Finished Electrom2.jpg
Hey everybody, I think Iím finally ready to show you all the project that Iíve been pursuing for the past year (not counting the three previous years of drawing and re-drawing plans. Iím calling it an Electrom. I built the frame and body from scratch to create a vehicle with a specific set of characteristics I wanted based on research Iíve done over 14 years. This is the 4th electric bike Iíve built, and incorporates a lot of lessons learned in that time. Not to say that all of that time was spent building bikes: life, jobs, and kids do take time as well.

I thought the memberes of this forum would find the Electrom interesting because it is basically a low powered electric motorbike that happens to have pedal and a recumbent riding position. The frame geometry would be very well suited to a higher speed vehicle, and if one were to eliminate the pedal-generating system there would be room for another 40 AH of 72 volt batteries.

The Electrom runs a 72 volt 20AH battery, a 40 amp Grinfineon controller, Grin Cycle Analyst, and 10Ē QS hub motor with a 3.5 inch tire to make a 17Ē diameter wheel. It is piloted via understeer handlebars connected to the fork via an aluminum and carbon reinforced control rod. The wheels, breaks and front fork are spec for a Tag 500 Ebike, a type of electric scooter/bike sold in here in BC by KGís cycle. It has hydraulic disk brakes, regenerative breaking, mirrors, lights, break lights and turn signals. There is a front fairing and a back tail-box with an easily detached cargo hatch for the carrying of passengers or large cargo.

One of the most novel features of the Electrom is that the riderís pealing energy goes into an on-board generator made from a small DD hub motor. This allows the rider to pedal at a constant cadence regardless of the speed or terrain, it also means you can keep pedaling while coasting to a stop or going down hill. The result is that the rider doesnít have to think about gears, and your quality of exercise is greatly improved. In order to comply with legal ebike definitions, and to have some human energy available when a hill is too steep for the hub motor. Iíve designed a system where the riderís pedaling energy is split between driving the generator and driving the back wheel via chain. The chain from the riderís cranks goes down to a hub, where there is a cog that connects to the back wheel via chain, and on the other side of the hub thereís a 54 tooth #25 chain sprocket that drives the generator hub motor. The gear ratio for the back wheel drive is very low so that as soon as the vehicle is going over about 5 kph the back drive starts to freewheel. This is might sound like a complicated system but it is actually pretty simple. In addition to satisfying the legal definition of an ebike, it also means that when you encounter a really steep hill you can help the DD hub motor out with your leg power. The main benefit is simplicity of operation. The rider can just pedal at a constant cadence with constant resistance and no need to shift gears to match the vehicles speed.

The top speed at 84 volts is 55 kph, but the fastest I can legally run it here in BC is 32 KPH. I keep my top speed limited to 40 KPH and here in the city of Victoria BC I have been riding it for the past year with no hassles from the police. I think that they see that I am clearly peddling and that makes it ok by them. I hope that we can convince the BC government to allow a top speed of 42KPH similar to California, as Iíve found around 40 KPH to be the sweet spot in terms of getting where I want to go fast enough and having a decent range. The goal in creating the Electrom was not to build some kind of overpowered cheater vehicle, but to make something that tries to fit the legal definition of a bicycle while achieving as many of the conveniences of a car as possible.

Range at 32KPH is 80 kilometres, at 40KPH about 50 kilometres, and at the top speed of 55KPH Iím lucky to get 35 kilometres. I find that for most of my use in the city I charge the battery to 80% and never run low as most of my trips are short. There is room on the frame for another 40 AH of batteries when I can afford them. Most of the time I run the controller with a 1800 W max as I find this to be the sweet spot between acceleration and range. Thanks to the position and aerodynamics of the fairing the bike can easily maintain 40 kph on the flat using 500 watts or less

The body panels and tail-box are all easily removable for access to the inner working or to change a flat tire on the rear. (but with the big scooter tires and tire sealant Iíve not had to deal with a flat). I have also made up a fixture I can mount on the tail-box to allow me to carry my MT bike out to our local MTB riding area. The tai-lbox cargo area is very spacious and easy to access.

Rationale

I believe that what most people really want is convenience; By ďmost peopleĒ I donít mean the users of this forum, weíre all sprocket heads who are willing to deal with mechanical complexity. ďMost peopleĒ are the folks that never got out of their cars in the first place because they see the car as more convenient. In oder to convince a few more of these folks to ditch their lane-hogging 5 passenger cars the alternative needs to offer some advantages.

The design of the Electrom is based on the premise that while it legally qualifies as a bicycle, it is not really a bicycle. To my mind a bicycle can be carried up stairs and stored in your apartment, a true bicycle can also take advantage of intermodal transport solutions like the bike racks on city buses. By that definition the Electrom is not a bicycle. My thought was that there could be another form of vehicle, somewhere in-between a bike and car, and that if we desperately cling to all aspects of a bicycle in our ebike designs we will be unable to truly innovate. The Electom is easy to get on and off of, immune to traffic jams because itís a ďbikeĒ, can be legally parked wherever a bike can go, is able to carry a lot of cargo. It has some protection from the elements, is highly visible and therefore safer, and allows the user to pedal as little or as much as they want. The Electrom offers things that a conventional bicycle can not, but to do so you have to give up the lightweight simplicity of a conventional bicycle, but then most ebikes have already given up many of those features already.

I also wanted to see if I could use electrification to solve some of the recumbent bicycleís inherent flaws (hard on hills, too low to be seen and therefor unsafe) and to see if the recumbent position could help with one of the biggest challenge to e-bikesĖwhere to put all that battery weight. Along the way I realized that I was building a completely new class of vehicle (kind of a grandiose statement I know). This is not a bicycle, Motorbike or car, but a kind of velomobile ( but not one you need to be a contortionist to get into). itís widest point is the handlebars, this allows the user to take advantage of the gaps in traffic that a bicycle is entitled to use in most jurisdictions. Itís pretty long, and needs to be in order to fulfill itís other design requirements, but slipping through traffic easily is more about width than length.

The Electrom will not be for everybody, itís a two-wheeler and so the rider has to be comfortable with that. Slippery road conditions can be tricky, and most batteries donít like being cold, so itís not an ideal Northern-winter vehicleĖit wants the same riding conditions as a motorcycle.


Construction Techniques
I built the Electom from scratch using carbon fiber, kevlar, fiberglass, aircraft epoxy, 1/8 aircraft birch plywood, hickory for bolt points, and aluminum. If one were to mass-produce the vehicle you would not build it this way, but these were materials I could work with in my limited shop, and they offered flexibility of design, which I wanted for a prototype build like this. The welded aluminum swing arm I had a friend help me with in his better equipped shop.

The design is basically a monocoque with large access holes to fit batteries, controller and other components. I did my drawings in Adobe Illustrator (Iím a graphic designer by trade) and while Illustrator is not a mechanical design program, I found it to be sufficient. I think it helps that Iíve been thinking about this design for so long that I pretty much had a 3D model in my head. One handy part of drawing it in Illustrator was that I did the drawings at full size, and was able to have large paper template sheets printed out for my cut-out plywood& carbon shapes.
Electrom Build1.jpgElectrom Build4 out of the bag.jpgTailbox 2.jpg


Riding Characteristics
The Electrom is a big vehicle when compared to a bike, but it handles pretty well. It is fully suspended and has 3.5 inch tires so bumps and potholes are not a problem. It definitely handles slower than an upright bike and this takes some getting used to. It can really carve the turns though. I find that for most riding I relax with my back against the seat, but if I want to negotiate a series of quick turns I just pull my back away from the seat back and this allows me to steer more with my hips, kind of like slalom skiing.

One unexpected benefit of the high-pedal long-wheelbase and generator drive is that you can pedal all the time, even thought corners as there is no danger of your pedals striking the ground. The LWB and full suspension also makes it easy to keep your feet on the pedals over bumps. In fact Iím just riding a set of cheap plastic pedals and my feet never fall off.


The range depends on the speed I go and the wattage the controller is set at. At 1200 Watt Max and a top speed of 32 KPH I get about 80 kilometre range. At 1800 Watts and 40 KPH max I get about 50 kilometres. At 2800 Watts and 55 KPH top speed I get about 35 kilometre range. The top speed for this build of the Electrom is 55 KPH but it the design could easily handle more speed. I had itís predecessor, which used a larger diameter rear wheel, up to 90 KPH and it was very stable at that speed.


Summary of the Electromís Features:

Generator Drive - The generator drive acts like an automatic transmission for a bike. The riderís energy goes from the cranks to a hub that sends it to both a generator and the back wheel via a chain drive. As soon as the vehicle exceeds 5 kph the chain drive is in freewheel mode and all of the riderís energy goes to the generator. The rider is free from the need to shift gears and can just pedal at a constant cadence producing electricity. An average fit person can generate about 150 watts continuously. It is true that this is not the most efficient use of human energy, but when the vehicle can put out up to 2800W there is not much point in obsessing about how efficiently you use the average riders 200W.
Electrom Pedaling Station.jpg

Ease of use - the Electrom has been deigned from the ground up to be easy to use. Stand-over height is just 17 inches and thanks to the swing-away front fairing, easily deployed center-stand and understeer handlebars, getting on and off is super easy. This combined with the fact that there are no gears to shift through make for a very pleasant riding experience. It also has mirrors, lights, turn signals and a quick-deploy centre stand, all of which make it easier to use.

Slips through traffic -
The Electrom is legally a bicycle, and as such is allowed to lane-split. This and the fact that the widest part of the Electrom is itís handlebars at 27 inches, allows the rider to easily get past stalled traffic. Itís motorcycle grade tires are stable and safe at speed and make riding on the shoulder of the road where all the sewer grates, debris and bumps are much less nerve racking.

Cargo and passengers - the back tail-box has been designed to handle cargo (up to five grocery bags), and with the easy removal of the cargo hatch it has room for a small adult passenger.

Clean appearance & no greasy chain - The electrom is mechanically simple and the majority of the mechanical components and wiring out of site under body panels. The Panels are easily removed for maintenance. The drive chains are all hidden away where they canít stain the riders clothes

Great visibility - The Electrom is safer in traffic than most recumbent bikes because the higher rider position puts the rider at eye level with other road users. The vehicleís size also makes it much harder to miss.

No hard-to-find parts -
While the design of the Electrom is different, it uses as many off-the-shelf parts a possible in order to keep manufacturing and repair costs down.
Finished Electrom1.jpgFinished Electrom3.jpgFinished Electrom4.jpg

Some of the Questions Iíve had so far

Why not a trike?
I had several reasons for sticking with two wheels; 1. I like carving through turns; 2 one of my main design goals was to keep it simple, and a trike is by nature more complicated, 3, vehicle width and aerodynamicsĖas I knew I wanted a high rider positions it would have had way too much frontal area as a trike. Also, a trike is much wider at the pavement, which means that if your occupying a 48 inch wide curb lane with your 36 inch wide trike you only have 6 inches between your wheels and the curb and the the vehicle next to you. On the Electrom my vehicle width at the pavement is only 3.5 inches so I have much more room before I have to worry about my tires scrubbing up against the curb or the cement truck in the lane next to me.

What if your electrical system fails, can you pedal it home?
Not really. There is a single low speed connected from the pedal to the back wheel, but heaven help you if you actually tried to use it by itself. But then you donít expect to be able to push your broken car or motorbike home either.

Why not use a mid-drive?
You could definitely use a mid drive on a vehicle like this if you wanted to, I opted for DD because I wanted to make operating the vehicle as simple as possible, and I wanted the re-gen breaking as the vehicle weighs close to 100 lbs.

Do you get a lot of questions?
I sure do, and almost all of them are really positive. People are very excited when I finish explaining what the Electrom is and what it can do.

So, whatís next?
As I said, people are pretty excited by the Electrom and I have had several offers to purchase it outright. I am considering some kind of crowd funded campaign to produce a kit version of the frame, body panels and tail box.