Am I asking too much?

poeli · Apr 12, 2015

Hi all,

I currently have a foldable electrid pedelec. The motor is180W and the battery 36V 12 Ah. This is the frame and bike:
https://www.matrabike.be/product/1418/silent-force-sf-201

Now i bought this bike to commute, but since i changed jobs i wanna use it for another reason. I have to do a distance of around 40kms, but want to make this bike (or make a complete new one) faster. Now the speed is limited to 25kph, but being able to increase it to 30-35 kph would be nice (and really reduce the travel time).
Now my question. What do i need? I know how to 'hack' the controller (i was able to display higher speeds, but i guess the current was limited by the controller). Do i need a 48V battery to increase my speed or an all complete controller? Or can i modify the shunt resistor and make it go faster? 180W is not much, i don't know what the possibilities are?

Kind regards, and thanks for the support.

dogman dan · Apr 12, 2015

Likely you need a new controller to run 48v, have more current, and have the controller last awhile.

But not too much, that motor can't handle a 48v 40 amps controller. You might get away with 700-1000w for awhile, like a 20 amps 48v controller. Best approach might be new everything, like a 1000w rear motor kit. And put it on another bike, so you'd have two bikes, possibly selling off the folder.

Drunkskunk · Apr 12, 2015

More speed needs more voltage. Motors have a rated RPM per volt, which is called it's KV. So giving it more voltage means getting more RPM, and therefor more speed. That is, if it's also getting enough amps.

Unfortunately, a 180w motor is going to be struggling to move a person, and trying to get much more speed out of it may cause it to burn up. A 48 volt battery is expensive, and it may cause the motor to burn up. Is that a risk you are willing to accept?

35kph is pretty easy for a 350w to 500w motor and controller to do without even trying hard, and many will do that at 36 volts. That battery you have may not be able to stand up to the amp load of the bigger motors, but it might be cheaper to replace the motor to test the battery, then it would be to replace the battery to test the motor. Worst case, you burn up everything. Best case, it works just fine, you get the speed you want, and you only had to replace the cheaper motor and controller.

d8veh · Apr 13, 2015

You'll need a 48v battery and controller. It would probably be better to sell it and convert a standard bike.

I doubt that there's anything you can do to your present controller to get significantly more speed. Soldering the shunt gives better hill-climbing, but not more speed. You might be able to get a bit more speed by derestricting it. Is there an LCD. If not, look for two white wires joined in a loop coming out of the controller. Disconnect them.

poeli · Apr 18, 2015

Thanks for all the answers. If i consider building a bike from scratch (so selling the one i have now), how much would cost me this? Let's say, that if I'm building from scratch a speed of 40kmh is a requirement, so it takes me one hour to get to where i need to get (all flat road).
I'm thinking of buying a small motorcycle which goes 80kmh, but if an electric bike is cheaper (no insurance, fuel, maintenance, ect), I'd opt for that of course, as it's also more fun. I had a look at the falcon electric bikes, are these any good, as i can't find any review of them?

d8veh · Apr 18, 2015

An electric bicycle that can sustain 40km/h will cost more than a motorcycle. When we talk about maximum speeds, we normally mean on the flat. You can build a 1000w bike that can reach about 50 km/h, but they soon slow down on hills. A 50cc motorcycle can maintain 50km/h nearly all the time.

poeli · Apr 18, 2015

Well The netherlands are pretty flat so no hills here (or max a bridge or something). Will research this further.
Thanks anyways!

dogman dan · Apr 20, 2015

The 40 kph cruise is not hard to achieve, nearly any kind of hub motor kit that runs on 48v will do that easily. Likely have a bit more speed at the start of the ride, but still have 40 kph (25 mph) in it even at the very end.

The power this is likely to take is 35 watt hours per mile. For 25 miles. Let's call it 30 miles, so you have some reserve. On a windy day it will take more than 35 wh/mi to go 25 mph. Sorry for the miles, but I just think in USA. In the end the result, what you need is the same.

So, 35 wh/mi for 30 miles. 35 x30. You will need about 900wh. Get a 48v 20 ah battery, and you will have about 1000 wh. ( 48 x 20 =960.

Prices in your country, I have no idea. taxes, duties etc. But what you need is a 48v motor kit, and a 48v 20 ah battery. Or two 48v 10 ah, whatever adds up to it.

A little bit slower, cruising closer to 20 mph/ 32-35 kph is a lot more efficient. At that speed, you only need 48v 15 ah.

What you want to do, speed and distance is easy as pie for a more powerful ebike. It just needs to be a big enough bike to comfortably ride that fast for that distance. Start with a 26" bike that fits your body very well.

poeli · Apr 23, 2015

dogman dan said:
The 40 kph cruise is not hard to achieve, nearly any kind of hub motor kit that runs on 48v will do that easily. Likely have a bit more speed at the start of the ride, but still have 40 kph (25 mph) in it even at the very end.

The power this is likely to take is 35 watt hours per mile. For 25 miles. Let's call it 30 miles, so you have some reserve. On a windy day it will take more than 35 wh/mi to go 25 mph. Sorry for the miles, but I just think in USA. In the end the result, what you need is the same.

So, 35 wh/mi for 30 miles. 35 x30. You will need about 900wh. Get a 48v 20 ah battery, and you will have about 1000 wh. ( 48 x 20 =960.

Prices in your country, I have no idea. taxes, duties etc. But what you need is a 48v motor kit, and a 48v 20 ah battery. Or two 48v 10 ah, whatever adds up to it.

A little bit slower, cruising closer to 20 mph/ 32-35 kph is a lot more efficient. At that speed, you only need 48v 15 ah.

What you want to do, speed and distance is easy as pie for a more powerful ebike. It just needs to be a big enough bike to comfortably ride that fast for that distance. Start with a 26" bike that fits your body very well.

Thank you so much, this is a really great starting point to start looking for a kit/battery!

Am I asking too much?

poeli

10 mW

dogman dan

1 PW

Drunkskunk

100 GW

d8veh

1 GW

poeli

10 mW

d8veh

1 GW

poeli

10 mW

dogman dan

1 PW

poeli

10 mW

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