Controllers

gucu

Finding my (electric) wheels
Oct 30, 2019
20
1
Hi
I purchased an electric wheel kit from ebay:
The kit is a 1000w motor running 48v and I have a 20a/h 48v battery attached to it. However, it feels significantly underpowered and testing the top speed I am getting 25mph. Someone suggested changing the controller. Is it possible to simply pick a controller, wire it correctly and that will help or do I need to do something else?
Thanks
Rich
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,949
Basildon
Can you give us a link to the exact battery you have?
Does your controller have a label on it that shows the maximum current? If so, what is it?
Do you have the white wires connected? If so, disconnect them.
 
  • Like
Reactions: gucu

Michael Love

Pedelecer
Aug 26, 2018
155
34
56
Last edited:
  • Like
Reactions: gucu

gucu

Finding my (electric) wheels
Oct 30, 2019
20
1
Hi
Can you give us a link to the exact battery you have?
Does your controller have a label on it that shows the maximum current? If so, what is it?
Do you have the white wires connected? If so, disconnect them.
Hi
This is the link to the battery:
No label on the controller.
No white wires connected.
Thanks
Rich
 

gucu

Finding my (electric) wheels
Oct 30, 2019
20
1
What is the current rating of the controller? This site seems to recommend a 35A controller for its 1000W motor.

Have you looked at other adverts for 1000W motor, what battery/controller do they recommend?
Does the display allow you to change top speed in its settings?
I try to have a look at other sites but it got confusing with the amount of options.
There is no display with the controller.
Thanks
Rich
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,949
Basildon
Everything looks about right. The BMS in your battery is only rated at 30 amps, so don't try and replace the controller with a 35 amp one. The speed they quote in your kit's listing is around 28 mph. That could be the no-load speed, in which case 25 mph would be about the right on-the-road speed. You should lift the wheel off the ground and see how fast it goes. If it maxes out at 28 mph, then you'd need a higher voltage battery to go faster. Bare in mind that bicycles become quite dangerous above 25 mph unless you have wide tyres and hydraulic brakes. Even with those things, you'll soon find that riding in any sort of traffic brings a lot of unpredicted dangerous situations. Drivers won't see you or respect you like they would a motorbike.
 
  • Like
Reactions: gucu

Michael Love

Pedelecer
Aug 26, 2018
155
34
56
Buy one of these, open the jaws, put it to 100A and make sure it says DC. Put the +ve wire out of the battery into the round hole and let the jaws close again. Wire should not be in between jawd. see if you can read it while riding it.
This is supposed to measure DC current, so needs to be magnetically zeroed before readings of DC current. You can see at top speed if there is 20A going thru the +ve wire to the controller.
Many instructions how to use online and in the instructions themselves.
Note: You are measuring DC Amps, not AC amps, but I suppose you could put one of the motor wires in the same gap, push the button until the meter says AC and then try again at top speed to see what the reading is for one phase, maybe multiply that reading by 3 to get approx current for all the three phases.
 
Last edited:
  • Like
Reactions: gucu

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,949
Basildon
You can see at top speed if there is 20A going thru the +ve wire to the controller.
You should measure the current at low speed, not high speed. To check your maximum current, lift the motor wheel off the ground and spin it up with the throttle, While holding it at full throttle, slow the wheel right down with the brake and read the current. Don't stop the wheel completely and don't hold it like that too long because the motor will heat up. Just hold it long enough to read the current.

That current meter is relatively expensive. I use one of these.
 
Last edited:

Michael Love

Pedelecer
Aug 26, 2018
155
34
56
Cheaper in Amazon :)

Couldn't resist, bought one clamp meter myself.


The cheaper ones on that auction site are inline are they not, so must connect up Red to Red etc etc.
Although they would be good if you were an avid pedelecer just to see what was being drawn from the battery as you cycle..... Do I buy and fit, or leave well enough alone :)
 
Last edited:

gucu

Finding my (electric) wheels
Oct 30, 2019
20
1
Everything looks about right. The BMS in your battery is only rated at 30 amps, so don't try and replace the controller with a 35 amp one. The speed they quote in your kit's listing is around 28 mph. That could be the no-load speed, in which case 25 mph would be about the right on-the-road speed. You should lift the wheel off the ground and see how fast it goes. If it maxes out at 28 mph, then you'd need a higher voltage battery to go faster. Bare in mind that bicycles become quite dangerous above 25 mph unless you have wide tyres and hydraulic brakes. Even with those things, you'll soon find that riding in any sort of traffic brings a lot of unpredicted dangerous situations. Drivers won't see you or respect you like they would a motorbike.
Thanks for the full and complete reply. Point taken - but I would love to go faster or with more power uphill when I am off-road.
Rich
 

gucu

Finding my (electric) wheels
Oct 30, 2019
20
1
Buy one of these, open the jaws, put it to 100A and make sure it says DC. Put the +ve wire out of the battery into the round hole and let the jaws close again. Wire should not be in between jawd. see if you can read it while riding it.
This is supposed to measure DC current, so needs to be magnetically zeroed before readings of DC current. You can see at top speed if there is 20A going thru the +ve wire to the controller.
Many instructions how to use online and in the instructions themselves.
Note: You are measuring DC Amps, not AC amps, but I suppose you could put one of the motor wires in the same gap, push the button until the meter says AC and then try again at top speed to see what the reading is for one phase, maybe multiply that reading by 3 to get approx current for all the three phases.
Thanks for the reply. Will look to get one in the new year. Looks a useful bit of kit to have in an electric bike toolbox.

Rich