View Full Version : Hybrid Electrotrike MkII: Sneak peek

05-01-2010, 01:46 AM
After much fiddling and pissing about with the first version I decided a redesign was in order. This one is much better and I have already proven out the power train on the old version. This one also includes pedal power which should make it easier to pass scrutiny by the authorities.

The transaxle is from a lawn tractor and is all alloy case with excellent gearing for this application. It has a real differential and a 21 to one drive ratio with reverse, forward and neutral. The gas engine has a clutch so the electric drive can operate alone of the gas and electric can both provide motive power. Or, the transaxle can be in neutral and the gas enegine can recharge the batteries. Or, the gas engine can be in neutral and the electric can provide dynamic regenerative braking. Or, if all else fails the transaxle can be in neutral and you can pedal the thing. It pedals quite well as the rolling resistance is vey low.

The rear wheels are utility wheels with a 31mm bore (about 1.4") so there is plenty of room for a strong stub axle. The wheels, by the way, are made in USA. I also have some 3" fat tires to put on it which will make for a smoother ride at 35 psi (no suspension).

This design is about as simple as it can get which is one of the things I learned messing with my previous electric bikes. The electric motor is a rewound treadmill motor with custom made brush holders that have much higher ampacity. It can put out around 4 hp peak on 48 volts for several minutes and will run at 2 hp as long as the batteries will last without becoming more than just hand warm.



05-01-2010, 01:55 AM
Neat, Evan.

You are a bit ahead of your time, but the day is coming when we won't be able to afford to drive full size vehicles and we'll all want an electrotrike.

The Artful Bodger
05-01-2010, 03:30 AM
Good effort Evan.:)

05-01-2010, 07:02 AM
Hey Evan, you don't sleep, do you? Hehe! :p

Seriously, that's fascinating stuff, and I daydream at work about making such a contraption. I have a 17 mile country-road commute, and a trike like yours would be a perfect means of travel. May I make a suggestion for your next prototype? Recumbent trike!

05-01-2010, 09:02 AM
About the only advantage to me for a recumbent is that it would fit under logging trucks. It's too low for good visibility.

Here are a couple of more pics and a video of the electric drive under test on the much heavier MK1 prototype. It should go like stink on the MKII.




Tony Ennis
05-01-2010, 09:17 AM
Very nice as usual, Evan. Something like this trike would be awesome for quick trips about town.

and we'll all want an electrotrike

The problem with this statement which applies to any weight-reduced vehicle, is that there will always be a numnutz driving a 1964 Impala. Oh, and semis.

05-01-2010, 10:12 AM
Looks really neat Evan. I wonder how much load those rear wheels can handle since they don't lean like on a bicycle. Probably be fine if you don't drive it too wildly but some of the horseless carriage designs call for bicycle tires in the build and I have heard that they don't hold up too well under the side loads of cornering. They have been known to fold under when going around corners. A lot of the guys have to step up to bigger and stronger wheels like a motorcycle has.

05-01-2010, 11:00 AM
Evan: Looks like you used bolted construction for the chassis. Was this in the interest of prototyping. Welding would seem to maybe make a more solid frame.
Looks good.
I go 10 miles each day on country roads to coffee and this kind of vehicle is right up my alley.

05-01-2010, 11:24 AM

Those aren't bicycle wheels. The are special utility wheels designed for heavy loads which is why they have a 31mm through hole in the hub. They are sold specifically for trike use for that reason.
edit: Those aren't the final tires either. The ones I will be using are screwed to the rim with bead clips.

I don't have facilities to weld aluminum.

brian Rupnow
05-01-2010, 01:03 PM
Evan---Very nifty stuff. I wish we lived closer to one another. I love that kind of homegrown inventiveness.---Brian

05-01-2010, 03:17 PM
As usual, superb work. But how about some vital statistics, like what gradient will it pull up, and how fast will it go ? And will it get you up your hills with a load of scrap metal on the back ?

Is the gas engine quickly detachable, so you can leave it off for inspection, and pretend to the local constabulary that it's only there for heating in winter ? I think you'd have to go the full testing and insurance route if you did that on this side of the pond.

05-01-2010, 03:46 PM
As usual, superb work. But how about some vital statistics, like what gradient will it pull up, and how fast will it go

I will update that when it is fully operational. It is designed to pull at least a 15% grade. That is the main determining factor since the road up the hill to my house hits 13%. For this, what goes down must come up....

05-01-2010, 06:15 PM
It's looking good Evan.

it would be interesting, when you test, to compare how many units of charge it takes ...compared with how many litres of fuel it uses in separate tests...one or the other ...the same set journey.

I have a a few dc motors now, 24 volt and 12 volt, been collecting them....but often wonder if a small engine on its own would out-perform a battery only device as regards fuel /electricity consumption spend per mile....i have no idea..

This will work out different in different countries.

Electricity here is roughly 12.6 pence per unit.....petrol now 1.22 a litre..thats 5.53 a UK gallon ..or $8.44 a UK gallon

Because you Evan, can have one or the other running....you could be able to measure the difference...see which is the most efficient....in money per mile terms ..or units or litres per mile, so we in the UK can work out what our own results, would be if we decided to build one.

Yes, I know yours is duel hybrid and runs on both or single source motor during the same journey and will have regenerative braking..but I say, I for one, would be very interested in the results of one or the other test first...so we have a default to work from.

all the best.markj