Powabyke motor controller suitability

[stemil]

Can anyone tell me if this ebay item would be suitable to replace a burnt out circuit board on an old 21 speed Powabyke Euro, the Powabyke is the type with the kettle lead going to the battery and the console on the handlebars with the push button pedal assist/power mode switch, the motor is on the front wheel.
Unfortunately Powabyke tell me that the correct board is no longer available.

This is the item -36V 36 Volt 800W Scooter Brush Motor Speed Controller | eBay

Any help from the experts would be very much appreciated and if this one won't do the job if somebody could point me in the right direction that would be great.

Regards.

Steve.

 

[NRG]

Do you have a brushless motor? and if so does it have sensors or not? Check how many wires go to the motor and report back....

 

[stemil]

Thanks for your prompt reply, the motor is the brush type. It has two wires.

 

[NRG]

OK, good, is it the same rating as the one you have?

There are some other, lower rating, here:

e-crazyman | eBay

 

[Deleted member 4366]

Can anyone tell me if this ebay item would be suitable to replace a burnt out circuit board on an old 21 speed Powabyke Euro, the Powabyke is the type with the kettle lead going to the battery and the console on the handlebars with the push button pedal assist/power mode switch, the motor is on the front wheel.
Unfortunately Powabyke tell me that the correct board is no longer available.

This is the item -36V 36 Volt 800W Scooter Brush Motor Speed Controller | eBay

Any help from the experts would be very much appreciated and if this one won't do the job if somebody could point me in the right direction that would be great.

Regards.

Steve.

It would work on the throttle,, but it doesn't have a pedal sensor input nor brake cut-offs as far as I can see.

 

[stemil]

OK, good, is it the same rating as the one you have?

There are some other, lower rating, here:

e-crazyman | eBay

I really don't know the answer to that, but I'd sooner go for an overly rated unit.

There's a Brown wire not clearly seen in the photo's which I can only assume is a brake cut-off, this clearly is a must have feature and unfortunately the bike does not have provision for this, can anyone explain how the cut-off works, does it ground out the brown wire?

 

[NRG]

Brake cutoffs usually have two wires not one so not sure what the brown wire is, try asking the seller. D8veh made a good point above about there being no connectors for a pedelec sensor, does your bike have one? Going for a higher power controller could damage the motor and will put more strain on your battery, if its not up to much your range will be low and performance poor.

 

[Deleted member 4366]

I really don't know the answer to that, but I'd sooner go for an overly rated unit.

There's a Brown wire not clearly seen in the photo's which I can only assume is a brake cut-off, this clearly is a must have feature and unfortunately the bike does not have provision for this, can anyone explain how the cut-off works, does it ground out the brown wire?

Just to re-inforce what NRG said: You can't use a controller that's rated higher than your battery and motor. It will try to draw too much current from the battery, which will cause it to cut-out. If you uprate the battery to be able to provide the current, then it'll try and push the maximum current that it's rated for through the motor, which will cause the motor to get hot and eventually burn. The three components need to be matched. Generally, 200/250w motors can take a maximum of 20amps if you don't use full power for too long. A 10aH lithium battery can only give 10 amps continuously and perhaps 20 amps for a very short time. Any more than 20 amps and the BMS will cut the power. SLA batteries can give a bit more for a short time and Lipos can give a lot more. 800w at v36v equals about 25 amps from the battery - just about possible from good 15aH SLAs, but you'd need at least 15aH lithium batteries.

 

[stemil]

I am now begining to realise that I have vast gaps in my knowledge of this subject.
My reasoning for going for an overly rated unit was that I thought the motor would only draw what current was required and that the higher rated unit would be more robust.
I can now see that this is incorrect.
There are some controllers on ebay which are much more suitable and as an added bonus less than half the price.
I really need to bone up on this subject before diving in at the deep end which is what I tend to do.
Cheers guys.

 

[Deleted member 4366]

We all had to start somewhere. Clever people learn from others' mistakes. Normal people learn from their own mistakes. Thickos never learn. That's what my headmaster said to me once, adding that I obviously wasn't in the first category, so he hoped I was in the second.