Etek Project: Bike to Trike

[fechter]

What a monster

10 ga. should be overkill for individual tubes. You want the wire that bridges the spring to be super-flexible. I suspect that the discharge problems may be due to poor connection between cells. Increasing the spring force may help, but you need to be careful not to cave in the ends of the cells with too much force. There might be some conductive paste stuff you could put between cells to help maintain contact.

Not sure about the power supply. I blew one (different model) by back feeding it too much voltage and found there was a diode across the output terminals that fried. Does it register any current? You could open it and look for obvious charcoal.

Are you planning to use regen?

 

[steveo]

This thread is heaven; I've always wanted on eteck on a kmx; I'm waiting for your videos!!!;

oh and if you were near by; i'd request a drag race


p.s. I like the way your battery pack is fitting; but your design is going to haunt you; Take time to design your pack by placing cells in parallel and then series; by doing this you will highly reduce the risk of killing cells and there life span will be longer + you will be able to balance everything way easier. you should see my a123 cell matching thread; took me months but worth all the effort; be and doc did the same process.

here is 1 thread

http://endless-sphere.com/forums/viewtopic.php?f=14&t=3860&p=56795&hilit=+a123#p56795

-steveo

 

[TPA]

From your pics, it looks as though your copper bar is oxidized, but I can't see the other side.

If both sides are oxidized, polish the contact side to remove the oxidation and improve contact along the bar.

 

[safe]

I like the way your battery pack is fitting; but your design is going to haunt you; Take time to design your pack by placing cells in parallel and then series; by doing this you will highly reduce the risk of killing cells and there life span will be longer + you will be able to balance everything way easier. you should see my a123 cell matching thread; took me months but worth all the effort; be and doc did the same process.

I've built solderless tubes for SubC NiCads and they work great. I'm using a spring to make the pressure and then using copper contacts to do the actual conducting of electricity.

But steveo is right... you CANNOT load all your LiFePO4's in series like that. For NiCads you have to do everything in series because that's the way their chemistry works, but LiFePO4 needs to have things balanced on a cell by cell basis or you will get very poor mileage out of them. (the cells will die quickly)

I love the fact you are doing the solderless tubes (which will work) but it's the wrong chemistry for it. :|

Mindblowing project.... etek trike... wow.

 

[VRdublove]

Thanks for the positive responses guys!

It is an absolute blast to ride, with its lower center of gravity and gobs of power! I haven't yet mounted a bike computer, but I have achieved ~40mph as confirmed by the speedometer of a friends car who happened to be driving next to me.

The battery has been by far the biggest hassle of this whole project. I would like to add another 6 tubes before its all said and done to up the capacity from 17Ah to 25Ah. Before I ditch the PVC design, I'm going to try putting 2 or 3 balancing wires across the tubes so that there are only three cells in series before they are connected in parallel. I would do more, but the tubes are only so long.
if this makes sense: (3 cells |wire| 3cells|wire| 3 cells|wire|2 cells)

There are definitely some other quirks that need to be worked out as well:

1. Chain tensioner, it flexes and has lateral play which causes the chain to skip and pop. Fixing this is one of my first priorities. The "tensioner" doesn't really tension anything, the eccentric bolt holes on the motormount do the tensioning, and the "Tensioner" just keeps the chain from hitting the frame. I'm considering getting a much smaller rear sprocket and combining it with a 15T front sprocket in hopes of eliminating the "tensioner" and frame clearance issue all together.

2. Battery pack mounting system. The "mounting system" currently consists of a bunch of zip ties. I would like to get some aluminum sheet and epoxy it to the pack, then bend out some tabs and drill some bolt holes that I could use to mount the pack to the frame.

3. Potentiometer I'm in need of a 5k-0k pot that is not a motorcycle twist style, but rather a pull or thumb throttle. The motorcycle pot is not ideal on a trike with steering that is activated by a twisting motion...(it's downright dangerous!)

4. Rear LED lighting I want to mount two LED trailer-type marker lights in the rear for nightime visablity and safety. I plan on running them on a small, separate 16V Lithium pack made from my leftover batteries. I'll probably also invest in an HID headlamp that I can use for triking and mountain biking.

5. Braking The dual 6" Tektro mechanical disk brakes that I'm currently using do ok, but I would like to eventually upgrade to dual 8" front Avid BB7 mechanical disc brakes, for their easy adjustibility and great stopping power. I also want to figure out a solution for mounting a rear disc brake, which will probably require me making a custom mount.

6. Instrumentation I would like to soon replace the cheapo multimeter with a Drainbrain and a cyclocomputer, so I can track my Wh/mile, amperage, voltage, max speed, traveling distance, current speed, etc.

7. Tuning After the trike seems safe and stable, and I'm comfortable with the handling, speed, and braking, I would like to turn the controller up from a 100A max to a 250Amp max. This will really be a kick in the pants.

8. Highway booster pack I would like to eventually make a small, 11.1V Nominal, 25 Ah Lithium booster pack with 53 cells that could be connected in series with my original battery pack to boost the packs nominal voltage from 40.7V to 51.8V nominal, 58.8V peak. This should put me well over 50mph, especially with taller gearing.

9. Ipod plus portable speaker When there is simply nothing else to mess with, I would like to bring the Ipod onboard with a small portable speaker that I have that is powered by 6AA's. This would allow me to cruise to some tunes as I glide along on my silent trike!

Thats all I have on my head for now. I took a couple videos, but left my usb cord at school, so I'll get them up Wednesday or Thursday.

 

[deecanio]

Hi VR,

what size in mm is your rear sprocket?
you might just get away with going to a 220mm rotor (9") if you have enough clearence above the sprocket for the cliper??
i did the same thing to clear my hub motor so it may be your easiest solution for a good rear brake.
They come with a mount in kits - not sure which mount would be the best fit if your rear caliper is tetro also but worth a look, hope,hayes,formula oro and a few others do the 220mm rotors - some here........ http://www.chainreactioncycles.com/Models.aspx?ModelID=20028

cheers,

D

 

[geoff57]

hi
I have an idea for you on the chain tensioner take a look at the picture below



I am assuming the motor and wheel sprocket are inline, if the chain line is altered to follow the blue line (hidden behind the rear forks of course) and use the sprocket from the chain tensioner where the green circle is (also half hidden) that should work posable minor repositioning of the sprocket so there is room also use side flanges like on the guide sprockets of the kmx this might stop jump out.

As for the throttle I had the same problem with my KMX Mk1 I got round it by using a bar end shifter for gear changing on cycles set so it had free movment, this was coupled to a "black box" have a look at the thread I did http://endless-sphere.com/forums/viewtopic.php?f=6&t=2522&start=0&st=0&sk=t&sd=a this shows using twist grip shifters but it was developed for a bar end shifter I just know so few people use or need that type of shifter, a 5k pot is not needed though you would be suprised I could not find one so tried the 50 k and it worked on the xtlyte for ages.

geoff

 

[docnjoj]

That is one 'mean' looking machine!
Usually those recumbents look kinda 'sissy' to me, but not that one!

:: hides and waits for other Doc to see above post::

Hey! You talkin to me!?!?!?!?!?!?!?! Sissy is as sissy does!

 

[docnjoj]

Time for a front and rear suspension! Maybe dual rims and a 5" wide rear tire! Those bumps would kill my back even at 25 mph without a rear swing arm!
otherDoc

 

[AussieJester]

I wanna seez on the grass or dirt doing donuts :-|

 

[TPA]

two wheels in the back spinning and doing donuts would be far more impressive...hint...hint :wink:

 

[VRdublove]

These batteries are being a PAIN IN THE ASS. I'm considering caving in and going with some LIPOLYS from HOBBYCITY. I just want to get this DAMN THING ON THE ROAD. !

ILL put a video of it running on the road later today, IT WORKS GREAT, I JUST CAN'T KEEP THE DAMN THING BALANCED.

I KNOW IT CAN BE DONE WITH THE PVC METHOD, I'M JUST SICK OF SPENDING every waking our in the basement like a DAMN RAT.


I feel better now.

 

[pwbset]

If you want to sell some/all of your konions let me know. I'm desperate for a battery solution right now, but have very, very little money. I would also trade you a rear 26" 4011 for cells if you're looking for a backup/alternative motor. How many cells did you end up with anyway? I'm looking for around 120-160 cells ideally, but could get by on 80 or so until summer. Thanks.

 

[paultrafalgar]

VRdublove, I have considered your layout for my own tadpole conversion. What I like about it is everything is behind the seat, which means that you could put on a rear fairing (very good for aerodynamics) and the whole caboodle would be hidden: maximum stealth! It would then truely be a "Wolf in Sheeps Clothing"!
Consider it.
P.S. I didn't read the whole thread, so maybe someone has suggested this already.

 

[VRdublove]

I put a quick video together:

http://www.youtube.com/watch?v=a0UrIckWM5s


Yay

 

[AussieJester]

LOLed at you pedalling when you were next to the car floggin along hehehe...think the vid needs some more editing half of it is blank ...top effort though makes me want an etek even more now damn you lol...

 

[VRdublove]

Hahaha, I spent about 30 mins trying to figure out how to clip off the black end of the video, then I said eff it. ETEK IT!!!

 

[AussieJester]

Hahaha, I spent about 30 mins trying to figure out how to clip off the black end of the video, then I said eff it. ETEK IT!!!

I use a neat app called TMPGenc v4 you can cut and edit
amongst a host of other features, very simple to use...

 

[VRdublove]

Sweet, thanks for the tip.

I'm considering buying some LiPo packs until I get this LiMn Konion pack perfect. Here's what I'm considering:

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=7639

The Zippy LiPo packs seem to be a good deal, 22.2V, 5Ah, 15C. I would like to buy 8 of them 2S4P for 44.4V, 20Ah. Would these be fine on 250A since they are 15C x 20Ah= 300 Amp continuous? Also, how would I go about charging and balancing all 8 of the 6S1P packs at once? I have a Megapower 960SR charger/ analyzer that can handle 12S packs, would this work? I'm new to the balancing world. Do I need to charge 48S (8packs x 6S per pack), or 8S?

I appreciate any help.

 

[VRdublove]

I got a new transistor soldered into my Mastech 50V, 20amp power supply so it is working correctly again. I also recharged the 41V, 17 ah Makita Konion pack fully today, and repaired the sprung cells in two of the tubes that came apart. Every tube is now balanced again and fully charged, so I'm going to do some testing of it this week to see if it will stay balanced as it is, or if I will have to modify it some. Regardless, I'll be able to get it out for another ride tomorrow or Tuesday. Woo hoo!

I also elegantly :wink: replaced the zip ties with metal hose clamps, which are now securely holding the battery in place with minimal added weight.

VRdublove, I have considered your layout for my own tadpole conversion. What I like about it is everything is behind the seat, which means that you could put on a rear fairing (very good for aerodynamics) and the whole caboodle would be hidden: maximum stealth! It would then truely be a "Wolf in Sheeps Clothing"!
Consider it.
P.S. I didn't read the whole thread, so maybe someone has suggested this already.

I actually have considered that. I have a good friend at school here that is a fashion and materials design major, and she wants to make me a "fairing" out of waterproof material that encloses all the goodies in the rear, and has a zipper so the components can be easily accessed and vented on hot days. I'm really excited about this because I think it will really clean up the look of the trike, and make me a lot more comfortable to take it out in wet conditions.


Also, I've been trying to interpret this graph to figure out what RPM my motor needs to run at for peak efficiency, but it's not clicking for some reason. Can anyone decipher this thing?

PS. I think I'm going to request a cycle analyst for Christmas so I can see what this thing is doing. Any recommendations where I should buy?

Thats all for now

 

[PaulM]

Also, I've been trying to interpret this graph to figure out what RPM my motor needs to run at for peak efficiency, but it's not clicking for some reason. Can anyone decipher this thing?

Find the highest point on the blue "Eff" curve, which occurs around the x-axis value of 65. Draw a vertical line straight down from that point until you cross the black "RPM" curve. Go straight left from this intersection point to read the rpm value. The highest efficiency is around 86% and the rpm at this point is about 2000.

 

[VRdublove]

that can't be right... that means if I run the motor at 43 volts, and had a constant of 70 rpm/ volt, I would be turning the motor at 3000 rpms (well within its design rpms), but my efficiency would be near 0 %.... :?

 

[voicecoils]

buy the cycle analyst from the makers themselves

ebike.ca

you'll probably want the stand alone version.

Have a look at the etek graph here:

http://www.electricmotorsport.com/PARTS/EtekSpecs.htm

 

[boostjuice]

That graph looks wrong to me. All electric motor dyno plots ive ever looked at follow a basic trend.
Increasing rpm = Increasing efficiency.
Decreasing rpm = Increasing Torque/higher current/less efficiency

That blue efficiency line looks arse-about. (I think it should be mirrored left>right)

 

[paultrafalgar]

My understanding of that graph (the blue line) is that you get 80-85% efficiency between 4000 and 4300 rpm. That's what I would expect. Correct me if I'm wrong.