Pas to throttle

[Tom1977]

Hi all, I bought my son a reasonably cheap pas e-bike for Xmas, he’s loved it but now asking for a throttle (illegal in uk but ok on private land) control.
The bike has a 250w (36v) motor with the usual 3x phase wires but only 3hall wires into a julet connector. I purchased a cheap 350w motor controller and throttle kit off eBay and started fitting it.

First issue was their wiring diagram didn’t match what they sent so I had to fart around for ages to get it running. It now runs but as soon as you try to ride the bike and pull the throttle the controller beeps and the motor doesn’t turn ( turns fine if I lift the back wheel off the ground). I may not have the hall wires in the correct place as I have never seen a motor with just 3 hall wires? Why is this? Do they require a specific motor controller?

It runs without any hall wires connected at all, but has same issue. You have to really ‘baby’ the throttle and pedal to stop it from cutting out, but it does eventually get quicker.

Would I be I be correct in assuming that the 250w motor just doesn’t have the oomph to propel a bike from standstill with a 12 stone lad on it? Or is it likely I have the incorrect motor controller for this type of motor. Or something else?!
Thanks in advance for any help.
Regards
Tom

 

[Tom1977]

Hi all, I bought my son a reasonably cheap pas e-bike for Xmas, he’s loved it but now asking for a throttle (illegal in uk but ok on private land) control.
The bike has a 250w (36v) motor with the usual 3x phase wires but only 3hall wires into a julet connector. I purchased a cheap 350w motor controller and throttle kit off eBay and started fitting it.

First issue was their wiring diagram didn’t match what they sent so I had to fart around for ages to get it running. It now runs but as soon as you try to ride the bike and pull the throttle the controller beeps and the motor doesn’t turn ( turns fine if I lift the back wheel off the ground). I may not have the hall wires in the correct place as I have never seen a motor with just 3 hall wires? Why is this? Do they require a specific motor controller?

It runs without any hall wires connected at all, but has same issue. You have to really ‘baby’ the throttle and pedal to stop it from cutting out, but it does eventually get quicker.

Would I be I be correct in assuming that the 250w motor just doesn’t have the oomph to propel a bike from standstill with a 12 stone lad on it? Or is it likely I have the incorrect motor controller for this type of motor. Or something else?!
Thanks in advance for any help.
Regards
Tom

 

[Tom1977]

I guess the battery could be too weak?

 

[m3vuv]

measure the voltage from the battery under load,could be the 350w controller pulls too many amps for the used battery and the lvc cuts juice!.try a bigger bms also or bigger battery!.

 

[pxl666]

it might be a halless controller but they usually say it is . 350w should have enough power but halless controllers have problem starting from zero. they need be in motion for phase sensing . there might be also problem with battery and lastly , you might have fried something when trying different combinations

 

[pxl666]

these wires looks like phase ,speed and temperature . definitely no halls there

 

[Chalo]

Yeah, if there aren't at least 5 small wires (usually red, black, green, blue, yellow), then there aren't Hall sensors. You'll need a sensorless or dual-mode controller that supports throttle operation.

 

[amberwolf]

The bike has a 250w (36v) motor with the usual 3x phase wires but only 3hall wires into a julet connector.

This is probably just a speed sensor--5v (red), speed signal (white) and ground (black).

Motor halls shoudl have five wires (5v, ground, and three separate hall signals, one for each phase).

So you probably have a sensorless motor, and need either a sensorless or dual-mode controller.

It runs without any hall wires connected at all, but has same issue. You have to really ‘baby’ the throttle and pedal to stop it from cutting out, but it does eventually get quicker.

There are at least two possible reasons you might have a problem:

It may require pedal first, in that the wheel may need to be already rotating at least very slightly forward for the controller to correctly detect rotor position and spin it correctly. This is not uncommon in typical sensorless controller systems.

Some of them also don't handle sudden bursts of throttle input very well, and require gradual throttle-up.

AFAICR, the KT controller series has better sensorless operation, if you get a sensorless version (I don't think all of them can do that).


The other possiblity is your battery may not be able to handle the current your new controller is trying to pull, so it is shutting off, then when the load drops it turns back on, etc.

When this happens, all power shuts off, so if there is any display or light on the system powered by the battery, it should turn off when the battery shuts off it's output, even if it's only momentary.

If the battery has a label on it with peak and continuous Amps capability (different from Ah or AmpHours), you can compare that with the controller's current limit in Amps.

The old controller was probably only 6 or 7A, and the new one is probably 9 or 10A. Doesn't seem like a big difference, but that is half again as much current as the original, and the battery may simply not be designed for that. It could be having a problem and voltage sagging to shut off, or it could simply be a protection limit in the BMS to turn off output if current goes that high.