Controller Ratings

[szeitz]

Hello all,

I've been looking around for a new controller.
But something is not clear to me. One seller has a controller which is 36V 350W and only 8A limit. So how could that be suitable for a 350W motor if the 8A is not even 350W (36V*8A=288W), the most the controller will handle.
But other have 36V 250W which has 17A cut-out limit. Would that mean I could just go for the 250W version, as it has enough current?
My current controller is 36V 350W an 17A as well.
So what's the difference between the 350W and the 250W model.

Thanks for the help in advance.

 

[NRG]

Hello all,

I've been looking around for a new controller.
But something is not clear to me. One seller has a controller which is 36V 350W and only 8A limit. So how could that be suitable for a 350W motor if the 8A is not even 350W (36V*8A=288W), the most the controller will handle.
But other have 36V 250W which has 17A cut-out limit. Would that mean I could just go for the 250W version, as it has enough current?
My current controller is 36V 350W an 17A as well.
So what's the difference between the 350W and the 250W model.

Thanks for the help in advance.

That will probably be the continuous rated current, the controller may have a maximum burst rating.

Look at this E-crayman auction, 350W / 36v but rated for 25amp peak:

36V 350W brushless controller for E - bike & scooter on eBay (end time 09-Dec-10 13:48:28 GMT)

350W at 36v is nearer to 10amp continuous so 8 may be a typo.

 

[ronipozn]

Usually the controller ampere limit is what is the maximum ampere which the controller should and can handle.

 

[NRG]

Depend on what amp limit you are talking about, phase, battery or peak. A 250W controller can be set for say a 15amp battery limit but its continuous rating may be lower and the phase current could be a multiple of the battery current when the controller is workin in PWM mode.

 

[jbond]

I've been looking around for a new controller.
But something is not clear to me. One seller has a controller which is 36V 350W and only 8A limit. So how could that be suitable for a 350W motor if the 8A is not even 350W (36V*8A=288W), the most the controller will handle.
But other have 36V 250W which has 17A cut-out limit. Would that mean I could just go for the 250W version, as it has enough current?
My current controller is 36V 350W an 17A as well.
So what's the difference between the 350W and the 250W model.

What motor and battery are you running. Because that has a big bearing on what capacity of controller you're running.

NRG has a photo above of a Bafang controller to go with a Bafang 250w motor from Alien. My Aurora has the same controller for a 36v350W Bafang BPM motor (also from Alien) but shows 9A rated, 19A max on the sticker. E-Crazyman's controllers are typically described by their max current. A 15A controller is probably fine with it's stock settings for a 250w motor. (I think). You can probably fit a 20A controller with no problems as well. See
http://www.pedelecs.co.uk/forum/electric-bicycles/5274-alien-gents-special-ii-improvments-modifications.html

 

[szeitz]

What motor and battery are you running. Because that has a big bearing on what capacity of controller you're running.

NRG has a photo above of a Bafang controller to go with a Bafang 250w motor from Alien. My Aurora has the same controller for a 36v350W Bafang BPM motor (also from Alien) but shows 9A rated, 19A max on the sticker. E-Crazyman's controllers are typically described by their max current. A 15A controller is probably fine with it's stock settings for a 250w motor. (I think). You can probably fit a 20A controller with no problems as well. See
http://www.pedelecs.co.uk/forum/electric-bicycles/5274-alien-gents-special-ii-improvments-modifications.html

Hello, thanks for the replies.
I am running a 36v 350w rear hub with 3x 10Ah SLA batteries.

 

[aseb]

What motor and battery are you running. Because that has a big bearing on what capacity of controller you're running.

NRG has a photo above of a Bafang controller to go with a Bafang 250w motor from Alien. My Aurora has the same controller for a 36v350W Bafang BPM motor (also from Alien) but shows 9A rated, 19A max on the sticker. E-Crazyman's controllers are typically described by their max current. A 15A controller is probably fine with it's stock settings for a 250w motor. (I think). You can probably fit a 20A controller with no problems as well. See
http://www.pedelecs.co.uk/forum/electric-bicycles/5274-alien-gents-special-ii-improvments-modifications.html

What would the consequences be for fitting larger amp controllers? For example 30A and for a 40A one?

 

[NRG]

On a geared motor failure of the nylon gears. The big amp controllers tend to be used on direct drive motors to increase torque. On the Bafang 250w motors 15amp is a safe limit but I'm running just over 20amps but I treat the motors gently from standstill and make sure it does not strain too much on hills by keeping the speed as high as possible.

 

[aseb]

On a geared motor failure of the nylon gears. The big amp controllers tend to be used on direct drive motors to increase torque. On the Bafang 250w motors 15amp is a safe limit but I'm running just over 20amps but I treat the motors gently from standstill and make sure it does not strain too much on hills by keeping the speed as high as possible.

I wonder if it is nylon gears in the x-byke motor- I've never found out who the manufacturer is, or which model is used.

 

[flecc]

I wonder if it is nylon gears in the x-byke motor- I've never found out who the manufacturer is, or which model is used.

It's practically certain they are, steel gears are very noisy and only normally used on motors with well over the
legal power rating.
.