Temperature Sensor

[baldbas]

I have a bike with a Bafang B Fun 250w 36v motor that cuts out due to a faulty temperature sensor
I am told t must replace the motor, is there any way i can disconect the sensor? Thanks.

 

[rich c]

I didn't even know they had a temperature sensor. Never heard of it.

 

[AHicks]

What has led you to believe a temp sender is causing your motor to cut out?

Could this temp. sender be in the controller?

 

[baldbas]

Hi It`s fitted to a Volt Alpine that i that bought new from the local Volt agent, The motor cuts out under any load,
the volt people changed the controller but the fault remained, I have been told by them that the fault is due to a
sensor in the motor that cuts out if it overheats failing, It cannot be repaired and the motor must be replaced
at a cost of over £400. When it`s working it`s fine full power-no noises, only done 2500m Regards.

 

[Gionnirocket]

Sounds more like a thermal cut out rather than a temperature sensor.
A sensor would be wired into the controller and could be bypassed.. but if there is a thermal cut out it could be part of the internal motor wiring. When functioning properly they should only open under a high temperature situations and reset when the motor cools down. If it is working properly, it's probably saving you from burning up your motor. If it's not working properly and is opening prematurely the only way to bypass or replace it would be to open up the motor.
If you are able to use the motor with some reliability, I would suggest going easy on it... It's not a very powerful motor to begin with.
If you aren't, you have nothing to loose by opening up the motor which might not be as easy as it sounds as some are not meant to be serviced and only go together correctly once.
Good luck

 

[harryS]

I've not seen a temperature sensor in my two bafang rear hub motors, nor in any other motor taht I've bought. There's usually only one extra wire available in the 9 pin cable seen on most Bafangs, and a speed sensor is the more common option.

If you just cut the wire, the controller still might shut down. Best is to disconnect it and wire it to a sensor outside the motor. It would not protect the motor, but the controller would be fooled. I'd do it all inside the controller for a neat package.

This assumes your dealer isn't incompetent with their diagnosis.

 

[AHicks]

Hi It`s fitted to a Volt Alpine that i that bought new from the local Volt agent, The motor cuts out under any load,
the volt people changed the controller but the fault remained, I have been told by them that the fault is due to a
sensor in the motor that cuts out if it overheats failing, It cannot be repaired and the motor must be replaced
at a cost of over £400. When it`s working it`s fine full power-no noises, only done 2500m Regards.

Do you have another shop available? Maybe time for a second opinion. Would be nice if you could find a shop willing to pull the motor down if necessary.....

 

[tomjasz]

Bafang B Fun 250w 36v motor

Which motor? BBS01B or?

 

[tomjasz]

I've not seen a temperature sensor in my two bafang rear hub motors,

Later versions of BBSHD and BBS02B do have temp sensors. These motors are subject to overheating when lugged.

 

[AHicks]

Is it considered a "serviceable" item with replacements available?

 

[tomjasz]

Is it considered a "serviceable" item with replacements available?

The BBSxx series temp sensors are buried in the controller potting material.

 

[harryS]

The Alpines looked to be hub motors to me.

Electric Mountain Bike | Volt Alpine

Details for Volt Alpine electric mountain bike. Go anywhere on this great looking and tough ebike.

voltbikes.co.uk

 

[Gionnirocket]

The Alpines looked to be hub motors to me.

Electric Mountain Bike | Volt Alpine

Details for Volt Alpine electric mountain bike. Go anywhere on this great looking and tough ebike.

voltbikes.co.uk

... and it doesn't seem to be a Bafang motor either?
SpinTech™’s 250 watt motor

 

[Gionnirocket]

The BBSxx series temp sensors are buried in the controller potting material.

That's interesting... and good to know, thanks Thomas!
Do any of the displays have the capability of utilizing the data from the sensor?

 

[AHicks]

It's probably a thermal switch. It get's hot enough and breaks the circuit. Like a circuit breaker that automatically resets - or a turn signal flasher if you're familiar there (bimetallic strip with a set of contacts).

 

[tomjasz]

That's interesting... and good to know, thanks Thomas!
Do any of the displays have the capability of utilizing the data from the sensor?

No such display.

 

[Gionnirocket]

No such display.

Seems like a waste of hardware capabilities.

Do you know how it works? Is it wired into the controller at all?
You wouldn't happen to know if there is a motor/controller wiring diagram? ...like those found in US manufacturer repair manuals.

 

[AHicks]

I have a pretty good bet. The hall sensors all share a common side. That would be the place to put something like a thermal sensor. It's doesn't care about polarity. It's pretty much just an off and on device - which is why it could not be used to feed a temp gauge. There's no variable resistance to it like a temp sensor would have. It's all in, or nothing!

 

[tomjasz]

Seems like a waste of hardware capabilities.

Do you know how it works? Is it wired into the controller at all?
You wouldn't happen to know if there is a motor/controller wiring diagram? ...like those found in US manufacturer repair manuals.

Yes, it works by shutting down the motor. Bafang will not release a parts breakdown, much less a schematic...

"There are actually 2 temp sensors - 10k thermistors - one in the controller and one in the motor.."

 

[Gionnirocket]

Yes, it works by shutting down the motor. Bafang will not release a parts breakdown, much less a schematic...

"There are actually 2 temp sensors - 10k thermistors - one in the controller and one in the motor.."

Sounds like time to do an autopsy!