Upgrade from 250W to 500W

[Thomasg]

Good evening

I have a Long John e-bike with a standard 250W 36V brushless front wheel engine. I want to increase the speed and torque for a smoother ride.

I’m a bit new to e-bike builds. Are there any easy ways to delimit the engine or retrofit a 500W engine without having to replace all original components?

Thanks in advance.

 

[E-HP]

What are the specs for your battery? Can you post a pic of the label on the controller?

 

[Thomasg]

It’s one of these Hailong battery controllers. Currently, I have 1x 9ah and 1x 10.4ah 36v batteries

 

[fill]

Generally ebikes/kits sold within the EU will have hobbled firmware, locking out some if not all configurable settings as to conform wiith regulations. some systems can be reflashed with international f/w but thats a procedure.. and the general solution is to replace the controller/display with something from the Ketung (KT) range, These are popular as they have a wide range of displays that can be used and have a full set of configurable parameters, some may say too many, but manuals in chenglish exist for download..

If for example your bike is fitted with a 15a (peak current) controller now, a new 17a or 20a controller will allow you to provide more power to your existing motor since Volts X Amps = Watts.. with a 20a controller.. if your batteries can provide that drain could give you upto
20 x 42=840W of power to give your motor.. Of course continual running at that level could overheat the motor, but when needed to get up a hill

edit the max drain of a battery will be a 3rd metric measured in Amps not to be confused with Ah amphours the metric for battery storage capacity

 

[E-HP]

It’s one of these Hailong battery controllers. Currently, I have 1x 9ah and 1x 10.4ah 36v batteries

Is there any label on the battery that states how much current output the battery can provide? In general, on factory bikes, the battery is sized just large enough to support the other components (motor, controller), but good quality factory bikes use quality name brand cells (LG, Sanyo, Samsung, Sony, etc.) that may support an upgrade, in your case from 250W to 500W (requiring double the current).
Still, more power doesn't equate to more speed, since the speed of an electric motor is determined by voltage. Power may increase speed if the stock speed is over 20-25 mph, since above those speeds, wind resistance plays a factor. I don't think going from 250W to 500W will make much difference in speed in your case.
You didn't provide the controller label. Some 36V controllers can support 48V depending on the internal components. Going to 48V will make the bike 1/3 faster (48/36 = 1.33333). In that case, you wouldn't be changing the motor, but changing the battery.