Can you identify this motor?

[romandesign]

My new inexpensive fat tire ebike came with this motor. I'm curious what it is. It's either a brand I don't know or a white-label drive from a known brand. I couldn't locate that logo and there is no other branding on it. The other side has a long oval depression with an arrow inside it, but no brand. The oval looks similar to a BAFANG motor, where the brand is usually located, but it has a long arrow instead. There is no other small depression with an arrow that BAFANG motors usually have, and the other side looks like this:


It does look similar to one of the BAFANG models that are listed on different websites, though their website doesn't show that kind of notching on the newer models.

Any ideas?

 

[jetpackjbd]

Typically, cheap eBikes use no-name motors from whatever warehouse in China is willing to sell them for the cheapest. Looking up the model number doesn’t yield any results, someone else on the forum might be able to identify it but it’s like unbranded. If you plan to replace it in the future, ebike motors are usually universal as long as they have the same specs, form factor, and connector.

 

[eee291]

A mxus maybe?

MXUS GDR-15FAT - Google Search

 

[romandesign]

A mxus maybe?

MXUS GDR-15FAT - Google Search

Hmm, thanks, it matches closer than BAFANG. The 3 pics on their product page do not match each other, but 2 of them are an exact match.

This one is almost an exact match, though I don't have branding on the rectangular depression, the shape matches and the screw color etc. (the end nuts don't match though)

- This matches exactly

- the arrow is exactly like mine, but the screws are black, so it's the same view as the first one but doesn't match exacly as the screws are different color. Maybe the first one is a rendering and this one is real.

There's even a graph, which would be nice if I could make any sense of it:

 

[eee291]

Just look at the right side of the picture, it has all the important info summarized, peak efficiency, max output and torque.

 

[romandesign]

Just look at the right side of the picture, it has all the important info summarized, peak efficiency, max output and torque.

OK, that's a start. What conclusions could I make from this?

When suspended in the air the display shows around 0.8A to 1A draw at full power. Speed limiter is disabled, speed shows 49km/h, full battery charge. By hearing the variations in sound I estimate RPMs to be about 360 (I can hear ~6 revolutions per second). I guess it's close to "unload" parameter, considering 52V fresh charge.

So any conclusions I can make from the chart? What would be the most efficient speed? I guess I could aim for 21.15A load on the road and see what speed it gets me to, and that would be most efficient. Am I correct? Though there's drag etc. involved of course...

Update:
Hmm, I checked my S830 settings and "current draw limit" is set to 12A from the factory (14.5Ah 48V battery). Does it make sense? I don't think I should increase it if that's the safe limit. Then I'm not sure what the most efficient mode is...

 

[romandesign]

Hmm, now that's interesting! I opened the controller cover and looked at my controller model. So if I understand it correctly:
1. my motor can draw 24.5A on max power, and it's 21.31A t max torque.
2. My Controller is rated for 18A
3. But my S830 current limiter is set for 12A!!!

That raises the question: should I increase my current limiter, or just leave it and play on the safe side? Is 12A limit normal for inexpensive 500W hub systems?



My battery supports 25A discharge...

 

[eee291]

You need to know the discharge current rating of the battery and BMS before you increase it.
I drew some lines, I hope this will make it more clear.
BTW efficiency is based on motor rpm, so if you stay between 190 and 280 rpm, it will be 80+ percent efficient regardless of current.

 

[amberwolf]

When suspended in the air the display shows around 0.8A to 1A draw at full power. Speed limiter is disabled, speed shows 49km/h, full battery charge. By hearing the variations in sound I estimate RPMs to be about 360 (I can hear ~6 revolutions per second). I guess it's close to "unload" parameter, considering 52V fresh charge.

Loaded RPM is usualy around 80% of the unloaded, given sufficient power to maintain the speed under the given conditions.

So any conclusions I can make from the chart? What would be the most efficient speed? I guess I could aim for 21.15A load on the road and see what speed it gets me to, and that would be most efficient. Am I correct? Though there's drag etc. involved of course...

Update:
Hmm, I checked my S830 settings and "current draw limit" is set to 12A from the factory (14.5Ah 48V battery). Does it make sense? I don't think I should increase it if that's the safe limit. Then I'm not sure what the most efficient mode is...

Do you have a wattmeter you can use to measure actual power / current from the battery? (a multimeter typically only goes up to about 10A, unless you have a clamp-on type).

What is your battery's rating, it's max continuous current delivery ability? (usually less than the peak current).

 

[romandesign]

I drew some lines, I hope this will make it more clear.

Fantastic, thanks!

BTW efficiency is based on motor rpm, so if you stay between 190 and 280 rpm, it will be 80+ percent efficient regardless of current.

That should translate to speeds of ~26 to ~39 km/h, which is good to know!

Do you have a wattmeter you can use to measure actual power / current from the battery? (a multimeter typically only goes up to about 10A, unless you have a clamp-on type).

No, just the multimeter. Also, the connectors are heat-shrink-wrapped so I don't want to disconnect them.

What is your battery's rating, it's max continuous current delivery ability? (usually less than the peak current).

All I know is what the label says, but I think 25A max current should deliver >16A constant, shouldn't it?

Loaded RPM is usualy around 80% of the unloaded, given sufficient power to maintain the speed under the given conditions.

That should give me ~256 RPM or 35.5 km/h I guess, but I already went faster at ~37kph and it felt like it could go faster, but I chickened out

 

[romandesign]

What is your battery's rating, it's max continuous current delivery ability? (usually less than the peak current).

Ah, that may be the limiting factor. I googled and it seems that most similar batteries have a continuous discharge current that is roughly half of the peak discharge current. So for my 25A max battery it would be ~12.5A, which would make my battery the limiting factor. That also matches the 12A current limiter settings. Then it makes sense.