Author Topic: Cheap Electric fatbike  (Read 24749 times)

DavidJohn

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Re: Cheap Electric fatbike
« Reply #30 on: February 19, 2016, 04:19:29 AM »
Just buy a normal fatbike.. and use your legs..  ;D


Eagle

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Fast is FUN!   8)
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PonoBill

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Re: Cheap Electric fatbike
« Reply #32 on: February 20, 2016, 11:45:16 AM »
It's feasible to design an in-bracket motor that would be very hard to detect. What I see the regulating bodies using for detection would be easy to defeat. Even pulling the bottom bracket apart wouldn't be apparent. Design the PAS to give a boost only at the highest level of effort. No external controls, no wires, no visible motor or battery. I could do it, that means others can.
Ponohouse is for sale: http://www.ponohouse.com
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Eagle

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Re: Cheap Electric fatbike
« Reply #33 on: February 20, 2016, 12:19:04 PM »
http://www.businessinsider.com/vivax-motor-bike-doping-scandal-2016-2

"You can download in the App Store an app for magnetic search," he said. "With a simple app you can find the motor, because the motor is [made] from steel and the frame is carbon. You can see the difference in the material."  - But like the Lance fiasco -> staying one step ahead is the goal - and can work for a while.

Fast is FUN!   8)
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PonoBill

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Re: Cheap Electric fatbike
« Reply #34 on: February 20, 2016, 05:20:16 PM »
Yeah, I wouldn't do that. Embed uncored copper coils in the carbon bottom bracket. Make the crank axle a large diameter tube with low profile bearings and groove it radially. It could just look like a trick, lightweight part even if the entire crankset was disassembled.  Batteries in whatever tubes you decide on. Leave the thing unpowered until high cadence is detected (passively, from induced voltage) and then power up the thyristors. Marginally detectable because of the reluctance difference of copper coils vs carbon, but not easy like a steel can or iron cores would be. Wouldn't be the most efficient motor available, but should be good for a couple hundred watts. Used to be that some electric motors for toys and cheap clocks were made this way.  Modern coreless DC motors are a different thing, using easily detectable permanent magnets. This is a synchronous AC motor I'm conjecturing about.
« Last Edit: February 20, 2016, 05:33:13 PM by PonoBill »
Ponohouse is for sale: http://www.ponohouse.com
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

PonoBill

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Re: Cheap Electric fatbike
« Reply #35 on: February 20, 2016, 05:27:59 PM »
Just buy a normal fatbike.. and use your legs..  ;D



Nice, but i notice you stay in the wet, packed sand. Mine will zip over the dunes like a trail bike. Nice to have a couple of lance Armstrong's shoving you when you need it.
Ponohouse is for sale: http://www.ponohouse.com
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

GOTWAVZ

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Re: Cheap Electric fatbike
« Reply #36 on: August 05, 2016, 09:34:12 AM »
I tagged this onto the downhill video, but shouldn't have. Just being lazy.

Here's my latest project. Built this yesterday. It's a cheap fatbike ($250 from K-Mart) mated to a REALLY good Chinese crank drive electric. These Bafang BBS02 drives are beautifully engineered. This is the new 100mm, version that fits most fatbike bottom brackets. I had to cut 15mm off my braket to fit it, which would be shameful with an expensive fatbike but for $250 it's no biggie. The power electronics are in the drive, so there's just one waterproof harness for the control circuits, one for the battery and one for the speed sensor. Super clean installation and a TON of power. 1200 watts peak, 750 continuous. Highly configurable and very good UART control system (tons of info available on line). Or just stick it together and ride with default settings (like limited to 20MPH). Super powerful, especially with the seven speed gearing on my cheapo. Even has discs. 

The 100 mm versions are hard to come by here, no one wants to ship them to Maui, so I bought 11 of them straight from Bafang and imported them. If someone wants one on the Hawaiian Islands I'll sell it to you at my cost. I don't know exactly what that is, but it's somewhere around $600. I had plans to do something exotic with them, but other priorities arose. If you're on the mainland you can get these pretty easily for about $700, but be sure you're getting the right length for the bottom bracket. Standard is 68mm, but most fatbikes are either 100 or 112.

Got to be the cheapest way possible to build an electric fatbike with a quality drive. I'll never build another hubmotor bike--too clumsy. The K-mart here in Maui has three of the model I used left in stock.









I'm using three 14.8 V 5000ma RC LiPos to power mine. Super cheap way to do a fatbike battery if you already have a 4 channel LiPo charger. I already had four of the batteries for multicopters.  The photo shows 4 but I had to drop to 3--the drive errored out from overvoltage. Nice that it just says "sorry, can't do that" instead of just toasting. I'm eventually building a set of three batteries that will sit in parallel with two sets diode-isolated and one switchable as a spare. With 15 amps at an actual 50V it should give a lot of range. . 750 watt/hours, or about an hour at full power. More like two hours at 20 mph. Kind of bitchy to charge, but a few hundred bucks less than a standard bike battery and much lighter.

Alright Bill....your a bad influence on me...I just bought two of everything...but went to Lunacycle and got the Bafang BBSHD 1000 Watt Mid drive kit, full color display, Carbon Shark 52 v GA 13.5 ah battery.....starting the build later today.....let the fun begin
HB, CA, Oahu, HI
JK 7'-8' x 28"x 4" = 99L
JK 7'-10" x 41/4" = 106 L
Joe Blair Gun 8-10" x 28 x 4 1/4
198 lbs - 5'-9"

PonoBill

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Re: Cheap Electric fatbike
« Reply #37 on: August 05, 2016, 09:41:00 AM »
Hard not to like. Here's my latest. I just built a 48v 16AH battery for it.



You might have to trim the bottom bracket, depending on which length BaFeng you bought. No big deal, just hacksaw it off the non-chain side.
« Last Edit: August 05, 2016, 09:43:57 AM by PonoBill »
Ponohouse is for sale: http://www.ponohouse.com
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

Beasho

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Re: Cheap Electric fatbike
« Reply #38 on: August 05, 2016, 09:48:51 AM »
Hard not to like. Here's my latest. I just built a 48v 16AH battery for it.

You might have to trim the bottom bracket, depending on which length BaFeng you bought. No big deal, just hacksaw it off the non-chain side.

Fragging cool!  How much does this version weigh? Between this, the foils, the SUB foils . . . too much to do and maintain the job and family priorities.

PS: If you haven't tried an electric bike you have to try one.  They are like riding a magic carpet.  I have yet to put someone on my electric bike, young or old, who hasn't giggled with delight at the silent, mystical power it delivers.   
« Last Edit: August 05, 2016, 09:59:36 AM by Beasho »

GOTWAVZ

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Re: Cheap Electric fatbike
« Reply #39 on: August 05, 2016, 09:57:26 AM »
Hard not to like. Here's my latest. I just built a 48v 16AH battery for it.



You might have to trim the bottom bracket, depending on which length BaFeng you bought. No big deal, just hacksaw it off the non-chain side.

very clean...whose front fork did you go with? that will be my first upgrade I think....then racks....one for kiting...one for supping.
HB, CA, Oahu, HI
JK 7'-8' x 28"x 4" = 99L
JK 7'-10" x 41/4" = 106 L
Joe Blair Gun 8-10" x 28 x 4 1/4
198 lbs - 5'-9"

PonoBill

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Re: Cheap Electric fatbike
« Reply #40 on: August 05, 2016, 10:14:01 PM »
I kind of hate to tell you this, but I'm building an electric Triumph TR3.

Oh, and 5000mah batteries are a dirty lie. More like 1200mah, but at less than a buck apiece, I just keep welding then together until I get what i need. Honestly, I can't tell what the cheap Chinese batteries are--they're all over the place. Some are 1200mah, some are 3000mah. None are 5000mah, but just stick a whole bunch in parallel and who cares.

You did the right thing buying from Lunacycle. In a world of sleazebags, those guys are the real deal. Congrats on your wisdom.
« Last Edit: August 05, 2016, 10:19:46 PM by PonoBill »
Ponohouse is for sale: http://www.ponohouse.com
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

linter

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Re: Cheap Electric fatbike
« Reply #41 on: August 06, 2016, 02:51:43 AM »
  Has anyone come up with the better design for a SUP rack?  Beasho's works for him but that style caused me nothing but trouble with my super-heavy, very-wide 10' board.   I've looked at some of the commercially available trailer-types and I'm sure they're fine but, well, there's nothing elegant about them.  And I want elegance.   Pono -- you gotta put your teeming genius mind to work on this at some point.

PonoBill

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Re: Cheap Electric fatbike
« Reply #42 on: August 06, 2016, 08:40:34 AM »
Project #1164.

Actually, I made a pretty good trailer for my motorcycle in Maui, but it's a fair amount of work to make.
Ponohouse is for sale: http://www.ponohouse.com
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

JP4

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Re: Cheap Electric fatbike
« Reply #43 on: August 19, 2016, 08:23:28 AM »
Hey PB, just read about this. Is it legit? Seems like a revolution in batteries if scaled up.

http://news.mit.edu/2016/lithium-metal-batteries-double-power-consumer-electronics-0817

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PonoBill

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Re: Cheap Electric fatbike
« Reply #44 on: August 19, 2016, 08:49:31 AM »
Yes, it's for real, and it can scale. Tesla's gigafactory is a multi-chemistry system, they can adapt it to almost any battery design. Improvements in batteries are coming fast and furious. Even just the new size cylinder batteries and the advanced Li-ion chemistry that the gigafactory is producing are nearly double the power per kilo and double the expected life that batteries produced previously.
Ponohouse is for sale: http://www.ponohouse.com
Foote 10'4X34", SIC 17.5 V1 hollow and an EPS one in Hood River. Foote 9'0" x 31", L41 8'8", 18' Speedboard, etc. etc.

 


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