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Project Spotlight: Electric Motorcycle

May 23rd, 2012 3 comments

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Last week, Hive13 member Rick showed off a rather impressive project: An electric motorcycle he’s building. He started it near the end of 2011, inspired by his father who started building an electric car years back but due to funding issues could not complete it. A lot of online resources helped greatly by providing information on what people had tried, what worked, what did not, what parts they were using, and so on. (Did I really need to mention that part? This is a blog for a hackerspace.)

Whatever its stage of completion, he says he has about 100+ miles on it so far and it can do 54 mph. (Update: This doesn’t mean the bike has a range of 100+ miles, but that he has ridden about 100+ miles on it so far. Actual range is more like 20 miles. Sorry, Hackaday.)

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The frame of the bike is a 1989 Honda VTR 250 he had around for spare parts for other bikes. To replace the Honda’s 24 HP gas motor, he used a common golf cart permanent magnet DC motor, 24 V – 72 V, driving it with a fairly standard 48 V electric controller. Four Optima Deep Cycle Yellow Top 12V batteries power it (two of them are visible in the top photo), and he added a 48 V charger to manage them. (Update: Batteries are AGM [Absorbed Glass Mat], not lead acid, for the record.)

Headlights, taillights, turn signals, and other accessories run from 12 V that a DC-DC converter provides. (I think this also included the ridiculously loud horn, strictly for safety reasons because the bike makes practically no noise otherwise. He says he’s only had to use it twice so far…)

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Rick estimated the total cost at about $2800, and that was using mostly new parts with warranties rather than used ones from Ebay. In addition to this, he purposely built it with a removable battery rack if we wishes to swap in a different battery type later on – he mentions LiFeMnPO4 batteries and a new controller & charger that would have added $1500 to the price, but would have increased the bike’s range and reduced its weight. (He put its current weight at about 400 lb total.)

Actual problems seemed pretty minimal. He made a mistake in the math when choosing the motor’s drive sprocket; a recent change in this brought the top speed from 35 up to 54 mph. The website from which he bought the battery charger advertised it as weatherproof, and he discovered it was not. He has some concerns about the motor getting too hot on hills or longer runs, and intends to add a temperature gauge and a fan.

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I also felt I had to ask a token stupid question, “What is it like to ride a motorcycle where you can’t rev the engine?” but received a fairly serious answer: “It’s weird not having a gas motor. The rev thing isn’t as weird as not having any kind of engine brake when you’re going down hills.”

The Flickr album of pictures is here (first 5 are courtesy of Dave Myers; remainder are my own until the last 5, which are Rick’s). Rick also provided some photos and videos of the initial tear-down, assembly, and first rides:

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(Disclaimer: Neither Hive13 nor Rick advocates riding without protective gear. The only reason this is absent in the pictures is that these were very short test runs.)

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