electric side car technical question

[ke6cvh]

Hello,
Background: I am an American in the Philippines with my wife and triplets. I wanted to make an EV and that got me to begin researching the etrike program and it's flaws here in the Philippines. Bottom line is I think I've got a practical solution and working to build first prototype. Philippine tricycles are 125-150cc motorcycles with sidecars. The one I'll be buying is a new Honda MTX 150 that is final assembled in Batangas Philippines and has mounts already for trike. Trike will be custom/hand made as all usually are. I've also got a serious fabrication shop here with lots of tools and test equipment. Soon will have a speed monkey 5ft x 10ft CNC plasma table with hypertherm 65 as the showcase to shop and want to add powder coating soon also. Have the usual 3d printer and taig CNC desk top CNC mill also here.

Project specifics: I've been working with company in China to get an LiFePO4 battery pack here. That is the simple part as well as the controller. Battery will go under seat in side car. First was looking at a 60v 30Ah pack but leaning towards 72v now. Company sells 1500, 2000, 3000 hub motors and will mount in motorcycle wheel. Will mount the wheel on the sidecar making it an electric side car. Plan is to use as a hybrid. Motorcycle in gear only, motorcycle in neutral-engine off with electric only, both on as options.

Technical hurdles. All sounds pretty simple up to now. I will have to figure out how to mount controls on motorcycle handle bars so that I can have brake handle turn off of electric motor is first priority. After that need user simplicity while driving. Big problem in Philippines as the joke goes like this "how many people can you put on a jeepney or trike" answer "one more". So, in practicality if there are instructions to a driver to only load a few passengers so driver can use all electric on flat in the city and only both when battery is low or going up hills it may not be followed by desire to make more money etc. Specs on 3kw hub motor is 180kg road usage weight. Specs on 1.5kw hub motor is 160kg road usage weight. So my thought is to make a "dually" out of the tire on the side of the trike using two 1500 watt motors. The rest of the trike can handle the weight but the limit will be the hub motor and likely become it's Achilles heel. Tried to search all over the internet about what axles are made of etc. Any recommendations on how to make a dually type tire setup using two 1500 watt motors and two controllers running into a single wire coming off the throttle? The drop out is not a factor as this is a hand made unit that does not have forks on the side of trike. I could just smoke test it with a single 3kw wheel knowing that I won't be exceeding specs for personal use but it would be better engineered in the dually configuration and the cost of 1500w hub motor is almost 1/2 the cost of 3000w hub motor with a little better efficiency reported at 85% vice 82% or better (supposedly). Also, recommendations on how to run the controlling mechanisms off the handlebars would be great. I've already visited the DOE here once and would like to make a road trip from Batangas City to Manila via E-trike and present to both DOE and BOI (Dept. of Energy and Bureau of Investment).

Best regards,
Mike

 

[Drunkskunk]

Welcome to the forum.

This sounds like an awesome project. Have you considered replacing the motorcycle's main rear wheel with the hub motor? you could still use the gas motor to drive the wheel as normal, but the wheel would be more in line with the weight of the bike, and could be used more effectively for regen braking, and more effectively deliver power. A motor on a sidecar would be further out of the center line with the center of mass of the bike, and be difficult to control during regen, and cause the bike to want to turn when under power alone.

a twin motor can be done, and a dual motor/twin controller setup works well most of the time. But there can be complications. Small variances in component production means the controller's low voltage side that feeds the throttle may be a slightly different reference point between the controllers. when the throttles are wired together, sometimes they don't want to work together. There are a number of ways to solve that problem if it happens. Most involve opening the controllers. However, a dual output throttle could be built, that keeps the signals of each controller separate.
Its a semi-rare thing, but makes a single motor less complicated.

 

[buellfooll]

If I am understanding all this, you're saying two motors CAN'T run off a single, BIG, controller. Right? The newbie in me had a single controller planned for the two motors I'm building into my recumbent trike. Oh well! Time to break out the dual controller idea.