Identifying hub motor specs?

Joined
Feb 10, 2022
Messages
91
Location
Norfolk UK


I wonder if anyone here can help? I have a number of hub motors and all are said to be about 250W with maybe 1 or 2 350W, So far I have only managed the time to get one installed on Joan's sit-up-and-beg trike. Soon I'd like to put one on my delta. The one in the pic looks to be unused or at least in great condition and is in a nice wheel- ideal. Only problem is it has no markings to say what voltage it is. In fact there are no markings at all apart from the '8FUN' name. Looking up info on the 8FUN it seems they come in both 24v and 36v flavours so not much help there. Other motors in the collection that are not marked with voltage seem to have either a 24 or a 36 in their serial numbers which suggests the voltage but this one has no serial number?

I imagine if I try it at 24v it may seem a bit lazy if it's actually 36v but not sure. Is there a way to determine the voltage at all? Measuring resistance between phase wire maybe? Would there be a big difference?

Any help gratefully received.
Thanks
John
 
Joined
Jan 16, 2011
Messages
594
Location
Vilvoorde / Flanders / Belgium
8 fun is Bafang.

And voltage/controller makes the power/max speed of a hub motor. Not a lot of 24V motors left, and if you run such one on 36V, a 24V 250W unit would easely draw 550W. But the only thing that could happen is that it overheats. In the end, at least 10% of the input is dissipated as heat.
 
Joined
May 31, 2013
Messages
3,624
Location
South Benfleet, Essex, England, UK
I have Bafang 8-Fun on my Tadpole. If you look on the case there should be a silk-screen printed identifier with BBS01/2 the Voltage and the Wattage.
Mines a 350W, but even the 250W will be more than you need. With bafang's the controller is integral to the motor and the "display head" is just that, a display and configuration/option selection device.
If it's an older one it will probably have the option for a thumb throttle (now banned, but not retrospective).

I have always found the Bafang mid-drive to be a well-mannered unit. :)
 
Joined
Feb 10, 2022
Messages
91
Location
Norfolk UK
Hi Maddox and Danny and thanks for the input.
Danny these are hubmotors as in the pic and I assume you are talking about a mid-drive unit? It's also a sensorless unit I think as there are only three wires exiting the motor which I assume are the phase wires. There is nothing whatever marked on mine- not even a serial number stamped on the casting anywhere.
Maddox I know it will probably work fine at 36v but if it's meant for a 24v supply I would prefer to run it as such (I have several 24v packs and controlers). I'm not sure how I would know for sure which voltage it is as there seem to be loads of 8FUN hub motors mentioned on the net with different voltages but no real identifiers of which is which. If I try it at 24v and it runs well would that suggest it is 24v or would a 36v motor also run ok at 24v?

Thanks
John
 
Joined
May 31, 2013
Messages
3,624
Location
South Benfleet, Essex, England, UK
Hi Maddox and Danny and thanks for the input.
Danny these are hubmotors as in the pic and I assume you are talking about a mid-drive unit? It's also a sensorless unit I think as there are only three wires exiting the motor which I assume are the phase wires. There is nothing whatever marked on mine- not even a serial number stamped on the casting anywhere.
Maddox I know it will probably work fine at 36v but if it's meant for a 24v supply I would prefer to run it as such (I have several 24v packs and controlers). I'm not sure how I would know for sure which voltage it is as there seem to be loads of 8FUN hub motors mentioned on the net with different voltages but no real identifiers of which is which. If I try it at 24v and it runs well would that suggest it is 24v or would a 36v motor also run ok at 24v?

Thanks
John
Hi John, mea-culpa I did not see the pic. It is a Bafang, but a Bafang Hub motor, I was referring to the 8-Fun Bafang mid--drive, which I thought you had - despite the thread title ????? (my bad). :(
 
Last edited:
Joined
Feb 10, 2022
Messages
91
Location
Norfolk UK
Thanks Maddox that means I should be able to tell easily if it's actually 36v which is what I want to know.

No probs Danny. Confusion reigned for only a moment before I realised our wires were crossed.

John
 
Joined
Jan 16, 2011
Messages
594
Location
Vilvoorde / Flanders / Belgium
Standard trick for Roboteers.
Overvolting the 24V 750W motors to 36V gave us 2.2kw of power. Of course the motors overheated and the controllers weren't happy, but the fights are only 3-5 minutes.
 
Joined
Feb 10, 2022
Messages
91
Location
Norfolk UK
There's a lot of stalled motors with those fights too. When the spinning disks suddenly hit a heavy 'bot or tyres get shredded and jam up the batteries and motors must take a helluva hit with the current draw. Plenty of flaming lipo's and smoking windings in some fights. The hundreds of man-hours that must go into those builds for a three minute fight and then going home a bag of mangled bits! Some of those teams must feel like crying?
John
 
Joined
Jan 16, 2011
Messages
594
Location
Vilvoorde / Flanders / Belgium
If you try to work on the bleeding edge of the technology available to "the team", there are compromises.
I remember 1 team that was searching for every gram to get their machine inside the weight limit, and they replaced the steel can what houses the magnets with a carbon tube, and were surprised the motors ran much faster , but almost torqueless.
 
Top