Etek Project: Bike to Trike

Hey guys, you may have seen my old setup floating around on here, here's a picture:


specs: http://www.evalbum.com/1618

and the youtube video:
http://www.youtube.com/watch?v=h5vgWVdU-XQ

I decided to start building a new Lithium battery pack similar to Doctorbass's Makita lithium pack to shed some weight from the bike, and extend the range. I decided on building a 40.7V nominal, 29ah. (11s10p).

After starting to build the pack, I started to consider a new, sleeker, more stable platform.
I decided on a tadpole trike for a few reasons:
1. Stronger steel frame
2. Better braking (2 front disc brakes)
3. More aerodynamic
4. More comfortable
5. Ability to seal off electrical components
6. Low center of gravity.

KMX trikes seemed to be the most suitable for me, with strong steel frames and a sub $1k pricetag. So I settled on the KMX Typhoon, which I am buying a 20"front and 24" rear wheelset for.



It's supposed to show up tomorrow. As for the location of the components, I'm planning on mounting the motor on an aluminum bracket beneath the seat, right in front of the rear tire. The battery boxes will be saddled, 18 volts on one side of the trike, 22 volts on the other side, beneath the seat and along the frame rails towards the middle/front of the trike. The controller will hopefully mount on a flat surface on the back of the seat. I'll find spare room for the contactor and keyed ignition when I look the trike over.

Here are some pictures of the power supplies and the lithium batts that are getting individually charged and analyzed:




As for final specs, I'm hoping the entire trike is sub 105 lbs. The controller will be programmed to 250 amps peak, which, at 41 volts is just over 15 hp. I'm looking for a top speed of 50 mph, and range of 30 miles at 30mph on flat ground.

I'll get more pics up as I receive the trike tomorrow, and of the lithium pack as it progresses.

Badass! I'm thinking KMX also for winter riding... seems the only logical choice to continue ebiking safely in the snow/ice (knoxies snow KMX video sealed the deal for me there). Thanks for sharing your DocBassBattJrâ„¢ build... I'm doing one also at 20s6p... little guy compared to you all. :wink:

Please let us know how you plan on connecting the cells. I've been looking at braid, battery bars, solid 12awg, stranded 10awg etc. etc. and just can't decide which would be best. I don't have near the tools or skills of Doctorbass so need to figure something out that a lame brainer like me can solder together.

EDIT: You should specify 11s20p for your batt... unless people have worked on konions where the pair is treated as and thought of as a single cell they wouldn't understand that. :wink:

Anyone tried liquid solder for connections n the batteries? Available from Dick Smith here in OZ...

Look forward to the build mate best of luck

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

RLT said:

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

Click to expand...

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

Hehe, great project, it was waiting to be done!
Cedric Lynch saw my electric KMX at an EV rally this year, and was dead keen for me to put one of motors in it. Truth is, it scares me even with 3kw of power, but then, i'm getting old :?
Good luck, looking forward to seeing how you get on.

Nice!!!!!

this should fly like shit of a stick!!!!!
keep us posted with some more photos during the build, sheeesh thats a shed load of batteries!!!
with all the stuff on here it's only a matter of time before we need a car section , no bad thing i reckon
Jozzer, get the hell to bed bro it's 4 am!!!!!


Cheers,

D

Thanks for all the positive responses fellas! To connect the batteries, I'm planning on using .1mm Nickel sheeting and the $200 battery tab welder: http://www.ledhacks.com/power/tab_welder%20ii.htm to connect the individual cells. I'm off to bed for now, don't feel like doing much since I'm sick as a dog.

AussieJester said:

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

Click to expand...

Sorry, but they usually DO look that way to me. I can't help it;
I realize that they are much more efficient and faster, and anyone that rides one, especially on the city streets, is braver than I .....
nonetheless....
--------------------------------------------------------------------------------------------------------------------------------------------------

Thanks for all the positive responses fellas! To connect the batteries, I'm planning on using .1mm Nickel sheeting and the $200 battery tab welder: to connect the individual cells. I'm off to bed for now, don't feel like doing much since I'm sick as a dog.

Click to expand...

.1mm is pretty thin. Especially for something that can draw current like an Etek. That's only .004 inch. While you might find it entirely satisfactory, I think I'd be remiss if I didn't recommend that you use something thicker if you can. The .003 inch stuff I tried in my earliest experiments just didn't seem safe for anything that pulled more current than, say, a laptop computer battery.

The .005 inch that I used on my first packs, I consider to be too thin for even 2KW draws. I switched to .01inch (.25mm) for my newer packs and feel a little better about them, although, if I could find some at a reasonable price, I think .007 inch (.18mm) would be ideal for bicycle and scooter battery packs. It should give the perfect balance of easy weldability, Current carrying and mechanical strength.

Or maybe at least double up on the .1mm stuff at the critical points.
IMHO /YMMV

Hope you feel better soon.

Hi

Looking forward to seeing this one!! and I will second what Jozzer says about the speed, mine scares me at 30mph and starts to feel very twitchy and unstable over that esp when you peddle as well, at speeds above 30mph I tend to hang on for grim death :lol: they are a lot of fun though and you always have the option of turning the power down and getting more range, they are scary in traffic but fix the flag to it and get a good helmet and a jacket with elbow protection, this will be a lot easier to roll, the new KMX will be a lot more stable at higher speeds as it has bigger wheels.

Good luck with it all will be keeping a keen eye on this one! hope u are feeling better soon.

Knoxie

Thanks for the insight on the nickel sheeting thickness RLT. I was kind of unsure on what thickness is appropriate for 250 amps max current. Where have you been purchasing yours?

Holy crap! that thing is going to be able to destroy a back tire in no time.

Are you going to keep the pedals functional?

I seem to remember Knoxie mentioning something about some frame weaknesses. With an Etek, you might want to reinforce a few spots.

Wow, that is going to be a real beast, for sure. Maybe you should consider one of those super-wide tires in back, like dirtdad used on his Stiletto conversion. A lithium-powered Etek would smoke that one as well.

-- Gary

Nice power supply! I got the same one off ebay a few months ago. It's great.

Electric tadpole trikes are a nice platform to work with, I think you'll be very pleased

VRdublove said:

Thanks for the insight on the nickel sheeting thickness RLT. I was kind of unsure on what thickness is appropriate for 250 amps max current. Where have you been purchasing yours?

Click to expand...

You can get .01 or .005 from Admiral Steel:
http://www.admiralsteel.com/shop/201.html

Even though they seem to have raised the prices since my last order, they are still, by far the most reasonable price I have found.

Oh, and if you ARE going to use .01 with the "$200 CD welder" you will most likely need to use a power supply capable of 17-18V (or higher if the capacitor will actually handle 20V) . 12-15V just won't make solid welds with the Car audio caps I have tried.

(I wish I still had my rolling mill; I'd roll some .01 down to .007... I found some .007 available, somewhere, back when I was searching diligently, but it cost 'a fortune and a half' for a small strip.)

Thanks for the link RLT. I finally received the trike on Friday, along with the capacitor and footswitch I needed for the tab welder.

I went out for a ride and the thing is an absolute blast (no motor). I rolled it already, so I have a better feel for my limits. I was joking around in my driveway, trying to make some sharp, hard turns, and it just threw me off when I popped one a little too hard. Later in the ride, I thought I was going to wreck, but the trike surprised me. I was riding in the rain and was in top gear cranking it out when a speedbump popped out of nowhere, giving me no time to react, but the trike went over it much more calmly than I did. I thought I was done for, but we bounced over it, and I was good to go. This is a very strong frame! The typhoon has a high carbon steel frame, while the next model up, the Cobra, has a chromoly frame. I'm probably going to ride it around town this week and whatnot before I really start tearing into the fabrication. The first step is getting a good Etek mounting bracket fabbed up out of some aluminum. Then I need to figure out exactly where I'm going to put the controller.

Here are some pics:


all put together, ready to ride, with the mockup battery pack



Rough placement of the etek and one of the saddle battery packs (not the real pack).


Finished battery tab welder, with an elegant woodgrain finish!


I managed to already blow my 130A SCR on the tab welder, so I'm in the market for a larger one. Anyone know where I can find one? The larger ones seem to be scarce on ebay.

I'm also going to attempt to order the larger wheelset tomorrow. I think that will really help with the twitchyness at higher speeds. (Going from 16"/20" to 20"/24")

That's it for now

Excellent, looking good. Lucky the new trike has a hard seat, my old ones would leave you with a motor digging in your back!

The frame on mine split underneath at the join, I hope they have fixed that weakpoint. It's an easy repair with a welder to make it all solid if you want to be extrasafe.

One thing worries me, I have found that anything below frame level WILL sooner hit something. Dropping off kerbs, minor rough ground, tufts of grass or plants, they all give that part of the frame a whack from time to time. I'd suggest if you really want the batts below that hieght, then weld up a solid battery plate to protect from underneath. It gets pretty wet under there when it rains too, but I don't suppose thats a problem where you live
It might help get you more traction if you mount the batts pannier style around the rear wheel, you've probably noticed already they are very light at theback end, and you can wheelspin them even with the pedals if you lean forwards just a little!

Steve

knoxie said:

Hi

Looking forward to seeing this one!! and I will second what Jozzer says about the speed, mine scares me at 30mph and starts to feel very twitchy and unstable over that esp when you peddle as well, at speeds above 30mph I tend to hang on for grim death :lol: they are a lot of fun though and you always have the option of turning the power down and getting more range, they are scary in traffic but fix the flag to it and get a good helmet and a jacket with elbow protection, this will be a lot easier to roll, the new KMX will be a lot more stable at higher speeds as it has bigger wheels.

Good luck with it all will be keeping a keen eye on this one! hope u are feeling better soon.

Knoxie

Click to expand...

hi
ill be keeping an eye on it as well nice to see someone else doing an external motor build on a kmx, my first was like that but the motor was not any ware near as powerful. the guys are right the frame is a bit on the weak side but that was on my first one I am now on a kmx mk2 model viper I moved to a puma for this build. This new design of frame is a lot stronger so we should have no problem with frame twist which was the problem. I will tell you now though that seat is not ideal keep an eye on my thread Mk 2 KMX the Viper second eKMX http://endless-sphere.com/forums/viewtopic.php?f=6&t=4189&st=0&sk=t&sd=a I am going to design a seat better suited for etriking at speed in comfort once the trike works.
knoxie this is the typhoon it has 16" front and 20" wheels and is close to the ground so has a low centre of gravity,to get that the ground clearence is 3" 8cm jozzer is right the battery pack needs protection that close to the ground. it will be a fast one when finished.

Well I'm finally getting into it again after a week of some of the worst poison ivy of my life, combined with the dang flu! I've had it bad before, but never in my eyes! Here's a picture of it right before I got a shot of prednisone in my butt:


Anyway, I had plenty of time to think during the last week, and I decided against spotwelding this large battery pack together for a few reasons:
1. The vibrations that this trike will see could be extreme, and spotwelds make me nervous.
2. Spotwelds make the pack pretty permanent, and I like the idea of being able to remove cells as they go bad and replace older cells with newer ones as they reach the end of their life cycle.
3. I don't know if my homebrew spotwelder is capable of welding the thickness of nickel sheet necessary to carry 250amps of peak current.
4. I can see myself screwing up halfway through my 200 cell pack that I was planning to weld.

So, I started to consider the idea of making the pack modular, so I could add and remove capacity as it is needed for the trip, and I could swap out cells if I ever wanted to. This left me with the solderless power tube idea, but I wasn't spending that much money on a kit, if I could even find one. As per safe's recommendations, I found out that 3/4" Schedule 80 PVC pipe was the perfect size to hold a stack of Sony Konion cells. I'm using a 1/2" by 1/8" copper bar to connect the eighteen individual 41volt/1.5ah tubes in series, for a total of 41V/27ah. This copper bar will also provide the framework for the pack, so bracing isn't necessary. Each tube holds 11 Sony konion cells with a spring in the middle to keep constant tension. Nickel tabs will be spotwelded onto the positive electrode of 6th and the negative electrode of the 7th cell, and they will be soldered together by a slacked (10 AWG?) wire. This will allow the spring to expand and contract while the connection remains.

Here is my initial drawing of the pack:



And here is what it is looking like so far:


(steel is being used for mockup)

My only real problem so far is trying to figure out what size wire will be needed inside the spring to handle an entire pack current of 250 amps peak. My electrical engineering skills are a little weak, but I'm assuming that this wire would see 250 Amps / 18 tubes = 13.9 Amps peak. Is that correct? If so, I think 10 AWG would work fine. Opinions?


Other news: I received the larger 20" wheels for the front, and am waiting on the tires. I also got the Sevcon Millipak programmer so I can modify the settings on the controller. That's it for now, I'll post up as I make more progress on the pack.

That's wicked cool (uhm... except the poison ivy part). I keep reading about how you should parallel first and then series. What's your take on that? I might seriously consider your PVC method if it looks like you're having good success with it. I only need a measly 40a max draw for my 20s6p konion pack. Heh, heh!

DAMN I saw the pic and immediately thought this dude has been smoking some premo bud how do i get some!!!11 hehehe... You can imagine my disappointment when i read it was poison ivy and a cold Anyhooot LOVE the battery packs i like the spring in the middle setup very clever...

Ditch the spring and put a threaded adapter on the end with a plug. Then just tighten the plug to squeeze the cells together.

Also, its better to parallel first, then series. (keeps more cells in ballance.)

Ted_Z said:

Ditch the spring and put a threaded adapter on the end with a plug. Then just tighten the plug to squeeze the cells together.

Click to expand...

Hi,

Might be a problem when the cells expand and contract due to temperature.

Made some great progress in the last month. What a project! I worked about 8 hours a day for a full week to get this thing done. The only real issue I'm having is getting all the battery tubes to discharge. All of the cells stay balanced in their individual tubes, but it seems that only 6 of the 12 tubes want to run the trike at a time.

Anyhow, here's some pics, Ill get a video up early this week.









I blew one of my power supplies by running it at a slightly higher voltage than its max rated voltage, does anyone know what might have blown on it?

That's all for now!

WOW
thats one monster KMX.
nice work Tommy - man that thing must fly?????


Cheers,

D