Help! New to ebikes need someguidance on upgrades

[steverebo]

So I've just got a dawes falcon folding ebike it has a mxus xf08 250w36v20" hub can I increase the speed of this motor and if so what should I buy

 

[saneagle]

So I've just got a dawes falcon folding ebike it has a mxus xf08 250w36v20" hub can I increase the speed of this motor and if so what should I buy

Show pictures of the whole bike and the control panel.

 

[steverebo]

Here are some pictures

 

[AGS]

You can increase the top speed a bit by replacing the battery, controller and display with a 48v or 52v. But the small wheel size will always be working against you. And for any significant improvement you will have to oil cool the motor, or it will overheat.

Financially it’s not really worth upgrading to that extent because that’s another £500 on top of what you have already paid for the bike and I think you will be disappointed with the performance improvement.

 

[steverebo]

I can grab a new 48v controller and lcd from aliexpress for cheap what kind of performance would I get. I'm not looking at getting mad speed but instead I want the assistance to stop dropping out all the time especially when I'm not really going that fast it seems to stops and start

 

[saneagle]

Here are some pictures

Your photo isn't clear, but it looks like you have the white speed restriction wires. if they're two single wires connected in a loop, disconnect them to release the speed limit.

If you're successful in releasing the software speed limit, the top speed will still be limited by the motor design and the current from the controller. 12 amps is very low, and not enough power to go much past 15 mph on the flat. The motor has a top speed related to the number of turns in the coils inside it. You can't change that. I'm going to guess that it will max out at around 19 mph, but the power will ramp down from 15 mph, so it'll only achieve that downhill.

If you want actual 20 mph riding, you'd need to change the battery and controller to 48v, but then your brakes might not be good enough. When I ran my 20" wheeled Dahon with 48v at that speed, the brakes wore out extremely quickly. If you're not too heavy, that might be OK, but not if you're say 90kg or more. 48v will give you approximately 30% increase in power, torque and speed. You can also go up to 15 amps, which will increase power and torque by another 25%.

I disagree with the above post. Oil cooling wouldn't be needed. I've run many 36v motors at 48v and only one showed signs of getting warmer tha normal, but it was already a fast winding and it had weak magnets or insufficient amount of copper in the windings. All the others didn't seem to get any warmer than when at 36v.

A decent 48v controller and LCD is about £80. A 48v battery can be had for about £200.

Your 36v battery can probably give a bit more power. You can increase the current from the controller to say around 16A by adjusting the shunt value inside it by adding a bit of solder. If you add a big blob of solder to 25% of its length, you'll get approximately 25% more power and torque, so it'll accelerate faster and hold a higher top speed at the cost of the battery going down quicker. Alternatively, you can buy a 15A controller with LCD from about £40. You shouln't go much more than that because your battery might not be able to provide that much current, so will start cutting out. 15A should easily be alright and a good channce of 17 amps, then cut-outs become increasingly more probable.

Your control system is not very good. If you increase the power, it'll make the start-up a bit jerky because on each od the three levels, you get the same maximum power but with different maximum speeds. That's where the £80 controller is a lot better. It's power algorithms are much more user-friendly. None of that matters when you only have low power, but it becomes more important when you increase the power.

 

[steverebo]

Thank you could you recommend a controller and lcd?

Also my bike has a rear rack battery can I just replace the slide in battery with a 48v one or do I need to replace the lot

 

[thelarkbox]

in order to get more speed you need to 1)remove the limit set, and 2 provide more power to the motor.

since power in watts is derived from voltage and amps supplied increasing either will increase power output.

so to overcome the speed limit an alternative more configurable controller and headset combo is required,

a more configurable controller that can use 48v too and provide more amps will also increase power output.

A KT controller/headset combo is popular and afaik the sine wave versions are generally preferred, the headset options are numerous, but to access the config settings stick to the lcd 3 button options.

Be mindful your current sensors , wheel, and throttle? are connected to the controller with what i understand to be Higo connectors, so do not buy the controller with the julet'waterproof' connectors unless you want to replace all the sensors etc too.

Sorry i dont have a link to a controller im looking for 1 myself atm..
circa £40-70+ depending on how long your prepared to wait..

there are controller headset options that cost significantly less than a KT sinewave 48/36v hi power controller but are less than in many important respects.

 

[AGS]

I had to oil cool my SWX02 running at 52 volts with a 35 amp controller. The grin simulator was spot on with the time to overheat, I tested it without oil and I stopped the motor at 120c.

I have fitted a LM35 temperature sensor and I’m monitoring the temp using a 3 1/2 digit 2 volt meter. I also set up an alarm at 100c and a trip at 110c using a couple of voltage comparators that trigger relays in case I’m not paying attention to the temperature gauge. But with 60ml of ATF I haven’t seen the temperature rise above 90c, so in my case oil cooling was very effective.

You can’t tell the temperature inside of the motor by just touching the case especially with an inrunner.

Youtube is full up with videos showing overheated motors where the owners have decided to run them at higher power, then wonder why the windings have all burned out and the nylon gears have melted.

 

[Nealh]

Oil cooling not needed for 48v < 20a.
Opting for anything more the yes oil cooling is needed as one is trying to put 2kw thru a 250w hub, Horses for courses.

 

[saneagle]

I had to oil cool my SWX02 running at 52 volts with a 35 amp controller. The grin simulator was spot on with the time to overheat. I have fitted a LM35 temperature sensor and gauge, also an alarm set to 100c and a trip set to 110c in case I’m not paying attention to the temperature gauge. But with 60ml of ATF I haven’t seen the temperature rise above 90c, so in my case oil cooling was very effective.

You can’t tell the temperature inside of the motor by just touching the case especially with an inrunner.

Youtube is full up with videos showing overheated motors where the owners have decided to run them at higher power, then wonder why the windings have all burned out.

I don't think OP is going to be running his 20" wheeled rim braked folding bike at nearly 2kW, otherwise his bike might start folding when he doesn't want it too.

 

[AGS]

He should still make sure he has a couple of decent torque arms even at 48 volts and 20 amps.

 

[steverebo]

Thank you guys for all your help, I have ordered a sine wave controller that cab do 36v and 48v with lcd. Is 17A OK for a 36v battery and 250w motor?

 

[saneagle]

Thank you guys for all your help, I have ordered a sine wave controller that cab do 36v and 48v with lcd. Is 17A OK for a 36v battery and 250w motor?

That should be fine. Most batteries can manage 17A unless it's a particularly small battery, like 5AH. If your battery can't provide that much current, you'll see the voltage sagging badly on the LCD , and/or it'll cut off. In that case you can solve it by reducing the max current in the settings, shaving the the shunt or only using up to level 4 instead of 5.