Extending The Range Of An Electric Bike

Cruising around town on your electric bike is surely a good time…. unless your bike runs out of juice and you end up pedaling a heavy bike, battery, and motor back to your house. This unfortunate event happened to Troy just one too many times. The solution: to extend the range of his electric bike without making permanent modifications.

Troy admits his electric bike is on the lower side of the quality scale. On a good day he could get about 15 miles out of the bike before it required a recharge. He looked into getting more stock battery packs that he could charge and swap out mid-trip but the cost of these was prohibitive. To get the extra mileage, Troy decided on adding a couple of lead-acid batteries to the system.

The Curry-brand bike used a 24vdc battery. Troy happened to have two 12v batteries kicking around, which wired up in series would get him to his 24v goal. The new batteries are mounted on the bike’s cargo rack by way of some hardware store bracketry. The entire new ‘battery pack’ can be removed quickly by way of a few wing nuts.

Connecting the new batteries to the stock system go a little tricky and the stock battery pack did have to be modified slightly. The case was opened and leads were run from the positive and negative terminals to two new banana plugs mounted in the battery pack’s case. The leads from the new batteries plug right into the banana plugs on the stock battery pack. The new and old batteries are wired in parallel to keep the voltage at 24.

Troy found that he’s getting about twice the distance out of his new setup. Not to bad for a couple on-hand batteries and a few dollars in odds and ends.

Hackin’ the junkyard: Electric scrap bike projects

[Brad Graham] wrote in to let us know about his electric bike data dump over at atomiczombie.com, written just for us! Last we heard from [Brad] he was building some serious robots and freakishly tall tallbikes but since the weather has turned for the chilly its time to focus on indoor projects. Using a combination of robot parts, electrical conduit, and OEM bikes for the frames [Brad] takes us through several of his builds and all the various complications trying to drive the (often very powerful) electric motors. The builds range from scrapping motors and controllers to full blown drop in hub motor systems that can combine human and electric power. There is even an electric pusher cargo cart designed for a cooler, because beers are not going to haul themselves around.

Don’t forget to check out the AtomicZombie website for a ton of useful tips to chopping up bikes for your own mutant transpiration projects, we know we will. Thanks [Brad]!

Human electric trike project


While I’m waiting for my last stepper motor, I’ve been pondering my electric motorcycle build. While eyeballing batteries, I ran across a really impressive human/electric recumbent bike project. [Bob Dold] built this for his M.S.M.E. Thesis project. The frame was built from bonded aluminum. The flat parts were cut via waterjet service, and the rest were machined by the college’s machine shop. The 1000w motor (and controller) came from a Schwinn X1000 electric scooter. Looks like a four link suspension (plus steering and shock linkages). Interestingly, he’s using some USB data loggers for voltage and current(with a shunt) and combining it with GPS data to track real world performance.