Considering a build: I have an Electra Townie Step-Over Men’s 7D bike, a Crystalyte 5304 direct drive rear hub motor, and a 72 Volt battery. Would like to mount the battery inside the frame if possible without dismantling the battery. The battery size is 4” x 5 1/2” x 7” each. There are 2 of them that make the 72 volts together. (See Picts.) Any ideas? Thanks,
72 Volt Electra Townie Rocketship
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Chalo
100 TW
Can the BMSes on those packs tolerate 70-80+ volts across the leads? If not, you're setting yourself up for failure by putting them in series.
I've electrified a number of Townies and similar bikes, but I would never set one up to go faster than high 20s mph.
I've electrified a number of Townies and similar bikes, but I would never set one up to go faster than high 20s mph.
The battery and motor came from Lithium Batteries, DYI ebike conversion kits, Crystalyte Motors and Electric Bikes, Electric Scooters and was already in use on a Giant Sedona. The previous owner said the bike would go around 40-45mph. I figure if the Giant Sedona frame could handle the power which has a shorter wheelbase than an Electra Townie, then the Townie should be able to handle it.
Chalo
100 TW
You can make a Radio Flyer red wagon go 45 mph, but that doesn't make it a good idea.
Townie is a bike designed for slow casual riding, that can be ridden confidently at somewhat higher than its design speeds on good surfaces. But there are limits. The steering geometry won't settle into a groove at traffic speed like a motorcycle or a downhill bike, because that's not what it's for. It's difficult to impracticable to stand up on the pedals, so both the bike and your spine will get hammered out of shape by road hazards that sneak up on you when you ride at abnormal speed.
You do you. But unpleasant consequences are easily predictable if you try to make a fooling-around bike path bike move at motor traffic speed.
Just because it will go 40-45mph doesn't mean I have to drive it that fast. The main reason why I'm considering building it is to be an economical build. I got a good deal on the Giant Sedona DIY eBike. It is old technology but was the some of the best at its time. It has a 72 volt battery that is good and a 5304 Series Crystalyte Direct Drive Rear Hub Motor that is good as well. The controller and the display on the other hand is not and would have to be replaced. The controller (X-CT7240F) is a 72V - 40A Crystalyte 7240F controller with a Cycle Analyst display. Does anyone know of a controller and display I could use now that would work and replace the bad controller and display? Thanks,
Chalo
100 TW
It's a mistake to set up an EV to go much faster than your anticipated speed. To do that, you have to set up the whole system for more power (weight, expense, temperamental parts) than if you built it to go as fast as you want but not more. And then you end up running the thing in a lower efficiency regime because the sweet spot is at too high a speed.
Stinking gas cars thrive when they loaf at well below their capabilities. But EVs work best when they're run at close to their maximum speed as much as possible.
You got a link to your Townie build?
Turns out it is looking like the Cycle Analyst is fine. It is looking like the BMS is shutting things down to protect the system. The Cycle Analyst comes on for a couple of seconds then shuts off. Looking like it is a bad controller. Sound about right?
Chalo
100 TW
No, but I've done several for friends (including my wife) and several for customers. My honey's is actually a KHS Smoothie, but they're all the same fundamentally. I'll try to get photos when the sun shines. But my usual formula is a front Jump bike front hub motor, maybe or maybe not with its original rim, plus a KT 22A controller and LCD4 display, and a secondhand brick battery from some unknown medical or data center equipment.
My favorite layout is a sturdy nylon handlebar basket to hold the ~10 lbs battery, with the controller attached to the back of the basket. On others, I put the battery and controller in a rack top trunk. There are advantages and disadvantages to both.
Dual suspension and very large brakes ( super oversized vbrakes or 203mm disc ) is the bare minimum of what you want above 30-35mph.
These cruiser bikes aren't built with speed at all in mind, but mountain bikes are. A typical mountain bike will have both the suspension and frame strength you're looking for at >2x pedal bike speeds.
A MTB with dual suspension and proper geometry only starts getting skittish around 50mph. It's kinda built for that.
I agree with Chalo that a motor is best run near it's top speed.
These cruiser bikes aren't built with speed at all in mind, but mountain bikes are. A typical mountain bike will have both the suspension and frame strength you're looking for at >2x pedal bike speeds.
A MTB with dual suspension and proper geometry only starts getting skittish around 50mph. It's kinda built for that.
I agree with Chalo that a motor is best run near it's top speed.
