Sensor or Sensorless?

[Ajax]

Hi all, i'm looking to replace my existing controller with one which can work with or without the hall sensors connected. Question. If, for the reason of making fewer connections, i connected the controller up without the hall sensors, would this make much of a difference to the performance of the motor? Why would motors have hall sensors if its possible to function without this feature?

Also my existing controller is 36v 250W 12A with 120degree phase[??]. The new controller 36v 250w-360w 10A, with no mention of the phase, which i believe can be 60 or 120 degrees. What can i expect besides lower torque?

Sorry for newby questions.

 

[Old_Dave]

would this make much of a difference to the performance of the motor? Why would motors have hall sensors if its possible to function without this feature?

Some motors have hall sensors and can perform ok when they are not connected .... and some don't.

Issues can be problems with motor noise, rough running at certain rpm and excessive current

As most motor cables are multi core with a multi way plug / socket, the saving of the hall sensors isn't really worth while (you only have to connect them once..)

 

[NRG]

Torque will be fine, the sensors are used to detect phase on start up so controller and motor combos using them are a bit smoother starting up from standstill. The sensorless controllers have to work out what way the wheel is rotating by first pulsing the motor phases to detect the direction of rotation so with these controllers the motor gives a little hiccup from rest but once spinning are just the same as the ones using sensors.

One reason not to use sensors is reliability...

 

[jackhandy]

None of my business, really - feel free to tell me to mind me own business - but isn't going from a 12a controller to a 10a one a bit of a retrograde step?

 

[Deleted member 4366]

Sensored is always best if you can. It's usually smoother and more efficient.

You have to be careful of controller ratings: Is it 10A normal running or 10A max?. If it's 10A max and you want more power, solder the shunt.

 

[Ajax]

Sensored is always best if you can. It's usually smoother and more efficient.

You have to be careful of controller ratings: Is it 10A normal running or 10A max?. If it's 10A max and you want more power, solder the shunt.

Yeah, i think i will connect the sensors, however not with the connectors supplied. As for the shunt, i'll have a go at that too. What happens when the wheel attempts to take more current than the battery is rated for?

The battery is quite modest at 36v 9amps. Would this result in the loss of power? Eg, would the bms cut the power if you exceeding the max current draw for the battery? I've notice this is a lot worst in deregulated mode, and also that a lot more grunt is required in deregulated mode.

 

[Deleted member 4366]

Try it first in case they mean 10A continuous, which means 20A peak. If it's 10A peak, solder about half the shunt. You could try 1/3 first and see how you get on. You battery should be OK. I've a 9AH frog battery which seems happy with the controller at 17 amps. I wouldn't go more than 15A if you have one of the cheapo 8.8AH bottle batteries.

If you overload the battery, the BMS would cut out, but you'd have to over 18A for that, but you might notice the LVC cutting power temporarily when the battery's approaching empty and you put the motor under heavy load - like hill-climbing.