Build No. 2 - Reduction Drive - now w/ NEW video

[mauimart]

IT"S ALIVE!
I scrapped the 5:1 pocket bike transmission and put the planetary reduction on hold and this is what I came up with.
Standard dual reduction using 5/8" jack shaft.
From motor to jack shaft: 9T:54T, no. 35 chain.
From jack shaft to freewheeling bottom bracket: 14T:48T (Overall reduction from motor to crank: 20.6:1)
From crank to wheel: 24T:32T (1st gear), 24T:11T (8th gear). Overall reduction from motor to wheel: 27.4:1 (1st gear) and 9.4:1 (8th gear).
The motor is a rewound turnigy 80-100, 9-turns, 14AWG, wye, internal halls at 120 deg.
Controller is a Kelly KEB72800.

Initial test rides have been very encouraging and fun. I love the full suspension coming from my first build which has none. I also like the ability to be able to pedal the bike. I am currently running a 18s1p 5Ah pack of Lipo's. Full-up weight is 57 lbs. Controller is set to 50% rated current. This thing has got some giddyup.
The plan is to do some more testing to make sure the mechanical drive train will survive what the motor will dish out and to see if the motor can handle my commute (7 miles, 1800 ft elevation gain) without overheating or blowing up. Once satisfied with the performance I will begin cleaning-up the build - using nuts an bolts instead of zip-ties, trimming aluminum, some lightening holes in the 54T sprocket, finding a permanent location for the controller, and adding a bigger batter pack (hopefully ~1kWh in the triangle). I'll try to get some video...
Martin

[adrian_sm]

Very nice. Great to see you get a dual suspension/RC build up and running. Oh, and I like the digital dash.

Be careful with the clearence to the front wheel, wouldn't want the motor mount bracket to hit the wheel at speed.

What speeds can you actually pedal assist to. Looks like a pretty small chainring.

- Adrian

[mauimart]

Very nice. Great to see you get a dual suspension/RC build up and running. Oh, and I like the digital dash.

Be careful with the clearence to the front wheel, wouldn't want the motor mount bracket to hit the wheel at speed.

What speeds can you actually pedal assist to. Looks like a pretty small chainring.

- Adrian

Thanks Adrain.
The picture is a bit deceiving -- the clearance is ok. I have fully compressed the front shock and there is no interference. I will eventually trim/round that front corner of the bracket to give me even more clearance.

The chainring is indeed small (24T) but in the highest gear I can pedal up to around 16 mph which for 5-7% grades is more than enough. I reckon I will pedal only if there is a problem with the electric drive. I save all of my pedaling energy for my road bike.
Martin

[spinningmagnets]

Too bad there is currently no affordable outrunner motor selection halfway between the 63mm motors and the 80mm. I doubt you will ever have to worry about the motor heat. Looks good, best of luck!

With 18S LiPo and giving the motor some gears, I am certain you will be happy with its climbing ability.

[Kurt]

The bike looks great. I am keen to see what data you can collect. top speed, amps, temps and so on . A video or two would be great .

Too bad there is currently no affordable outrunner motor selection halfway between the 63mm motors and the 80mm

The 80mm motors are not that big or heavy really when you think about it. Not having everything running on the limit is a good thing in my book.

Interesting how all the medium and large turnigy out runners from HK have been on back order for a very long time. Will be interesting to see if HK come up with some new low KV large RC motors to meet the demand for them.

The great thing about using a cheap RC motor is its such a simple job to change motors compared to a hub motor having to rebuild a wheel every time

Kurt

[spinningmagnets]

Not having everything running on the limit is a good thing in my book

I couldn't agree more. I just bought a house in Kansas, so I am fresh out of time and money, but if I suddenly found myself with a lot of both, I'd say the 80-85 is the hot ticket for this application. Even with a complete reworking of the motor immediately upon arrival, The shaft/shell/baseplate/and magnets are worth the HK price.

Disassemble, add the proper epoxy between the magnets to lock them in shoulder-to-shoulder, swap the bearings to the mid-grade NSK for a big improvement thats still very affordable, rewind the copper per Thud to a the lowest practical kV, and terminate the windings in Wye to ease the current and heat @ the controller (of course add a cheap temp sensor to the windings). A low amp-draw system also means you can get high performance from a non-LiPo chemistry (C-rate limited).

Add Berties optical sensors and a Lyen 6-FET run at 44V-48V, and the motor/controller would never be the weak link in this configuration. You would need some way to prevent power from being applied when at a stop in a high gear, or things would break.

I would even look for some way to snub the throttle to prevent shock-loads due to a sudden application of full-throttle. Between Justins RC-CA, Keplers interface, and Adrians brain box, I'm not sure yet which would best provide that with a system such as I've described. I just checked the Cyclone-USA website and the closest kit to this would be the 48V 1200W single-cog kit for $969 (+ T&S), and thats even with the need to immediately upgrade some of the components...

[mauimart]

video finally...

[knoxie]

very nice looks and sounds like a good setup there, be interested to see it all tidied up and how it fares on longer rides, you figuring to up the battery capacity then?

[AussieJester]

That is one of the best edited e-bike videos I have seen what program do you use? Nice job on the setup will look slick when finished !

KiM

[mauimart]

Thanks for the compliments.

very nice looks and sounds like a good setup there, be interested to see it all tidied up and how it fares on longer rides, you figuring to up the battery capacity then?

The plan is to clean it up and add 10 to 20 Ahr, 18s pack. I have tried a number of times to tear it down for rework but I can't seem to bring myself to doing so as I am having too much fun riding this thing. I like to call it extra qualification and validation testing... I plan to get the controller out of the triangle and reserve that space just for batteries. I'm really enjoying the off-road experience this bike has to offer and in the process I'm noticing how crappy the suspension is. It has me wondering whether I should invest in something a bit more modern and capable? In any event, lots to do to make it better - after I ride it a few more times.

That is one of the best edited e-bike videos I have seen what program do you use? Nice job on the setup will look slick when finished !

KiM

I used iMovie '09 to edit the video. It's really the only thing I use my mac for.

[Trilska]

Nice to see the Kelly working so fine together with the turnigy 80 100.

I am in the planning stage of a project including the same motor and a Kelly keb esc. Did you go for the esc upgrade to enable higher electrical rpm? Also what Kv do you get out of your motor?
/Trilska

[bose]

I really like the simplicity of your build! Seems as if it works well too

Which bottom bracket and cranks did you use? Is it the same ones as in the cyclone kits?

Great work!

[mauimart]

Nice to see the Kelly working so fine together with the turnigy 80 100.

I am in the planning stage of a project including the same motor and a Kelly keb esc. Did you go for the esc upgrade to enable higher electrical rpm? Also what Kv do you get out of your motor?
/Trilska

I did order the high speed firmware upgrade (70,000 eRPM). The estimated kV for the motor is around 70 which gives me in the neighborhood of 4900rpm at full throttle. The firmware upgrade will be put to the test when I install my stock 80-100, 130kV. The plan is to get some more testing in with the more docile 70kV motor before I expose the Kelly to the higher loading of the delta wound 130kV.

I really like the simplicity of your build! Seems as if it works well too

Which bottom bracket and cranks did you use? Is it the same ones as in the cyclone kits?

Great work!

The cranks, crank freewheel, chainrings, and bottom bracket are all from sickbikeparts.com. I went with the 153mm Bottom Bracket Cartridge to get the required crank clearance. I think the crank freewheel is a White Industries unit and might be better quality than the cyclone version - I'm not sure. I don't know if the bottom bracket and cranks are the same as the cyclone kits.

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[Andje]

yes that WI freewheel is better, still suffers because of the additional side load all the engine torque puts on the chain, but it's definitively a standard quality upgrade.
If i had gone rc i think this would have been exactly my route, although i think you did a much better job then i could have. I do kind of miss the feeling of shifting threw gears like a motorcycle... Amazing video!

[Jay64]

I know this is a little late, but nice build. Any updates to it recently? You had mentioned that the suspension wasn't up to par. You could probably just upgrade just the suspension. I've been looking into some of that stuff and have found some stuff for pretty good deals on ebay lately.

Where is that video taken? Looks like somewhere up country like Pukalani or Kula.

[mauimart]

I know this is a little late, but nice build. Any updates to it recently? You had mentioned that the suspension wasn't up to par. You could probably just upgrade just the suspension. I've been looking into some of that stuff and have found some stuff for pretty good deals on ebay lately.

Where is that video taken? Looks like somewhere up country like Pukalani or Kula.

Just the other day I dismantled the prototype setup to begin the "cleaning-up" phase. The reason it took so long is that I was having too much fun riding it around the yard
I have also been working on refining my Arduino based instrumentation/logging system (see photos). It's currently installed on my build #1 and is working quite reliably. In addition to displaying the critiacl e-bike parameters, similar to cyclye analyst, I have it logging the data to an SD card. There is still one bug I need to resolve. For some reason when the SD card is installed, the distance and wheel speed data is a bit off (1 to 2%). I think it has to do with the interrupt activated by the wheel sensor causing timing conflicts elsewhere in the code. It's spot on when not logging data. It stores the data in an Excel friendly csv format for easy analysis and plot viewing.

I will most likely upgrade the suspension at some point. I just hope the headset is compatible with the standard size of forks these days. This was not the case on my first build, chrome-moly Bridgestone which desperately needs front suspension as I'm cruising at 40 to 45mph with 85lbs of weight plus rider.

Some updates:

I purchased and modified a Topeak seatpost rack that I plan to mount the oversized kelly controller on (see photo). I may even locate the controller on the bottom side of the rack if there is enough clearence between the tire and controller. Plan to add fenders later as well. In any event it's not the ideas location for the controller as the phase wires to the motor will be rather long.

I think I have finally decided on the batter pack. Six pieces of the Turnigy 6S 5000mAh 20C bricks for a 18S2P setup (66.6V, 10Ahr). I plan to locate the batteries in the top part of the triangle (see photo). I will have to fabricate some sort of rack/box/enclosure. Anyone have any ideas?

The SRAM integrated brake lever/shifter that came with the bike needs replacing. In its current configuration I cannot shift the rear derailleur and operate the throttle at the same time. I think I may have found a lever-type shifter replacement on ebay that may be compatible with the 8-speed SRAM cassette.

Oh, and the video was taken in Kula.
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[mauimart]

I put together a rough mock-up of my proposed battery box using cardboard. I may make it a little bigger toward the bottom so that if I come across a smaller controller I can also fit it in there with the batteries. One side of the battery box will be accessible via a hinged flap or removable panel using quarter-turn fasteners. I'm thinking of using 3/32" aluminum sheet for the box and bending as much as possible and then brazing the rest with HTS-2000 brazing rods. I've had decent success in brazing two pieces together at a right angle. Under load I have not been able to break the joint. Instead the material just bends. Seems promising.

[AussieJester]

Nice welds mate this things going to piss! hope you got some decent protective gear!

KiM

[adrian_sm]

I have also been working on refining my Arduino based instrumentation/logging system (see photos). It's currently installed on my build #1 and is working quite reliably. In addition to displaying the critiacl e-bike parameters, similar to cyclye analyst, I have it logging the data to an SD card. There is still one bug I need to resolve. For some reason when the SD card is installed, the distance and wheel speed data is a bit off (1 to 2%). I think it has to do with the interrupt activated by the wheel sensor causing timing conflicts elsewhere in the code. It's spot on when not logging data.

1-2% isn't much. How can you tell?

In my Arduino code I have an interrupt on the wheel sensor. The interrupt function then just increments distance by wheel circumference, and creates a time stamp, and exits. This strategy appears to work fine even with SD data logging. But maybe I just haven't noticed a small error.

- Adrian

[Jay64]

Hey, I'm coming back home to Maui in a couple weeks. Would it be cool if I stopped by and checked out your builds? My mom still lives just down the hill from you out in Haiku.

[mauimart]

I just picked up one of those cheap Hua Tong controllers for $37. It's rated at 72V, 1500W, at least that's what the sticker says. Thought I would hook it up to my rewound Turnigy 80-100 while the bike was in maintenance mode. Under no load the cheapo controller makes the motor scream. I got it up to around 6000 rpm and it seems to run smoother than with the $400+ Kelly. No telling how much power it will handle under load but once I get my battery box complete I will have to give it a full test. Here's a short video of the test:

[mauimart]

I finally made some progress on the build. I partially welded the battery box - first time using a TIG. The box is a bit wider than I first envisioned. It will now hold 9 pieces of the 6S, 5Ahr Turnigy Lipo packs. I initially plan to run on just six packs for a 18S, 10Ahr pack but will have the capability to expand to 18S, 15Ahr. As far as the box goes I need to cut out the rest of the aluminum pieces for the back, front, and bottom and then weld in place. I have some of that faux carbon-fiber adhesive that I may cover the box in for a different look. Any comments on the look? See pictures. I also installed some of the phase wiring.

[AussieJester]

This is looking very very good! i think your going
to be extremely pleased with the performance
looking forward to video and hearing your impressions
after thrashing it for a bit hehe...

KiM

[mauimart]

This is looking very very good! i think your going
to be extremely pleased with the performance
looking forward to video and hearing your impressions
after thrashing it for a bit hehe...

KiM

Thanks KiM. My inspiration comes from what you are able to produce using a simple right-angle grinder. What a versatile tool.
Still a ways to go before I can begin thrashing it. I still have to order the batteries to populate the box...
Here's another pic showing how the bricks tightly fit in. Pending build completion, a video will certainly be produced.
Martin

[mauimart]

A bit more progress today... Finished welding the box and installed on bike. Cut out the access hatch. I'm thinking maybe hinges and and some neodymium magnets to hold it shut. I still need to mount it to the top tube. Also need to mod it a bit as I have some interference issues when the rear shock compresses.
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