Building a fast 500w 'stealth' bike

[laslooo]

Hi guys - I'm new and would love some help to get started. In Berlin, Germany where I'm from there's tons of bike thieves AND nasty government laws that restrict ebikes to maximum 500w engines and 45 kph.

That's why I want to build a stealth ebike that could be mistaken for a regular bike, at least on first sight >> less police checks, less thieves, can use bike lanes if needed.
(I love Keplers Super Commuter...)

So this is what my dream ebike would be like:
- 500w, max speed of around 50-60 kph,
- quiet motor and battery pack that are not too obvious
- built for mostly flat terrain
- as much range as possible
- budget maximum 600-700$
- has a battery pack that I can take out easily and use later to also power my longboard

I appreciate your help! Thanks so much

 

[Wheazel]

Welcome to the ES!

Without getting into very advanced stealth solutions like integrating stuff in frames etc, i think that a small hubmotor in the rear wheel is a good compromise between stealthy and cheap.
And having the ability to go 45km/h legally is crazy nice. Here in Sweden its 250w/pas/25km/h no matter what, if you want it to be classified as bicycle.
500W will not get you to 50-60km/h on its own. You would need about 1kW for that on a reasonably efficient bikeshape.

With the few criteria given, I would get a smallish hub, gear for ~55km/h, and use a cycle analyst for limits/monitoring.
To power both the bike and longboard with the same battery is a tricky one. I am just seeing unbeneficial compromises on this one.
Maybe a backpack battery? Stealthy but with drawbacks.

 

[dogman dan]

Dream on bro. Re the stealth, you can hide the geared 500w motors such as the Mac, or similar motors behind rear gears on one side, and the disc on the other side. But believe me, ride those geared motors close to 50 kph, and they WILL hear you coming.

More silent, and able to go faster direct drive motors are obviously a motor. But you can hide a big motor behind some large panniers or saddlebags, like this.
Hang the bags a bit lower, and nobody can see that motor from the side. I hung them where I did, because I need no stealth here, 30 mph is legal where I live.

Carrying the battery in those saddlebags helps stealth too, it doesn't look like an ebike, without a frame battery or bag.

Till they see me going 35 mph, nobody thinks this is a motor bike. But then again, nothing stealthy at all about doing 56 kph on a bike.

My best advice though, is plan on a bit slower bike. Then you won't stick out so much riding it. Build a standard 48v 1000w direct drive setup, with max speed somewhere around 45-50 kph. And hide the rear motor behind some bags. BTW, the 500w dd motors easily handle the 1000w controllers that make them able to go 45 -50 kph.

You'll be plenty fast at 45-50 kph, and almost actually legal. You'll only be illegal when the battery is really full.

As for the budget, keep on dreaming. Likely you will need to spend closer to $1000 to $1500, much of that on a good battery. But you can get what you want from a cheap ass 48v 1000w motor kit.

 

[laslooo]

thanks for your replies guys, appreciate the help and advice. I will definitely get a hub motor.

For the bike to be stealthy I'm currently considering two options:
>> Option A) Build controller and battery into a pannier and make the whole thing easy to plop in and out. Will that be hard to do?
>> Option B) Find a bottle shaped battery pack and a small controller that can be hidden somewhere on the bottom of the bike or something like that.

What do you think about those options? Which one will be cheaper? Advice? What problems will I face? Specific gear suggestions?

Also I read somewhere it's possible to build a switch into the controller or somewhere so that you have different modes, like maximum 25 kph, 40 kph, and 50 kph? How do you do that?





I'm super excited to get started. cheers!

 

[leo99]

Hi lasloo,
time to come and look at your build.
option A for heavier build would be easier to do and would make hiding the motor much easier if the motor is bigger then the cassette. If you want 50km/h and range it seems like the best option. a Mac motor from em3ev and battery on each side of the pannier sounds good but will be heavy.

option B would be good for lighter build smaller motor q100h or q128h. less speed 35- 40km/h and less range if you really want the battery to be stealthy. it would handle better and pedal better

I think it really depends what you are looking for.
would you really pedal all the time or just a bit ?

 

[dogman dan]

Too much stuff to unplug and plug all the time, and, smothering controllers in bags can overheat them.

Just hide the controller, like between a fender and the rear rack. then when you attach panniers that hide the motor, they also hide the controller and 90% of the wires.

Battery of course, carries in one or both panniers.

It will look like a regular bike, till somebody really squints, and sees your twist shifter looking thing is actually a throttle. That is, till you are going 45 kph on it. Then it will look like a speed ebike.

 

[friendly1uk]

An old beat bike gets a lot less looks from thieves and is less likely to be electric than a modern bike.

 

[Tiju]

Hi there
I am looking to build the same thing, have you had any progress? Any other good resources maybe?
Cheers!

 

[dogman dan]

Nothing has changed,, cheap bike thieves won't like, hide the motor behind some saddlebags or panniers.

Easy to unplug the battery and take it with you. The rest, go with a cheap ass kit so its not that much money when you lose it. then try not to park it anywhere it will vanish.

Budget of $1000 usd more like what you will end up spending.

 

[skeetab5780]

They used to make smaller sized DD brushless hubs I owned one on a liberty electric 36v bike and it wasn't that bad. I think Golden motor/conhismotor and also Crystalyte used to have one(the 408). These will be easier to hide and if your really only going to use 500w they will handle it no problem.

I do not like geared motors because they are too loud. They remind me of the old Heinzmann hub on the EVG Ebike

 

[melodious]

Depends on how you interpret "loud". Those new to the scene, a geared motor is near silent, up until you compare to a direct drive. But wind noise cancels the geared motor sound quickly once you start rolling.

I think Kepler's FD is a great way to start. But you need to fit certain requirements for it to work.
1. You can only ride it in dry weather days (really not a commuter if it won't). Just get a 2nd ebike for that.
2. It fits lightweight road bike frames. Don't fool yourself that it's a utilitarian vehicle (cargo bike). But most trips, we aren't overpacking (more than what a backpack could carry) stuff to haul.
3. There is a buzzy whir noise that might not appeal to some. I find the noise kinda "futuristic" compared to the dead silence of other systems. This might be remedied soon with the right ESC. :wink:
4. You need to know how the system works. I think it's a great start to those wanting to learn about the application of hobby RC components into a bicycle's workings. You'll learn a lot of RC battery techniques that can be applied further down the line for more powerful builds.
5. You'll be using more of your own pedaling input. This isn't a "lazy man's" bike where you get assistance at every pedal rotation. You learn to apply power where it most suits the road.

 

[fechter]

Using a sine wave controller will reduce the noise of most motors significantly.