DiamondBack, Cyclone 650watts and Dewalt A123 packs

[EVnewbie]

Kfong,
Love the build with the Dewalt battery packs! I would love to get those connection boards from you complete with isolatation shottky diodes I assume. If you have a spare three position battery holder laying around, I'll buy one from you! My basic build is a 32V 14 amp controller running Dewalt packs with the wimpy motor running through a 7-speed rear hub. If I do this right, I should be able to squeeze 3 batteries into the front triangle so am very interested in your mounts. My wife wants for me to make an electrically assisted bike that looks "normal" and your triple connector board would make the battery pack look neat.

Big thumbs up on the build, it looks great!

 

[kfong]

I should have plenty of boards for the dewalts by next week. These boards isolate the separate packs as well as go through the normal fet ouput of the bms in the dewalt, that means they will automatically shut down if the voltages go too low, using dewalts built in safety setup. Even though I've been testing the bike on 2 dewalt packs, I don't recommend people doing this, since the packs are not designed for high current. You should be running a minimum of 3 packs in parallel to keep the current load low. I will eventually have 6 in parallel and that will keep my packs happy.

I don't have any spare battery carriers, but I've seen people make them out of wood or aluminum bar stock. The material I used was polycarbonate, or lexan. Very tough stuff but kinda expensive, I don't know of a cheap source for such material. A wood carrier with aluminum rails would be an easy way to make them.

 

[kfong]

Woohoo! finally have the boards to finish the dewalt pack.

Here are pictures of the boards on the bench. They work using the internal dewalt BMS. My load is only a 100watt resistor, drawing a little over 3amps. Even this gets hot, so I have a small fan to help cool it. The power analyzer that I'm using can chart the battery drain. At around 27-28 volts the bms cuts off the batteries, so the interface boards are working with the internal bms as expected. Now I need to test it on the bike itself. The bms will shut down if it sees a large spike from the motor. This safety feature isn't desired on an ebike. A 300uh power inductor and a diode across the motor will be needed on some setups to prevent this, but I've tested this on even cheap brushed systems and don't find a need for it. I didn't find it necessary on the cyclone setup as well. Here are charts of the bms working and the board and test setup. Now I can just use the Dewalt pack without having to open them up, and maintain the 3year warranty. As long as you don't push more than 20amps per pack you should have no problems using the dewalt packs as a bike battery. I recommend having at least 3 packs in parallel so the current load is spread out. This will give you 60amps to draw upon. The more you parallel the easier it is on the packs. My setup will have 6 packs for a total of 120amps. As long as you don't exceed the designed current draw, it will last as long as any battery used on dewalt power tools. Dewalt has a good warranty replacement program, and I have been using the packs on my ebike since last year. I have 4 dewalt chargers and find it very convenient to have a full charge in less than an hour.

 

[kfong]

Some more progress, I was not able to find the proper connectors for the power connections. I ended up picking ones found on Digikey for the source. They do need to be modifed, you can see how I had to file the connectors down so they will work with the interface board.

More pics of the interface boards

Here is how the interface board will be cradled by the carrier. I plan to use plumbers epoxy to secure them into the holder.

 

[liveforphysics]

Very Cool!

Great work! I love the custom LVC boards!

 

[kfong]

Thanks, I started a new post on the boards so all technical questions and partslist will be posted there.
http://endless-sphere.com/forums/viewtopic.php?f=14&t=10986

 

[kfong]

I had a setback, when I started this project. I used a old bike rack that was sitting around. Not really noticing the quality or strength of the rack since it was rather new. Well one of the welds broke the other day and after taking it apart. I found I could literally bend the rack with hand pressure. The aluminum rods used is just too thin to be a sturdy rack to hold the weight of the batteries. I’m kind of stuck with the setup since I made the battery mounts custom to this rack, so now I’m in the process of getting the rack more solid with bracing. I still might look into a new rack, if I can modify my setup to fit.

 

[kfong]

I’ve decided to upgrade the bike rack to a steel one instead of trying to fix the old one. I now need to redo the mounting hardware for the batteries. In the mean time I'm back with running 2 dewalt packs till I get it all sorted out. As you can see from the pictures the weld gave way due to all the riding I’ve been doing. The second one shows the bend in the main spar, this is after I tried straightening it. The aluminum rods are just too thin to handle the loads. I’m pretty hard on my equipment. I’ve already bent the rear rim by going over a curb too fast when I knew I should of slowed down. My next purchase is big fat road tires to take up the impacts I keep giving the bike. This will also give me a much smoother ride as well. I will also be bracing the steel rack as much as I can. I also like how the new rack has the main spare directly above the wheel axial, this one should handle the loads better.

 

[kfong]

I’m currently still riding with 2 packs, but have to be careful not to draw more than 40amps, especially on starts. This is fine till I get the battery trays worked out for the new bike rack. In the mean time I picked up a set of plastic fenders. This should extend the ability to ride even after a rain storm. They work great, tested them right after a recent storm, clothes remained clean and dry even after going over some puddles at high speeds. I’m getting an average of 9 miles with pedaling on 2 dewalt packs. This covers most of the distances I need for errands. I hope to have the other 4 packs online soon, then I can finally shorten the wiring and clean up the overall look.

 

[kfong]

Not much in updates. I’ve been having too much fun riding the bike. Since I still haven't electrified my Motobecane mountain bike. I decided to try the Diamond Back on the trails before I get the battery tray installed. I'm only able to run 2 packs strapped to the bike rack, but it's secure enough for trail riding. I wasn’t sure how 2 packs would perform on the hills, but I’m happy to say it’s adequate. I had to slowly ease into the throttle and kept the throttle usually just enough while in low gear. I only had a few cutouts at first, but did not have those issues on my other packs, once I learned how to current manage the motor. I didn’t have any problems with the left cranks being extended; I was usually in second from low or middle gear through out the ride. The trails are single track and technical so you don’t really get to go too fast. The only complaint was the motor being at the bottom. This isn’t good since logs and downed trees would hit the motor. I would have to lift the bike around it. I would get around 6 miles through the trails with pedaling on 2 packs. I spent the afternoon riding out 6 packs. I was having a blast with the bike and didn't want it to end. Only drawback was I would have to ride back and switch packs. Too bad I didn't have a charger setup so I could keep going, but I was out there for quite a while. The bike held together quite well. I was expecting motor mounting problems or controller issues. Only had a loose steering arm that was corrected before my next two packs. It’s a fun setup for the trails; too bad the motor is mounted on the bottom. Happy to say the dewalt interface boards never once came loose or gave me any problems. It's a very good friction fit. They are only plugged in.

 

[kfong]

Here is my current setup. I've been using the bike on the trails more than I thought I would. Even though it's a solid frame, it's been reliable and I've been having way too much fun. I had to compromise between weight and battery capacity. With 3 packs I don’t have issues with the packs wanting to shut down on the steep hills. 32V * 60amps = 1920 watts of power. I’m usually on the second lowest gear or if it’s a big hill I switch to the lowest gear. I pedal as much as I can to keep the range at around 10miles. I did 12miles the other day on 3 packs. It was an 88degree day and I wasn’t sweating much. It’s a fun workout. As a comparison, on flat roads without pedaling I would get 8-9 miles. I will be staying with this setup until I get my Motobecane converted. The 3 batteries are light enough in the back that I don't notice them. The new steel rack is holding up quite well. The battery interface is also holding up well in the trails. I'm even thinking about remounting the motor in the triangle of the frame to get the motor up higher, but that will probably be a winter project. I probably should clean up the wiring, but plan to replace the wattmeter since I don't like the long power lines.

 

[jk1]

Kfong what resistor values are you using to drive the dewalt PWM circuit ?

Are you running it at 100% duty cycle i.e 34 volts ? or less than that ? what is the maximum amps you can get out of it before the internal over current protection trips the pack out ? 15 20 or 30 amps per pack ?

i was running mine at about 28 volts so approx 75% duty cysle and if i draw anything more than 15 amps per pack then the BMS Cuts out, then i need to unplug and plug each pack again.

I have a feeling the higher the Duty cycle the higher the current limit is.

 

[kfong]

I have no problem drawing 20amps, anything more and the BMS takes over, temporarily shutting down the pack. If you continue then it will fully shut down. You can feel the motor shuttering when it hits the trip point. I just let off to prevent total shutdown. With 3 packs I rarely run into this problem. The only time I do is when I’m in high gear and accelerating to fast drawing way more than 60amps (20ampsx3packs). More technical detail is posted here http://endless-sphere.com/forums/viewtopic.php?f=14&t=10986

When I’m riding in the trails, I don’t have any issues, since I’m usually in low gear and I’m pedaling as much as I can to assist. In the lowest gear, I can pretty much can just ride it up without helping the motor out. I’m finding the cyclone to be fairly efficient if you are in the right gear ratio. On flat city riding without much pedaling, I get about 3miles per pack.

 

[jk1]

where did you come up with your resistor values for the BMS ?

on mine i have adjusted them so i dent get full volatge, i am running somehting like 75% duty cycle which is like 29 volts under load when fully charged. I can tweak the resistor values so i can get 100% duty cycle and hence 34 v. The question i am windering is what is the BMS amp limit at 100% duty cycle ? At 75% duty cycke i am pretty sure its 15 amps. At a lower voltage of 19v its less than 10 amps . So i am guessing with the correct resistor network and full volatage we may get a lot more than 15 amps.

I was reading on some forums that people were drawing over 30 amps. Some dewalt power tools have a built in blade fuse that is 40 amps, so it would not suprise me that we can oull 30 amps per pack.

In this article here in figure 1 they talk about altering the resistor network, what i new is that altering the values will alter the duty cycle, but what is intersing is that you can also alter the Voltage of the divider and hence the frequncy.. i think it may have something to do with this change that may allow fulll AMPS out of the BMS.

http://electronicdesign.com/Articles/ArticleID/19322/19322.html

 

[kfong]

I took the value from a hammer drill, I tore apart. Those require full power, since stall torques can be very high. I'm running them at 100% duty, since I'm getting full voltage out of them. 20amps seems to be the limit, if you see the wires going to the BMS. You will see why. The design was never meant for high current, even though the batteries are capable of it. It's simply not needed in power tools. Long running time is what they designed it for. You just need to parallel them for the currents you need. With an efficient bike setup, I'm getting 3 miles per pack. The fuse portion is only 15amps. So I really don't think 30amps is a possibility. Power tools might have a fuse of 40, the bms doesn't always trigger right away, short burst can go that high before the bms reacts, can't be blowing out the fuse everytime.

 

[kfong]

Can’t believe I’m doing this. I decided to upgrade the bike. Originally, I picked up an RST Gila front shock only to be disappointed at the install. The 1” steer tube was too long. I wasn’t too happy with the shock as well. When I saw Oatnet selling frames for $75, and 2 for $100. I couldn’t pass up the deal. This will bring my ebike up to date and allow me to use a better front fork as well. I will be redesigning the motor mount to a higher location. I’m finding the Cyclone setup to work fairly well out on the trails. The frames should arrive soon.

Update on the Motobecane. The bike that started this thread and my journey into ebike land. I’ve been taking my time about this setup, since I really like the bike and didn’t want to change it or the gears. The only option seemed to be a brushless hub motor that was geared so I could use it on the trails. I was tempted to go the RC route, but decided to test that on a spare bike. Can’t be messing with an untried setup on a good bike. When I heard about the BMC 1000watt motor. I waited for it. The long wait had me looking at other options. Since my trail riding, I’m more aware of the power I need. Since I like to pedal for the workout, 600 watts is plenty. I originally wanted the 1000watt motor, thinking that it would be more durable. I have since learned that they both use the same green composite gears. From field reports, the 1000watt motor is also current hungry. I don’t find that too good, since I want long trail rides. They are also having a hard time with controllers, Kelly’s seem to be the current choice but that’s a rather big controller, and I want everything as light as possible. I hate pedaling the current cyclone setup in the trails, but love it when I have battery power. So the ideal setup is to make an e trail bike as light as possible, so if I'm deep in the woods, I can still keep going even if the batteries are dead.

I ended up ordering a 600watt bmc torque motor from Ilia, his pricing is very good and he has been very responsive on email and delivery. My motor will be shipped out next week once the tire build is done. I wanted all in black. Should be another fun ebike project. I now need to get my butt in gear and build up the battery packs. They are Konions from Doctorbass. I was hoping to build a spot welder, but I will just solder them now. I will have to create a new thread for this build.

 

[oatnet]

When I saw Oatnet selling frames for $75, and 2 for $100. I couldn’t pass up the deal.

Enjoy your frames Kin, it looks like you will have them tomorrow, and I can't wait to see what you do with them!

I ended up ordering a 600watt bmc torque motor from Ilia .... I wanted all in black.

Funny, me too! I am currently waiting for delivery of my 1000w V3 from Ilia, and also asked for all black, in a nice fat Alex DX32 rim, gonna put it on a black frame and build a blackout bike with it. I ordered it a few weeks ago, but delayed shipping to get the black rim, and later for black spokes.

-JD

 

[kfong]

Nice, can't wait to see what you do with the 1000w bmc. Did you settle on a controller, what voltages are you planning to run. The 1000w motor is very similar to the 600w torque until you up the voltages. This is from what I've read on earlier posts and what I was starting to suspect. I'm not familiar with blackout bikes. Is there a link to the bike on the web?

 

[oatnet]

Nice, can't wait to see what you do with the 1000w bmc. Did you settle on a controller, what voltages are you planning to run. The 1000w motor is very similar to the 600w torque until you up the voltages. This is from what I've read on earlier posts and what I was starting to suspect. I'm not familiar with blackout bikes. Is there a link to the bike on the web?

I'm going to start at 72v, and I want to test a few controllers I have laying about with it, first a 72v20a analog xlyte, then a 72v50a "knuckles" infineon, then a 72v100a Kelly. Depending on whether the Kelly can handle the RPM, I might buy the 120v Kelly for some sick speed testing, and I might migrate it to a full suspension frame at that point.

By 'blackout' I just mean all black. . I have a black Tidalforce IO Cruiser frame (HT), and I just picked up an old Rock Shox Boxxer in black, and a 20mm through-axle hub that I'm going to mount on black DX32 rim with black spokes, just like the V3. The only thing not gloss black will be the rim brake surfaces, the fork stanchion tubes, and the 203mm disk rotors (unless I find them in black too)

-JD

 

[kfong]

Woohoo, got my frames from Oatnet. Have to say they are very well made and solid. The frames are aluminum and fairly light. The quality is excellent. Here are pics. They were well packaged. Ended up ordering 2 but needed only one. Now to decide on which color to go with. Waiting on my front fork, picked up a rockshock tora SL, waiting on that before I progress further. I plan to move the components from my old bikes for now and later upgrade to disk brakes, ect, when the need arises. Really looking forward to riding the bike with a front suspension, my wrists were taking a beating after a 1000 ebike miles. Very happy with the frame geometry, it compares to my Motobecane. Should have a similar feel.

 

[oatnet]

I'm glad you are pleased with your frames!

I resolved my wrist problems by switching to Ergon Grips a ways back. The big pads that your palms rest on keeps your wrists at the proper angle and help distribute the weight. I had to figure out how to adjust them though, so the pad keeps your hand in a normal position. The GC2 is about $30-$35, they have a whole range of lightweight/more expensive ones too, and some cheaper ones without the palm pads that I think miss the point.

-JD

 

[kfong]

Thanks JD, I will look for those.

I finally got my BMC motor. It's the 600 watt torque version. The phase wires look too thin, so I plan to beef them up, once I check everything out. I'm disappointed with the wheel build. It was not dished properly. Actually it was not dished at all! This is a common thing that bike shops do for rear tires. I picked up the wheel from Ilia; He needs to get a better wheel builder. Looks like I will have to find a place local to redo it. I was hoping I didn’t have to deal with this part of the build. Has anyone done there own dishing, how difficult is it? Here are pictures of the wheel mounted on the bike. You can see the wheel is not centered and is off to the left a noticeable amount. This is really unacceptable, the spokes also seem like they are not tensioned enough. My original wheel has a higher pitch.

Here are picture of the cycle analyst, the 35amp/72 volt crystalyte controller and my CNC battery tray. I will anodize it black once the parts are finalized. I’m going to start a new thread on the BMC motor since the current cyclone build is evolving into the Tidal Force, so I will keep this thread for that build.

Thread for the BMC build
http://www.endless-sphere.com/forums/viewtopic.php?f=6&t=12654

 

[alswiseowl]

Hi kfong,
just a couple of q's,when you where running the 650watt cyclone at 36v how did it go,
good enought for torque and hills or would 48v be better,thanks
its just that im stuck in between choosing the 36v900watt kit or the 48v1200watt kit..
either way i also would be interested in these dewalt pack set you have made easy to rig up,
thanks

 

[kfong]

I'm happy with the setup since I really don't need to go fast on a bike. With it on second from granny gear I get from 18-19mph and good efficiency. With this on 3 packs I get from 8-9 miles with little or no pedaling. If I want to go faster I can put it in higher gear and get it easily to 25mph, but loose efficiency. Since the bike is only rim brakes, stopping distance is rather bad, so I’m content to go slower. Since I ride on the sidewalks a lot, going fast is not really a good idea. The motor stays at a comfortable heat range and seems to be lasting at this voltage. I think the 900 watt kit is the same motor, just higher voltage. Might even be the same controller, hard to say for sure. I'm using the setup for the trails, usually riding in the granny gear and it has no problem going up steep hills. I usually pedal too to get up faster. Hard to go fast through single track without getting hurt, quite happy with it on the trails. Motor seems fine even on a 90deg day.

Hi kfong,
just a couple of q's,when you where running the 650watt cyclone at 36v how did it go,
good enought for torque and hills or would 48v be better,thanks
its just that im stuck in between choosing the 36v900watt kit or the 48v1200watt kit..
either way i also would be interested in these dewalt pack set you have made easy to rig up,
thanks

 

[kfong]

It was hard for me to tear down the Diamond back; it’s been such a great work horse and fun as well on the trails. I think I will hold off till winter to get the Tidal Force completed. Who knows, I might end up with yet another ebike. I’ve been thinking a dual hub setup would be very cool to have on the trails. Both wheels would provide quite a bit of traction. I had dismissed hub motors for trail use but with two motors I think traction for hill climbing could be possible and still be a fairly light setup. I know a 5000 series crystalite hub motor with lots of voltage would do it, but pedaling such a beast in the trails is not something I ever want to do. Here is the latest picture of the Diamond back, I did a quick stop at the grocery this morning. Hard to be without an ebike, been using it for local errands a lot and I still bash it on the trails. Freewheel needs to be changed out, been holding up so far.

The latest addition is fake leather upholstery material for the battery cover. I picked it up at the local fabric store. I used velcro to put it all together. Quick and easy to make. It looks like it's part of the bike. This is for leaving it outside stores, ect. I also leave the bike looking trashed so it gets little attention.