Paul Barnfather

BMW i3 94Ah cells

More ideas from today’s workshop session. It appears BMW i3 94Ah cells would be ideal! 😀 30 cells would give me 10.5kWh at 111V – in only 60kg. Here’s an approximation of 6 of them stacked together: Even so, it’ll be a bloody tight fit! The battery box and cabling will be {ahem} interesting…

Software first

While I’m still developing ideas for the hardware, there’s nothing stopping me from pressing ahead with the software development. Behold: my GitHub repository! Not much there yet, but I will begin by working out the features and logic needed for the main control loop. The plan is to test the complete system on the bench …

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Back to school

I’m thrilled to be joining the Electric Car Conversion Course that’s being run by New Electric in March 2020. The course was sold out in 4 days! Do check out what these guys are doing over at

Drive options

I’ve got three options for the final drive: 1. Concentric belt drive through the swingarm pivot. 2. Chain drive from motor shaft (in same place as existing pinion). 3. Motor onto gearbox input shaft (in same place as existing clutch). The first one is the most desirable, but would mean fabricating a new swingarm and …

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Outline spec

Having ridden the bike a bit, an outline specification is forming in my mind. The bike is quite light, but somewhat underpowered (it has ~30 bhp). I’m thinking a 40kW motor should be about right, with up to 100kg for the battery pack.

It’s home!

Here it is arriving after a 200 mile ride from Durham through awful weather. On petrol power, natch. It never missed a beat and got nearly 70 mpg – not bad for a 30 year old bike.