Electric Trike on the Cheap





Introduction: Electric Trike on the Cheap

hello everyone. first of all thanks for all the question/comments on my electric bike build.  Now we go to the next level. An Electric Trike made on the cheap with an old electric wheelchair and a standard trike.

Step 1: Find a Trike. and Motor(s)

i picked up my trike from Craigslist for 50 bucks.  As for the motors and control box i got a broken power chair from a friend in exchange for some auto repair work.

also going to need a front sprocket from a donor bike pile.  the bigger the sprocket the faster the bike will go (horsepower permitting)

the wheelchair has all needed parts. motor, controller, batteries, and controls.

other bits are from ACE hardware.

Step 2: Mounting the Motors

this is the tricky bit.  i disconnected the chain from the pedals to hook the electric motors up to the drive.

connected into the 3 speed hub i have 3 gear choices  1st gear is 50% underdriven (more power for hills)  2nd gear is 1 to 1 and 3rd gear is 50% overdriven (for more speed)

if you dont have a 3 speed you can connect the motors straight to the chain gear on the rear axle.

since it is an electric powerchair with 2 motors and the gearboxes had a 5 bolt hub i went to ACE and got some couplers and dug up an old front sprocket from a donor bike.  placed the sprocket between the hubs and bolted the hubs together.


motors are mounted on a board that is attached to the bike by the brackets that held the basket on originally.

you want to mount the motor solidly because it is going to put out 3 or 4 times the force of an average person pedaling.

also make sure the sprockets are perfectly aligned. If they are not the chain will slip off.  

also make sure all bolts are on the bike frame or it can cause problems later on.  i built this with absolutely no welding.

Step 3: Mounting Your Batteries and Building You Motor Cover.

this is the 2nd time i have rebuilt this bike.  in the original build i placed the batteries over the motors making the bike very top heavy with little weight on the front tire.

in this build i placed the batteries as low as i possibly could on the frame and it handles very nicely.

batteries are heavy. find a good way to mount them.  i used 1/2 in particle board to make my battery boxes.

while you build your motor cover keep in mind that you will need to get back into it regularly for maintenance.  also you need a slot to engage and disengage the gearboxes.

most importantly the motors and power controller will need air circulation or they can overheat and fail.

i cut 3 boards for the verticals making sure they all matched up in height.  then put a large board on top. the boxed structure keeps the bike very rigid.

all of the wiring is pulled from the powerchair with no cutting or splicing.  make sure to zip tie the wires up and keep them away from the chain drive.

Step 4: The Throttle Control

since i am using 2 motors that are bolted to each other it is important that the motors operate at the same speed.  if you try to turn the chair's control stick to the left or right it will cause the motors to turn different directions (very bad) and the motors will rip themselves apart from each other.

i put a thin slotted board over the control stick that lets it only go forward and backward.  OR you can go to an electric power chair store and have them reprogram the control box.  but that costs money.

so after you have that sorted out.  mount your control stick to the handlebars where you can easily reach it.

the control stick i have has a charger port on it so i can easily charge the batteries.

Step 5: Riding, Limitations, and Other Stuff

riding an electric bike requires a bike helmet in CA.  the bike cannot go over 25mph.  also must have a continuous wattage of under 750 watts.

also in CA (Sacramento area) you cannot ride it on bike trails (American river bike trail)  must use bike lanes on streets.
use google maps. they have great biking directions.

any more power and u will need to register it as a M2 (motorcycle under 149cc or electric) which requires license plates.

this bike has a power output of 700 watts.  can reach 25mph very easily.

now the limitations of the mechanicals.

this bike does not go in reverse since it is hooked to a 3 speed hub.  if i need to make a fast emergency stop i can throw the throttle in reverse activating the coaster brake in the 3 speed hub.

if you need to back the bike up you can throw the disengage levers on the gearboxes.

make sure you have both gearboxes re engaged before you ride or you can screw up your hubs.

make sure the chains are tight on the gears.  no slack. but dont make it super tight or you will lose power due to the friction from the chain.

this bike can go about 25 miles @ 18-20mph on a full charge with no pedaling.  charges in 6 hours.

you will need to tinker with the drivetrain a lot till you find mechanical weaknesses and get everything aligned.

I now have about 300 miles on this build and have had 0 problems.

if you have any questions about the build feel free to ask.  i will keep posting any mods i have made to the bike.

Step 6: Finished Product

here is my trike after a little paint and a basket added.  i also cut some thin plyboard to cover gaps around batteries.

dont forget to add rear reflectors and a red blinking light so you can be seen by other drivers. and its the law to have them.

Step 7: By Popular Demand....

hello all.  here are some videos for ya.



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    is it possible to hot wire the controller to use a button instead of the joystick? i want to modify a power chair i have for this project but want to get rid of the joystick and just use one button to make it go. how would you recommend i go about this?

    I have the same trike but I have a treadmill motor wht kind of motor controller do I need

    That is a tricky question. Do you have any information about the motor? how many watts volts or amps it runs on?

    Hum! I will pass that along to my brother. He is thinking of building it for me!

    I love this! I think I could handle it!

    Thanks! I still have this bike and have heavily modified it since this build. If i had one bit of advice for you if you take this build on is to strengthen the front of the bike more.

    The frame on this bike ended up breaking just above the horizontal bar over the pedals. You should try to put in a brace going between the fork tube and the up post for the seat.

    If you plan to use this vehicle on public roads, check with your local jurisdiction for they may require you to have it registered and possibly insured.

    in CA if it is under 750 watts its legal. they treat it as a bicycle.

    750W? You lucky bugger. South Australia the limit is a pathetic 200W before it gets classed as a motorcycle and needs registration etc