Buillding a new setup for long distance - advice please

[trietje]

Hello all fellow e-bike drivers,

For the moment i have two ebikes (1 recumbent and one folding Dahon) with Bafang 36V engines. They drive 25 km/h both with 36 V LiFePO4 battery.
I have them for 2 years now and am satisfied, but want greater speed now for long distance drive (+120 km) within reasonable time and also bigger driving comfort.
These 'planetary' engines are hard to upgrade to higher speeds, so i let my eye fall onto another engine, the Crystalite HS 3540.

For long distance i want to be able to drive about 50( eventually 60) km/h. has to be foldable bicycle. Is that still safe for bicycle at
these speeds? I also take disk brakes. Seems necessary at these speeds.

I let my eye fall on:

Dahon Matrix: that folding bicycle has only rear suspension. Is full suspension necessary at these speeds and driving distances for comfort?
I would make it a front engine, because the batteries come on rear rack. Or is rear motor a better option for some reason?

Connections/soldering between components: where and what to order?

Ping batteries: 2 x LiFePO4 48V 20 Ah? Or would 2 x 15 Ah do for 120 km drive at these speeds?

Controller: do i need special controller for these speeds, or will the controller do that comes with the motor?

options? It has to be a pedelec, so 3-way speedcontroller? drive sensor on the pedals? Regeneration through braking?

weight: bicycle 13 kg + motor 7.5 kg + 2 x 20 Ah batteries makes 35 kg ... heavy to take on the train.
So if 15 Ah batteries would be possibel i gain 5 kg on the batteries. It makes a total of 30 kg then.

One battery pack on top of rear rack (which one to buy?), on battery on side. Backpack on other side, so it can be taken off when
folding the bicycle together.

I would like some advice on all my ideas. I am sure they can be fine tuned by a lot of people here.
Also where to buy for best quality/price. I am in Belgium.

Thanks in advance,

trietje :lol:

 

[d8veh]

I think you've under-estimated the weight a bit. My calculation says a bit more like 45kg. The thought of all that weight and power on small thin wheels scares me. Can the folding mechanism deal with that weight. Most folders are rated at about 100kg load, so, if you're about 60kg, it might be OK. I have ridden powerful motorcycles all my life. My present electric bike is a 350w Bafang Giant NRS with full suspension and 26" x 1.95 tires and I wouldn't want to go any faster than it's 35km/h on it. Have a look on this forum at the pictures of the bikes that can do a sustained 50km and you'll see that they're more like electric motorcycles. In my opinion, if you reduced your target for cruising speed to 35km/h, you'd have a better chance of achieving it.

 

[dogman dan]

I've built quite a few ebikes in the last three years, trying various types of motors on lots of types of frames.

One thing stands out in capital letters. To carry lots of weight, you need a strong stiff frame. It needs stiffness from side to side, as well as top to bottom. What happens, is you inevitably end up putting a lot of the weight into panniers. Then the bike will wag it's tail. On weaker bikes, like the cheap mtb's with aluminum frames, that tail wag will be quite excessive once you load it up.

So I think the folder is the wrong approach. A few things do work. High end DH full suspension bikes have really strong frames to huck jumps. My commuter is made from a mid price one, and carrys 50 pounds in the panniers quite well.

Even stronger and stiffer, are the steel framed mountian bikes, and bikes designed for panniers like surlys line.

Best of all are longtails, but to carry the range you need, you don't have to go longtail. Just a 26" wheel, strong steel frame will do.

On to the motor, controller, battery setup. It's not that hard to do if you back off the speed some. But you will be carrying an excessivly big battery if you really insist on 50kph. That's very fast for that kind of range. To give an example of what is quite easy to achieve, here is the specs for my commuter.

It's a stock kit from E-BikeKit in the usa. 9 continent motor in 2807- 9x7 winding. On a 48v 15 ah pingbattery, it will go 27 mph top speed. A full discharge at that speed will take me about 20-22 miles depending on hills or wind. To go 31 mph, 50 kph, would take a suprising amount more power. It really skyrockets how much power is used above 20 mph. Your goal of 50kph for 140k would be likely to require 48v 60 ah! That's a full 62 pounds of pingbattery buddy.

So as you see, somethings got to give. Either you build an E motorcycle capable of carrying 48v 60 ah, or at least a longtail cargo bike that can tote 100 pounds, or you simply must make rides that long traveling slower.

At 20 mph, my commuter will go about 30 miles on the 48v 15 ah ping. Two 48v 15 ah pings could take you as far as 100k at 33kph using just about any stock direct drive motor and 20 amp controller. That's not so bad, and with a ride that long, charging some at a long lunch could get you the rest of the way. If you did build it as a longtail, carrying 45 ah would not be impossible to go the whole way.

The one guy who has done close to what you describe wanting to do is Kingfish, So check out this thread.

http://endless-sphere.com/forums/viewtopic.php?t=28573
Part of his solution is to choose lipo batteries, which make the battery carry lighter and physically smaller.

But you require it to be a folder so you can take it on the train? Then you will have to solve the problem in another way. You will need a fast motor so you can reach decent speed in a 20" wheel. Then up the voltage enough to go just a tad faster. I suggest 18s lipo batteries. That's a series connected string of 6s lipo packs. About 75v when fully charged. Then run a 72v 20 amp controller. Carry a reasonable size battery, say 20 ah, and a charger capable of recharging the whole thing in about 1 hour. Ride 30-45 min, charge for an hour, ride 45 min, charge an hour, till you get there. Lots of stops for coffe and a good read.

 

[miuan]

You definitely want the LIghtest POssible batteries to achieve your challenging task.
On my Kona Ute, I can travel 25-30 kms at 45-50kph with 15S 10Ah lipo that weighs 4.5kg. That's minimum 20kg lipo to carry for the distance you need. 10kg on the rack and 10kg in backpack seems to be as much as I'd ever imagine to load on a folding bike, but the fear of bike folding under me would scare the sh!t outta me on a 20 inch folder at 50kph. And I presume you'd like to carry other stuff than batteries too. So, forget either the speed, range OR about the folder, you really really can't have more than two of these.
If you choose 35kph, it'll only require about 13-14kg of lipo but the 120k journey will take 1 hour longer. You can use any geared motor for this speed, and depending on its speed, you can also use any conventional 48V controller.

 

[trietje]

First of all thank you all for your constructive replies!

So i have been rethinking ...
I better rescale my demands to 110 km at 40 km/h (median speed: 33 km/h with traffic and stops?) makes + 3,5 hours of travelling.
Stopping in between is not an option, so i have to reduce my speed and take some longer time over the distance.
LiFePO4 batteries 2 x 48V 15Ah could carry me about 100 km. So 15 kg on the rack and yes, I carry some other things in my backpack
26’’ wheels can be taken on train if foldable, but it seems no option at these speeds and loads to take a foldable bike? Or does it if i reduce the speed and load like in the new concept?
I would like full suspension for comfort and a good sadle to sitt on for + 3,5 hours.
What quality bicycles are available in USA and Europe at reasonable price (folding, strong steel frame, ...)?
What options from engines? Magic Pie (controller in the wheel), Crystalite HS 3540, Nine Continent, …? Geared with conventional 48V controller at these speeds …

 

[trietje]

I also wondered today what the advantage is of a 26'' wheel compard to an 20 '' wheel from a folding bicycle? Electrically or mechanically seen ...

Now with my Dahon folding bicycle and Bafang 36V 250W planet geared motor i consume 7Wh/km driving at 25 km/h.

I wonder what is consumed in Wh/km with 48V battery at 30 kph, 35 kph, 40 kph, 50 kph?

A 48V 15Ah LiPO4 contains 720 Wh, so at 25 km/h that is 100 km drive.
A 48V 20 Ah liPO4 (7,5 kg) contains 960 Wh, so a 125 km drive.

Could two 48V 15Ah packs hold 120 km at 40 kph?

So at 40 kph max speed i can probably get an average of 33 kph.
That is 3,5 hour drive for 115 km. Still an acceptable time without stops in between.

 

[dogman dan]

I just like big wheels because they roll over potholes better. I'm a bit tall, so I often have to put riser bars and long seatposts on every bike to start with. So little folders and bmx bikes don't thrill me. There are frames though, that fit big guys, and have small wheels.

At 25 mph, folder bikes and small wheels won't be a particular hindrance. You won't have to carry as much battery, so now you can perhaps do it on a folder with a strong enough frame. For a bike at at that slower speed, most any direct drive motor will do fine, so chose what you can get easiest in your part of the world. Its when you get above 35 mph, that motors start melting pretty fast.

 

[trietje]

For the moment I am driving my Dahon Cadenza with a Crystalite HS2540 in the front wheel and a battery pack of 36V 15Ah.
With full pack I can drive 35 km at 40 km/h and I pedal moderate

Yesterday, in rainy weather, I had strange motor behaviour.
With strange I mean that the motor does not always respond to the throttle and then after trying a couple of times it does again.
Also the engine just keeps going after releasing the throttle.
After 1 hour of such behaviour the engine stopped and reacted at nothing.
Battery is ok and feeding the controller. All cables checked.

Symptoms are:

when the cable is connect to the engine, the engine gives resistance in driving on human power only. This is even so with battery disconnected. (seems very strange to me).
when cable is disconnected the engine runs freely, without resistance in driving on human power.
e-DR display is working normal, no notification of bad connections or failure.
I can see some vapor/fog of water in display the day after it rained a lot.
Controller LED active and normal function.

What could it be and what could i do to make the engine/setup work again?

Thank you in advance,

Dimitri