MIT student named Charles Guan
On his blog, Charles states that Chibikart took him a total of three weeks to build, “from [announcement] to first ride test,” which seems like just absolutely no time at all.
I reached out to Charles via email, curious to find out how much a project like this would cost a person…
The battery pack was an exclusive that he was given at no cost, but it’s not on the market. “An equivalent lithium ion battery of that size is about $US250 to $US400 depending on quality/grade. ($250 for two model aeroplane batteries, and for a vehicle grade pack.)”
“The motors have about $250 of materials and machining time put into them,” — which, with a total of 4 motors, is another $US1k of expenses — “but it’s not a cost I paid directly,” Charles explains, “because I already had many of their parts.” Factor in about $300 of “direct frame material and hardware costs” and a scratch estimate would put the cost to build the Chibikart at about $1300. (With the caveat that the battery cost isn’t really known.)
Building a Chibikart from scratch, if you don’t already have some of these parts, could set you back as much as $1750 (factoring in the higher-cost equivalent lithium ion battery).
He documents the whole assembly, tweaks and setbacks and all. So I fully expect a fleet of copycat Chibikarts to appear in the coming months. Which would be great. Especially if someone built one for me.
• Frame size: 34″ by 18″
• Motors: Custom-wound and packaged direct drive hub motor, 300W peak each*
• Wheels: 100mm 87A skate wheels
• Battery: 32v 9Ah lithium iron phosphate pack
• Controllers: 350w-class Mysterious Chinese Sensorless e-Bike Controllers (“Jasontroller”)
• Top speed, theoretical: 26mph (voltage & motor RPM/V & wheel diameter)
• Top speed, realistic: 21mph**
• Actual top speed: To be determined.
*30 second “peak” rating at 20 amperes
**Factoring in conservative estimates for air drag, and motor resistive losses at-speed, smooth and level ground assumed.