Top speed for 24v 350watts

[lokojones]

Hi there
I have got rear 350w brush-less motor with 24v 15ah LiFePO4 battery. For now my top speed is 25km(16miles) and not let me go faster (to go faster need to stop use motor). Tested bike upside down and the maximum speed is 25km (easy to quest). I used the bike for daily commuting, around 12miles and battery voltages after that drop just from 26.2 to 26v so i have still some juice there to used (that's my theory)

Question: is any change to speed up the rpm to let the bike go faster (motor bought as the kit from Chine) by updating controller? or throttle?

is any chance to give more power with the same set? by changing controller?

my weight is 75kg

many thanks or any suggestion.

Regards

 

[FMB42]

Welcome to ES lokojones.

You can easily increase your top speed by reducing aerodynamic drag. This can be achieved by lowering your handlebar and/or seat height or by adding a simple fairing (a good fairing can increase your top speed by as much as 2mph @ ~ 20mph). You can also increase your tire pressure for a general reduction in drag (just make sure that you don't exceed the factory recommended tire pressure). Increasing the tire (diameter) size can, of course, be another means increasing top speed (this will, at best, only result in an increase in top speed of ~0.5 mph).

There are a number of other electro/mechnical improvements that can increase your top speed. However, you should first determine the following:

1. The maximum voltage rating or ratings of your controller.

2. The continuous and maximum current ratings of your controller.

Note: increasing system current will generally result in an increase in torque while, an increase in voltage will generally result in an increase in top speed.


Once you know the above specifications you can consider upgrading your battery to 36 volts. This may (or may not) require an upgraded controller that can handle the increased voltage and possible current increase. This is, btw, one of the more common means of increasing top speeds (note: you'd probably see a 1.5-2.5 mph increase by upgrading to 36v). You will, of course, need to upgrade your battery charger as well.

Just make sure that the voltage and current ratings of your existing (or replacement controller) and upgraded battery are evenly matched.

 

[oldpiper]

Of course, one no-cost way to increase your speed (which I personally use only as a last resort, in an emergency situation) is to pedal like he**. But, I guess if I did it frequently, I could get back down to 75 kg, myself :wink: .

Cameron

 

[lokojones]

thanks for the response.

but what about the RPM - when the bike i upside down - nothing should stop the wheel, but the speed is just 25km - in real scenario cant go faster (motor with pedaling), because the limited rpm slow me down. have to stop use the engine, after that can pedaling over this limit

when trying pedaling over 25km/h with full throttle I feel like I'm driving up the hill. need to come back to 25km to feel like I'm driving down the hill

what about Cruise Speed Controller, looks like this one is Programmable and can change the rpm?

http://www.goldenmotor.com/e-Bike-DIY/PI-200%20GUI.jpg

my goal is go faster than 25km with pedaling - cant do it right now.

regards

 

[dumbass]

I had (have) 2 Cyclone 360w 24v motor kits on a set of Mt bikes with a 6 speed rear hub. The motor drives through the crain chain and therefore, uses the bikes gearing. With peddle assist I was able to do 22MPH. I started out using SLA batteries 24v 18ah. I later upgraded to lifepo4 24v 20ah packs. The speed really didn't improve but the distance did. And BTW I did that sitting full upright and I weighed 215# and the bike was 75# with 2 packs on it.

You don't mention the speed of the motor but based on the fact that your getting the same speed while riding and with the bike up side down this sounds a little strange. A 25% load loss is very common. So assuming that your numbers are correct it sounds like you should be able to re-gear between the motor output and the read wheel. How does the motor drive the rear wheel independantly or through the crank chain or ? One other thing we need to know is what size is your controller. I think I had a 35a controller on mine. This will make a big difference in power (RPM) output.

Bob

 

[FMB42]

You don't mention the speed of the motor but based on the fact that your getting the same speed while riding and with the bike up side down this sounds a little strange. Bob

This is a good point. I'm wondering if there isn't a "speed limiting" circuit on this system...If so, maybe this "speed limiting" circuit can be disabled by removing a "wire jumper" (if equipped) from a "speed limiting" circuit wiring pig tail?

I'd go over the owner's manual again while looking for any reference on a possible "speed limiting" circuit and how to disable it. Some systems have a 2 wire "pig tail" exiting from the controller/wiring harness that has a small connector plugged into the end of pig tail that is used to "close" the speed limiter circuit (which,in turn, enables the speed limit to a predetermined speed).

 

[lokojones]

thats it that could be a reason - maybe i have speed limiting on the system. thanks

 

[FMB42]

BTW lokojones, your top speed of 25km sounds pretty decent for a 24v 350w setup. However, it should (as Bob noticed) produce a noticeably higher top speed while unloaded (upside down)...

HTH.