E-Bike speed upgrade. Is it possible?

owaishortus

100 µW
Joined
Apr 21, 2018
Messages
9
Well there are plenty of videos and articles on the internet, but I haven't practiced it by myself. Most of them uses the shunt break to increase the speed, but i am confused about it.

I am studying in China and this place is crawling with e-bikes, pretty cheap here. These comes in 24 to 96v (may be more) with different speeds. In smaller bikes (24-60v) speed is the major problem. The circuitry and controllers are almost the same for all. Controllers are very cheap here and its not a bad idea to experiment some. However, there is a button called 'speed increase', if that turned on, the speed might have a 5-10 km/hr increase.

I have just seen one of it (48v), and it was pretty much easier to deal with. I saw a shunt in there but was afraid that the circuit will smoke, because my bike was already going at 45 km/hr. The speed controller button and various other wires were disconnected (by a service person), due to that I had no speed issue.

But i am planning to get another used e-bike and do some experiments with that. Could you people kindly share your experiences with speed upgrades
 
You're in China, get a controller as big as you want and same with the hub motor. You can do over 100 kph easily with a QS205. No need to mess with small crap.
 
More amps, the shunt, increases power, but it never changes the max rpm of the motor without load. Speed might increase when you increase amps simply because the load on the motor in wind resistance requires more power. For example, 500w won't go much faster than 30 kph. So without changing volts, you might get some speed increase with more amps. But never more than that motors max rpm by voltage. More power does get you to that speed quicker, which is always good.


But all motors spin faster with more volts. Higher volts, higher max rpm from the same motor. The way to get a big increase in speed from a given motor, is a new controller with more volts. This requires of course, a battery with matching, higher volts. While you are at it, get more amps too in the new controller. Like replace a 48v 20 amps controller (1000w) with a 60v 30 amps. (1800w) Higher speed, AND get to speed fast. :mrgreen:

Controllers are not expensive, but the battery voltage increase can be, simply because your old 48v charger is useless on a 60v battery.

Worth it, youbectha.
 
I just got an e-scooter from scrap, so i want to upgrade it. I can increase the voltage from 48v to 60v, which will be more than enough for me. I can replace the controller and charger as they are cheap. But I don't know about the voltage capacity of the motor. Their is a code written on the rear wheel, but I don' t understand what is the wattage.. There is written 48v but the wattage is confusing... Because my friend is using 60v 20A battery with a bike whose motor is 48v 800w. I tried to upload the images here but there is some problem with the website
 
BTW i know to calculate the watts if i have voltage and amps. I will change the controller and charger for sure, but what about the maximum voltage a motor can take? Is there any formula or something like that to calculate it?
 
Motor voltage limits are not much of a problem. They are ok until the insulation breaks down, which won't occur until quite high voltage.

When you increase voltage the current increases and this can increase heat in the motor as well as the controller. 48 to 60 is not a big change. Monitor the temperatures and try it.

Higher speeds do increase risk of injury significantly, be careful and wear protective equipment. Do your testing in a safe place.
 
I have decided to upgrade my e-bike. Currently a 1500 watt MAC motor with 12fet infineon controller running off a 48v 26.1AH battery (high output). I have put only 100 miles on it. I can get it to 30mph. But 35-38mph would be safer for traffic flow.
I am thinking of getting a MXUS 3000 3T hub with an upgraded controller to increase the amps from on my current controller to 65-70.
Do i need to get a higher voltage battery too??
I am not looking for immense speed increase but some would be helpful for hills and pulling out of intersections and flowing with traffic. (This is a daily driver on nice days ) 3-6 miles per day to my office.
 
changeissimple said:
I have decided to upgrade my e-bike. Currently a 1500 watt MAC motor with 12fet infineon controller running off a 48v 26.1AH battery (high output). I have put only 100 miles on it. I can get it to 30mph. But 35-38mph would be safer for traffic flow.
I am thinking of getting a MXUS 3000 3T hub with an upgraded controller to increase the amps from on my current controller to 65-70.
Do i need to get a higher voltage battery too??
I am not looking for immense speed increase but some would be helpful for hills and pulling out of intersections and flowing with traffic. (This is a daily driver on nice days ) 3-6 miles per day to my office.

Well with this much high power motor (1500w) the speed will definetly increase, I think you just need to add up another 12v 26.1Ah battery in series with the same voltage and higher power controller.. But kindly ask the opinion of some expert first, bcz m just a newbie.. All the best
 
I checked the controller, it was 450w, so i thought to give it a go, and worked like a pro.. First I tested it with original 48v 12Ah while the bike was on double stand. Then tested it with 60v 12Ah, speed was almost double with the bike whumping. It was for a few minutes, and I checked the motor, controller and wires temperature, nothing was hot.. I didn't test it on road, bcz the 60v battery setup I made was from a 48v lithium and 12v lead-acid, so I was afraid of battery explosion.. Though it worked well for few minutes.. I checked the lighting, that was fine, but the horn wasn't giving good sound. So the test was clear. 
During the test on double stand, it was alright. However, before the test, there was a glitch in this bike. Whenever I increase the speed (pull accelerator to the fullest) the bike shuts off, and then after removing the battery socket off and then back on, it resets [this problem was also told by the person who sold this bike]. I thought the wiring might be a problem, for that I solidified all the connections, but again on the road it shuts off with maximum accelerator. I am so confused whether this problem is in the controller, motor, battery or accelerator. 
 
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