Help identify old 8fun hub motor (bfswx02-p)

[olkaped]

Sorry if i post in wrong tread, first time poster, long time lurker

I have a fatbike 36v 250w 8fun rear hub motor, from around 2012-2015, bought it of a friend that used it for some months before he broke something and it had collected dust for many years, so motor is in very good condition

I am struggeling to find the exact model, i want to push it to the safest max limit and there are so many different models im lost.

Any help or advice appreciated

My plan is to unrestrict the speed limit, and im afraid to over pressure the motor. When i throttle up to 25/30kmt i feel it just dont want to use more power, im using a controller without display, and i plan to connect my spare controller that has display to unlock the restriction via an unrestricted controller and display. Or change the wheel size to trick it to give me power above 25kmt

 

[amberwolf]

Doesn't really matter what model it is for how much power it can handle; you won't find any charts that specify this, as it depends on your riding conditions, usage, environment/heat, etc.

I recommend experimenting with the ebikes.ca motor simulator to see how these things work, and then poking around at the many threads discussing motor heating/cooling, and the ones discussing geared hubmotors of all kinds, especially gear and clutch failures of various types. Those will help you see the limitations and potential weak points of your motor/etc, so you can try to judge or guess where their real limits are.

 

[olkaped]

Doesn't really matter what model it is for how much power it can handle; you won't find any charts that specify this, as it depends on your riding conditions, usage, environment/heat, etc.

I recommend experimenting with the ebikes.ca motor simulator to see how these things work, and then poking around at the many threads discussing motor heating/cooling, and the ones discussing geared hubmotors of all kinds, especially gear and clutch failures of various types. Those will help you see the limitations and potential weak points of your motor/etc, so you can try to judge or guess where their real limits are.

Thanks for replaying, ill keep that in mind im not too worried now that ive looked over all my components and compered to similar hub motors, my controller is limiting to 13ah, so if i over tune it wont hurt my motor cuz it wont go over 13ah cuz the controller wont take more than 13 ah witch is fine in my case

I have one more question, i wanted to make it a 2wheel drive, is it super important to have same spec motors? I want to use 2controllers and 2sepperate batteries so i can turn off front wheel drive whenever i want. I dont see problem to have one bigger motor then the other, but im unsure, alot of different opinions on this topic

And thanks again for taking time to answar my questions amberwolf, i respekt you alot bcuz of all the help you provide in this forum, your comments have helped me alot in many different treads

 

[amberwolf]

Thanks for replaying, ill keep that in mind im not too worried now that ive looked over all my components and compered to similar hub motors, my controller is limiting to 13ah, so if i over tune it wont hurt my motor cuz it wont go over 13ah cuz the controller wont take more than 13 ah witch is fine in my case

Keep in mind that Ah (amp-hours) is a capacity, not a current, and is only applicable to a battery, not a controller, motor, etc.

A (amps) is a current, and is completely different than Ah, and neither can be used in place of the other.

So you should look at your system's information and specs again, to be sure you have the right numbers and units. It's pretty important, because if you're using numbers that mean one thing from one part of the system in place of numbers that mean a completely different thing, you're not going to get the results you expect, and can damage parts of your system if the mismatch is sufficient.

I have one more question, i wanted to make it a 2wheel drive, is it super important to have same spec motors? I want to use 2controllers and 2sepperate batteries so i can turn off front wheel drive whenever i want. I dont see problem to have one bigger motor then the other, but im unsure, alot of different opinions on this topic

That entirely depends on what you expect from the system and how you will use it. I recommend using the ebikes.ca motor simulator in 2WD mode to see how variations on each wheel's systems will work for you in your specific riding conditions and style, etc.

There are a lot of discussions about 2WD or AWD that will help, too, but it will be a fair bit of reading.

And thanks again for taking time to answar my questions amberwolf, i respekt you alot bcuz of all the help you provide in this forum, your comments have helped me alot in many different treads

You're welcome, but I only see this thread by you?

 

[Chalo]

For 2WD, it's best if the motors are trying to reach the same unloaded speed or very similar. They don't need to match in any other way.

For good vehicle dynamics, it's better for the more powerful motor to be in the rear wheel, but that isn't critical.

 

[olkaped]

For 2WD, it's best if the motors are trying to reach the same unloaded speed or very similar. They don't need to match in any other way.

For good vehicle dynamics, it's better for the more powerful motor to be in the rear wheel, but that isn't critical.

Thanks for clarifying it, im a person that always want to be 100% sure before doing something

 

[olkaped]

Keep in mind that Ah (amp-hours) is a capacity, not a current, and is only applicable to a battery, not a controller, motor, etc.

A (amps) is a current, and is completely different than Ah, and neither can be used in place of the other.

So you should look at your system's information and specs again, to be sure you have the right numbers and units. It's pretty important, because if you're using numbers that mean one thing from one part of the system in place of numbers that mean a completely different thing, you're not going to get the results you expect, and can damage parts of your system if the mismatch is sufficient.




That entirely depends on what you expect from the system and how you will use it. I recommend using the ebikes.ca motor simulator in 2WD mode to see how variations on each wheel's systems will work for you in your specific riding conditions and style, etc.

There are a lot of discussions about 2WD or AWD that will help, too, but it will be a fair bit of reading.



You're welcome, but I only see this thread by you?

Im a first time poster on endless-sphere, but past year, maybe 2 have always come here for answars about ebike related questions, ive gone trought alot of KT controllers and brainpower ones, and when i get stuck and dont se a way to solve my problem. So when i have read couple times your solutions i get some ideas how to solve my own problem

And the alias amberwolf has gotten funny in my eyes, on the ground that i see your help comment very often haha

And yeah i wrote wrong, ah and a is two completly different things, i meant that my controller has a 13a limit. Not AH haha, i have a 15ah battery, and if i multiply it by volt i get my wattage. So 36v times 13 is 468w, and im almost 100% sure that my motor will handle it.

But i have ofc written down your suggestions, ill keep my eye on overheating to be carefull not to damage anything, and if anything wierd is happening with motor like jerkyness etc

 

[AGS]

Your Bafang SWX02 is a 13T wind. It’s not a fast motor but good for hill climbing. I’m running an SWX02 at over 1500 watts oil cooled with a 35 amp controller.

Your 13 amp controller will not overheat that motor under normal riding conditions.

 

[olkaped]

Your Bafang SWX02 is a 13T wind. It’s not a fast motor but good for hill climbing. I’m running an SWX02 at over 1500 watts oil cooled with a 35 amp controller.

Your 13 amp controller will not overheat that motor under normal riding conditions.

Thanks so much i was thinking of opening the motor to find some more information, model number or something. But after googling swx02 i see my motor

Omg 1500w? On that motor? Does it get rlly noisy when peak wattage? Or is it managable?

 

[AGS]

I have fitted a temperature sensor inside the motor and with the oil (ATF) it doesn’t get above 90C flat out for extended periods.

I think 35 amps is as far as you can push it because it’s at the limit for the motor cable and connector.

Without oil it would get to 150C in a few minutes and the windings would burn out, the magnets would be ruined and the gears would melt.

The trick is to keep the oil inside the motor so it doesn’t leak out all over the brake disc. I get a bit of leaching into the cable connector through the wires, but not through the axle or cover plate because I have used loctite flange sealant on these parts.

It isn’t noisy. I’m still using the nylon gears and they have held up for nearly 900 miles.

Range suffers because I only have a 52 Volt 40 Amp 20AH battery, so it’s only good for around 20 miles at full speed.

Ive started riding at level 3 PAS and go a bit slower these days to preserve the battery. But it’s nice to have the additional performance if I’m in a hurry.

Mine is a 10T wind, so a bit more top speed and less acceleration than yours.

Wheel diameter is important on hub motors because that affects the gearing. I’m running it on 26” wheels and 3” tyres, and my overall wheel diameter is around 29”. So my top speed is around 30mph.

I use this bike mainly for short 2 mile journeys either twice or four times a day along a main road with no hills and I want to make the journey quickly, so it’s ideal for my application.

You don’t need 2WD unless you are doing serious offroading and need the grip on both front and rear. It just overcomplicates the bike and makes it heavier. And you need a huge battery with two controllers if you are going to run two motors simultaneously.

And importantly you should not run a front hub if you have suspension forks because they will lock up and give you a horrible ride.

Also if you are going to upgrade your controller you must fit torque arms to the motor otherwise it will twist out of the dropouts and ruin both the motor and your frame.