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Post up a thread for your EV. Progress pics, description and assorted alliteration
jpcw
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Post by jpcw » Sun, 29 May 2011, 17:21

Ok am I nuts?

I’ve decided on my next project. Probably a bit premature as I haven’t finished this one yet :)

I have always though the best way to do an electric vehicle is to start from scratch but the regs on building a car would make it next to impossible. However after going through the NCOP15 Trike Guidelines (http://www.infrastructure.gov.au/roads/ ... an2011.pdf) it looks like a fully custom build 3 seater Electric trike would be achievable. Even have up to 1 tone to play with so battery capacity should be easy with lithium’s.

I was thinking of using something like kellycontrolers dual hub motor kits as the drive system (http://kellycontroller.com/72v-dual-car ... p-723.html or http://kellycontroller.com/96v120v-dual ... p-810.html)

This would be a long term and most likely expensive project as I don’t plan on cutting corners with it. I have a friend who owns a steel fabrication business so the body work should actually be quite easy.

Maybe something a bit like this
http://www.national3wheelers.org.au/mem ... 20089.html

So back to the original question. Am I completely nuts? :)
“The best way to predict the future is to invent it,” Alan Kay 1971

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Post by Electrocycle » Sun, 29 May 2011, 17:31

jpcw wrote:Am I completely nuts? :)
yes!

But you are not alone :P

viewtopic.php?t=1691
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Post by jpcw » Sun, 29 May 2011, 21:36

Thanks, Very interesting (and long) read.
The hub motors will probably be way underpowered and a lot slower in comparison but might make suspension and space a bit easier to deal with.
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Post by EV2Go » Mon, 30 May 2011, 00:09

Why did I have the funny feeling I would be at the other end of that link Image
There are definitely easier ways to do it... but I still believe building one from scratch is a good idea.
If you are trying to do it on a budget there are certain steps I would recommend giving a miss. Just buy the front end off a second hand big bike, trying to piece something together yourself can be expensive.

Edit: This will probably give you a better idea of where I'm going with it... http://www.evalbum.com/3343
Last edited by EV2Go on Sun, 29 May 2011, 14:15, edited 1 time in total.

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Post by jpcw » Mon, 30 May 2011, 18:34

Thanks Paul,
Not too worried about budget (within reason). I'm going to try and build as much myself as possible, may get pre maid forks though. The idea is to build something that I can do up a good set of plans and then duplicate again without having to worry about obtaining different second hand equipment.
The Trike will be licensed with category LEP1
Motor Tricycles, to which these Guidelines apply, are defined in the ADRs as follows:
Motor Tricycle (LE): A motor vehicle with 3 wheels symmetrically arranged in relation to the
longitudinal axis, with a Gross Vehicle Mass not exceeding 1.0 tonne, and either an engine
cylinder capacity exceeding 50 ml or a Maximum Motor cycle Speed exceeding 50 km/h.

LEP1 - over 450 kg Unladen Mass and/or the driver’s Seat is not of a saddle type and/or has more than two seating positions and/or has a permanent structure to the rear of and 200mm above the undeformed upper surface of the driver’s Seat cushion and one wheel at the front, 2 at rear.
Just got some specs on the wheel motors,
It is around 60lbs (~27kg).You may not apply above 700KG load for one single car hub motor.
The hub motor has 28 pole pairs.
The resistance is 13.6mohm.The inductance is 0.03mH.
So they should be able to spread the max weight of 1000kg across the two which was my first concern. Not that I’m planning on making a 1 tonne trike but at least I know what my technical limits are.
“The best way to predict the future is to invent it,” Alan Kay 1971

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Post by EV2Go » Mon, 30 May 2011, 19:51

I'm aiming for LEM which is sub 450kgs. If memory serves me right with LEP you had to have a windscreen and wiper and more ADRs... While I don't necessarily believe every decision I make is the right one (lol heck I’d be happy if one of them was) there are very good reasons I decided on LEM.

Let’s give some serious thought to the front end for a moment... if you start loading up the front end with massive weight, you are more than likely going to pop the fork seals right out of the forks. Even the big touring Harleys, Honda etc don’t often cross a 1000lb (446kgs) threshold.

Some of the big bikes DO have issues with fork seals caused by excessive front weight. The problem is you can’t just move the weight backwards, as you need to maintain a certain balance for the braking to work properly.

The solution.... (at least my preferred version of the solution) is a girder front end. The entire load is taken out of the shock tube and placed externally (allowing for better load bearing, and less fork deflection). There is also an added benefit of being far superior suspension design to many other suspension types. While the latest inverted telescopic tube fork may look great on your Jap pocket rocket, it is actually an inferior design to something made nearly a hundred years ago.

The issue is as altering rake and trail, for suspension to work well you want it to be consistent across all conditions. When you brake hard on all modern telescopic bikes the suspension dives and alters the trail sometimes quite dramatically, not to mention the effect on the rake angle.

The sheer simplicity of the girder is obvious when you look at its design, instead of the wheel coming towards the rider like a telescopic, the wheel travels in a near vertical plane, leaving the trail almost unaffected.

I bought some plans on DVD from the US a while ago if you would like a copy of them (license agreement allows for limited non commercial distribution).

The other thing you might want to consider is you don’t have a seat belt on... so you hit a bump and do a big high side, how much weight do you want chasing you down the road?

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Post by EV2Go » Mon, 30 May 2011, 19:59

I realise the advice I just gave contradicts what I said earlier but it comes down to weight, if your contemplating a real light trike on a budget, buying a front end off a big bike is the way to go. If budget is not so much a consideration OR the trike is going to be heavy then I say build your own.

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Post by EV2Go » Mon, 30 May 2011, 20:13

I quite like the Duolever (mainly because it isolates the steering from the suspension), but it would take considable more fabrication... I did think about this one for a while.

Edit: while this ticks all of the boxes I am sure the potential weakness is obvious... any wear in either the top or the bottom ball joint is going to give the wheel plenty of opportunity to wobble. While a small amount of wear isn't a massive problem in the front suspension of your car. A single front wheel wobbling is a big deal.

Image
Last edited by EV2Go on Mon, 30 May 2011, 11:27, edited 1 time in total.

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Post by jpcw » Mon, 30 May 2011, 20:53

Yes, I was actually looking at some of the pre made custom font end used in some of the larger petrol trike kits. I'll get a link when I get home
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Post by Richo » Mon, 30 May 2011, 21:09

jpcw wrote: Ok am I nuts?

Only if you think you can do it but can't really.

How does your 2xBLDC's compare to a BMW diff and a small series DC motor?
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Post by EV2Go » Mon, 30 May 2011, 21:36

One thing I would probably reconsider in hindsight is the diff... I detest chains with an intense passion, hense why I opted for a diff. But if I was to do it all over again I wonder if I would go with a belt version of this.

Some serious sway bars are required if you went IRS, as trikes do not handle the same as cars with IRS. Better yet a system that leans into the corner...

Hmmm just gave myself some fresh ideas for the tilting trike Image

Image
Last edited by EV2Go on Mon, 30 May 2011, 11:38, edited 1 time in total.

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Post by jpcw » Mon, 30 May 2011, 21:37

Main reason for the 2 motors is to make independent suspension simpler and to give a bit more space without having to worry about a diff and onboard motor. Going to be some drawbacks such as high unsprung weight on the wheels, possible a bit less efficient, lower top speed (don’t fancy doing more than 120kh in a trike anyway, unlike EV2go Image ). I may have to work on an “electric diff” but that should not be too hard if I’m using 2 controllers. It will need some tuning to get the two motors running at the same speed/power in a straight line but can probably do that with a simple adjustment pot on one of the controllers
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Post by EV2Go » Mon, 30 May 2011, 22:00

If you combined this with the one above... IRS without the penalty of diff gears.

Image
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Post by jpcw » Tue, 31 May 2011, 00:11

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Post by EV2Go » Tue, 31 May 2011, 01:28

ok I thought you were talking about something like this

If you are going to use regular car wheels like me I think you would be better off putting two electric motors back to back in the centre and run drive shafts to the wheels.
Last edited by EV2Go on Mon, 30 May 2011, 15:29, edited 1 time in total.

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Post by jpcw » Tue, 31 May 2011, 02:27

No more like this
Image
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Post by jpcw » Tue, 31 May 2011, 02:29

EV2Go wrote: ok I thought you were talking about something like this

If you are going to use regular car wheels like me I think you would be better off putting two electric motors back to back in the centre and run drive shafts to the wheels.
That is what I was effectively trying to achive with the hub motors. Doing it that way the motors do not take up any room on the main frame leaving a lot more space for batteries and suspension.
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Post by EV2Go » Tue, 31 May 2011, 03:42

Thought that idea sounded familiar
EV2Go wrote: They would have their place in limited applications. Lets for a moment say I built my trike using two hub motors, the whole area taken up by the motor / diff could be filled with batteries lowering the COG.

But agree for the average car conversion it is far simpler to use a motor / diff.

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Post by jpcw » Tue, 31 May 2011, 03:57

Probably where I got the idea from ;)
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Post by Richo » Tue, 31 May 2011, 06:13

Ok I agree the hub motors will be better for room on the frame.
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Post by EV2Go » Tue, 31 May 2011, 17:14

Just trying to think why I don't like the idea... lack of braking maybe??? otherwise it does seem quite logical.

What if you used a flatish pan motor on each side and bolted it to the outside of the battery box / frame (insert motor in a cut away), the bulk of the batteries could still be positioned in the centre with a low COG.

Or maybe something like a angle grinder, a long thin motor running front to back on the outside with gear to change directions.

Or 2 long thin motors (6.7") end to end across the trike wouldn't impede much on the batteries...

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Post by jpcw » Tue, 31 May 2011, 17:20

The hub motors do come with disk brakes plus regen braking.
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Post by EV2Go » Tue, 31 May 2011, 18:00

Apart form the unsprung weight it really is hard to fault the idea... I personaly don't like the two motors driving different wheels, but really hub motors are such a logical choice for a trike, I think this has the makings of a very interesting project.

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Post by jpcw » Tue, 31 May 2011, 19:10

Actually I think I might have some fun and try to implement a power assisted steering system by independently adjusting the speed of each motor. Might come up with the first all wheel steering trike :)
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Post by EV2Go » Tue, 31 May 2011, 19:10

Just looking at the website where you got this... a number of them are using girder front ends, while others are using springers. This is a leading link. Makes me feel better about my choice now.

Image

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