.
Electric E-Trike controller
The heart of the Electric Trike is the control unit that fits in the back Electronics bay on the right hand side. On an E-Bike it is both the heart and brain but, and there is always a but, this is a super E-Trike. As a super E-Trike the controller takes direction from a brain called the Main controller. The main controller handles E-Trike drive, Lighting, braking, AC charging, solar charging, and power Inversion. So in this case, the E-Trike controller is powered from Main controller. The Key lock wiring of the controller can be bridged or wired as a secondary key switch. The throttle takes 3 wires and two sets of 2 wires run to the brake handles as motor cut-out switches.
Windshield & Containers round up the finishing.
For this Tricycle project there comes a need for custom containers for Batteries, Controllers, and the Windshield itself. Poly carbonate (Lexan) or Acrylic (Plexiglas) are the go to resources that can accomplish this. While we can make the containers using 3D printed forms, the lack of a 3D printer and CAD skills makes it more prudent to go with plastic sheeting which we need for the windshield anyways. Below is my research in such plastic sheets.
Bill of Materials
| Section | Item | Estimate$ | E-Total$ | Actual$ | A-Total$ |
| Basic Trike |
bike 1 bike 2 bike 3 |
$0.00 $100.00 $100.00 |
$200.00 |
$0.00 $9.98 NLR |
$9.98 |
| With the changes along the way I was able to acquire 2 donated bikes and reworked the design such that only 2 bikes were needed. The front 26" wheel is changed to a 26" electric hub wheel. The other bike had 24" fat wheels and became the rear wheels. One of these wheels needed a new tube. The first bikes 26" wheels became the wheels for the trailer. | |||||
| Trike Framing |
0.5" x 48" Sq Steel Tubing (25) 20ga Metal skin () Welding $2/joint . . . 120 cut brackets Compartment Locks (6) Piano Hinge (8ft) |
$160.00 $230.00 $120.00 $36.00 $12.00 |
$558.00 |
$195.00 $0.00 $42.00 $0.00 $9.00 |
$246.00 |
| Building the frame took considerable reworking. Firstly, the .5" square tubing got changed out to .75" square tubing, and instead of getting 25pcs x 48" I only received 23 pcs cut to almost exact lengths. Welding was replaced by 120 cut .5" x 1" 'L' brackets and 480 rivets. | |||||
| Driveline |
1" x 48" Steel Rod (1pc) 1" Pillow Bearings (2pcs) 1" sprocket hub (3) 16T 3" Freewheel sprockets (2) 15T Sprocket Chain (15ft) |
$8.55 $25.18 $16.00 $26.00 $15.48 $50.00 |
$157.21 |
$38.95 $25.18 $16.00 $26.00 $15.98 $0.00 |
$122.21 |
| The steel rod was much more expensive than planned. We are only driving one rear wheel instead of both so sprockets become 2 not 3 and the existing chains are resized to work. | |||||
| Brakes |
Brake F Caliper Brake L Caliper Brake R Caliper Servo |
$26.00 $26.00 $26.00 $26.00 |
$104.00 $1019.00 |
$0.00 $0.00 $0.00 $26.00 |
$26.00 $404.19 |
| A little reworking and I was able to reuse the brakes from the donated bikes to facilitate the braking of the three wheels. The front brake remained unchanged. The former rear brake of bike one became a transfer caliper on the center mount frame. The transfer caliper then fed the two rear brake cables such that when the rear brake is applied it pulls on the middle caliper which in turn pulls two brake cables to the rear wheels that use the brakes from the second bike Now with electric braking the front brake cable to the center is gone as is the middle 'Y' caliper to be replaced with a pivot and servo. | |||||
| Lighting Ctrl |
(1) DPDT-co-sw Paddle switch (1) SPST-mom Horn Sw (2) Push on/off haz/hlight (1) IC 555 timer ic (1) socket 8pin dip (1) PCB Perfbrd (1) Tr1 2N2222A (1) vr1 100k (2) rly1,2 SPDT Relay (2) r1,2 1kr (1) r3 12kr (2) r4,5 470R (1) c1 1uf (1) c2 .01uf (4) diodes 1N4148 (1) Projectbox (2) Pheonix screw terminal 8p (1) HBAR MNT PWM Brake: (1) IC 555 timer ic (1) socket 8pin dip (1) IC ILQ2 optocoupler (1) socket 16pin dip (1) diodes 1N4001 (2) diodes 1N4148 (1) resister 10KR (2) resister 100KR (1) resister 10R (1) 5v zener (2) 100uf (1) 10uf (1) Phoenix PCB screw terminal 2p (1) 2p header male (1) 16p header male (1) Key switch (1) Rly3 spst CylonEye: (1) 74ls73 jk Flip-Flop (1) 74ls191 4 bit up down counter (1) 74ls154 16 line demultiplex (1) socket 14pin dip (1) socket 16pin dip (1) socket 24pin dip (13) LED's |
$6.99 $3.65 $7.30 $0.75 $0.72 $2.50 $0.57 $0.25 $5.49 $0.40 $0.20 $0.20 $0.69 $0.69 $0.06 $12.00 $3.59 $3.55 0.75 0.72 1.14 0.72 0.10 0.30 0.20 0.40 0.20 1.60 1.12 0.69 1.42 0.20 0.20 15.00 2.43 $1.52 $1.52 $3.95 $0.72 $0.72 $0.72 $2.47 |
$100.79 |
$2.99 $2.29 $4.58 $0.49 $0.15 $ $ $0.15 $5.40 $0.10 $0.05 $0.10 $0.39 $0.39 $0.00 $0.00 $3.59 $0.45 0.75 0.72 0,00 0.72 0.10 0,00 0.20 0.40 0.20 0,00 1.12 0.69 0,00 0.20 0.20 2.43 $1.52 $1.52 $3.95 $0.15 $0.15 $0.15 $2.47 |
$38.76 |
| Lighting control reworked into a windshield mounted unit at handlebars with only turn switch at left handle grip. | |||||
| Lighting |
(1) Headlight (2) Tail lights . . . (208) LEDs . . . PCB stock for 6 displays . . . Epoxy case (2) Turn Light . . . (80) LEDs have 11 of 80 . . . Epoxy case (4) Marker . . . (16) LEDs . . . Epoxy case |
$11.00 $15.58 $6.46 $1.14 |
$34.18 |
$11.00 $15.58 $ $4.00 $6.46 $4.00 $1.14 $2.00 |
$44.00 |
| Purchasing a high luminous LED headlight and creating custom signal and tail-lights made more work but made for a unique and less expensive solution. | |||||
| Accessories |
Helmet Horn Mirror Windshield . . . 24" x 36" Plexiglas . . . 4 Electrical Conduit Clamps - plated (Select size to fit on the forks and/or handlebars) . . . 2 feet 1/4"-20 All-thread Rod - plated (struts) . . . 4 1/4"-20 Acorn Nuts - stainless steel or chrome plated . . . 8 1/4" washers - stainless steel . . . 12 1/4"-20 Nuts - stainless steel . . . 4 Rubber Grommets - 1/8" ID, for 1/8" thick material. . . . 2 feet 1/4" dia. Black Shrink Tubing (to cover the all-thread rod) . . . 1 Inner Tube (to cut into pads to isolate the clamps from your forks and handlebar) . . . 1 yard Felt Cloth - synthetic or wool New Handlebar |
$45.00 $8.00 $9.00 $50.00 $15.00 |
$127.00 |
$45.00 $0.00 $0.00 $28.00 $ $ $15.00 |
$88.00 |
| We kept the mirror from the first bike, used a high db horn as part of the lighting control system, and made a custom windshield. | |||||
| E-Trike Convert |
24v 1000W Wheelchair drive Accelerate grips (2) Brake handles (1) Custom Controller |
$100.00 $30.00 $15.00 $45.00 |
$190.00 |
$ |
$190.00 |
| The E-bike front wheel kit consists of the wheel with embedded hub motor, controller unit, brake handles, key switch and monitor. | |||||
| Battery Pack 24v @60Ah 1728W 144km Range Wght 12 lbs |
(15x6) 3.2v 6A Cells type 32700 (30x3) Cell forms 2m x 8mm Nickel Strip Plexiglas case |
(90) x $9.63 = $866.70 (90) x $1.29 = $110.70 $7.00 $28.00 |
$1012.40 |
$ $ $ |
$1012.40 |
| The most expensive part of the project is the making of the battery pack(s) | |||||
| Electronics |
(2) Cell Logger . . . Changed to (1) voltage display up front . . . add (1) led voltage level up front (1) 1Charge 208B . . . (15) BD140 transistor $12.45 . . . (15) 20k vr4 pots $1.50 . . . (15) TL431 zr1 $10.65 . . . (30) 20k resistor $1.50 . . . (15) 1k resistor $0.75 . . . (15) LED's $2.85 . . . (15) 330R resistor $0.75 . . . (60) 1N4007 diode $17.40 (1) Solar Ctrl . . . 4k7-5w . . . 240R . . . TIP142 . . . (2) 1N4007 Diode (1) 48v120 Inverter . . . 2w10BD bridge rectifier . . . (6) IFR9540 Mosfet . . . (2) IFR540 Mosfet . . . (3) 1N4007 . . . (1) 1uf Capacitor . . . (2) 2N547 transistors . . . (2) .01uf Capacitor . . . (1) 120-60-625w transformer . . . (1) 12vRelay-10a contacts . . . (4) 470R . . . (2) 1KR . . . (9) 2pos pcb connectors (1) 120v48v Charger . . . 2w10BD bridge rectifier . . . (1) 1uf Capacitor . . . (2) .01uf Capacitor . . . (1) 12vRelay-10a contacts (1) EBike Ctrl |
was $6.04 now $4.60 and $1.20 $181.98 $34.96 $48.65 $24.95 incl |
$296.58 |
$ $ $12.45 $1.50 $10.65 $1.50 $0.75 $2.85 $0.75 $17.40 $2.15 $0.05 $2.74 $0.58 $1.48 $10.08 $3.48 $0.87 $0.10 $1.02 $0.20 $68.85 $6.90 $0.20 $0.10 $13.50 $1.48 $0.10 $0.10 $6.90 Incl |
[$174.77] |
| With our custom electronics we have better control over charging, distribution and monitoring. It also doesn't hurt to be a fraction of the cost. | |||||
|
Solar Array 48v 2Ah 96W |
0.5" U Channel 30Ft (112) Polycrystaline Cells 16ga Wire Tab wire |
$48.00 $48.00 $8.00 $8.00 |
$112.00 |
$44.00 $102.00 $8.00 $32.00 |
$186.00 |
| The solar array also under went some radical change. Instead of 3 panels with two folding over the first panel, I changed from 3 x 1'x 4' panels to 2 x 1.5' x 4' panels that fold up vertically behind the seat. The change means that 220 cells can be worked in to provide 4A of charge instead of 2A. | |||||
| Other |
Pop Rivets Class 5 Bolts (7) Primer (3 cans) Blue Paint (3 cans) Acetate glue Epoxy/ resin 8oz to 16oz |
$3.49 $4.67 3 * $6.95 3 * $6.95 $ $ |
$49.86 |
$3.49 $4.67 3 * $6.95 3 * $6.95 $ $ |
$ |
| $2956.42 | $2174.91 | ||||
Adding things up:
For a rough total of $2956.00for a full featured ETrike with a 144km range at 50km/hour. It will be basically maintenance free for a span of 4 to 5 years then may require $885.00 to go another 4 to 5 years. Not to shabby! 60 months for under $41.00 per month and 120 months (10 years) for under an average of $28 per month.
I'd say that is a far cry from using an ICE car for simple trip commuting at a monthly cost of $1000 per month for 5 yrs not including maintenance.
Who'd of thought transportation costs of $60,000 over 5 years could be done for $3000. Provide free travel without need for insurance, fossil fuels, and high maintenance charges which aren't included in this report. *** Added bonus : Environmentally friendly ***