New ebike mod

[fsroque]

Hi guys,

I found a nice entry level ebike at a store sale for about 700 euros and decided to bring it home. This is the bike: http://whitebikes.com/bikes/velo-city-energy-spike/

Overall I am quite happy with it, apart from some quirks. The bike seems to take about 3-4 seconds pedalling before the motor kicks in, and the motor stops spinning immediately if I am not pedalling. As you can imagine this is a pain when going up hill and have to steer from some obstacle or otherwise stop then start again. I am also convinced this engine can give quite a lot more torque than it is giving, and it seems to be cutting off at about 22 km/h. I own a cargo bike with the same engine and it does not exhibit these issues, leading me to think the problem is either in the controller or the computer.

The bike computer is similar to this one, but instead of the 'light' button mine says '6km/h': http://www.dhresource.com/0x0s/f2-albu-g4-M01-EB-69-rBVaEFc7zFWAXFB8AAH_PgtoEno410.jpg/36v-electric-bike-led-displayer-computer.jpg

I was wondering about shunting the controller, maybe changing the computer to something like a Bafang C963 display.

Appreciate any help, thanks.

This is the engine, a Bafang 250W:

The controller:




There's a loose yellow wire here, not sure why, it came like that. Close by were two thin wires, one black and one white, might be related.

The battery holder

The pedalling sensor:

 

[Deleted member 4366]

Thanks for all that detailed info. That helps a lot. It looks to me that there's little you can do to increase the speed with that controller. You can't fit an LCD because your display only has four wires, which means it's analogue. LCDs have 5 wires and use digital communication with the controller. Just in case you don't know, you only get max speed on level 3 (high) on the panel.

You can increase the current for better hill-climbing by putting a blob of solder on one of the shunt's uprights. The shunt is the thing that looks like a big staple at the top of the controller's pcb under the black battery wire.

The delay for the power to come in is programmed into the controller, so you can't change that either.

For about £80, you can get a replacement controller with an LCD and a throttle that responds instantly to the PAS. To install it, you'd need to do a bit of wiring. You can install it in a tool bag in the frame or behind the seat, and run the battery wires directly from the battery connections and out of the controller compartment. You can remove or leave the original controller, though it would be easier to remove it with all the original wires.

It looks like your motor is sensorless (3 wires only). Can you confirm that?

This is the sensorless controller that I'd recommend. You can set the speed to whatever you want. It uses current control for the PAS, which means that you can set the power low or high (5 levels). Your one almost certainly uses speed control, so you get three different speed limits from the panel.

http://www.pswpower.com/peng/iview.asp?KeyID=dtpic-2016-3F-43TE.50CTN

 

[fsroque]

Thank you for the detailed explanation, it was very useful.

I can see the bundle of wires going out from the controller into the engine have 3 thick (yellow, green, blue) and 3 thin wires (red, yellow, blue).

I went ahead and did the shunt mod. Picture before and after are below. Was my first mod so I took it easy on the solder; there was already a small blob there, and I basically doubled it. Results are satisfactory, I can feel the bike snappier on the uphills (there are a lot here). My commute is short (about 5km), but since most of it is up and down steep hills I think I shouldn't be pushing it too much. One think I noticed is that when climbing a hill with a fresh battery, the leds indicating battery percentage usually drop one or two points (2 or 3 lit leds instead of the 4). Is this voltage sag?

Took a picture of the underside of the metal plate where the controller is attached. The controller is from Brainpower. Did not have much luck googling it.

I am tempted to order the controller you recommended. If anything I can experiment with the other bike as well (the picture of the other controller is below). I have a few questions:
1 - Square vs sine wave - I see pswpower has one sine wave for the same price, any particular reason why I shouldn't take it? is it 'fake' sine wave controller?
2 - Throttle - is this necessary? Or is it somehow an override from the PAS sensor?
3 - PAS - is any of the options there (ten poles or dual hal) better than what I currently have?

Thanks!

Before the shunt mod



After shunt mod:

The controller for the other bike (a cargo bike)

The 'Brainpower' controller.

 

[Deleted member 4366]

The leds going out when you use power is voltage sag.

The sine- wave controllers are normally only for sensored motors. Yours is sensorless. the other wires are probably a speed sensor.

The throttle isn't necessary, but can be useful. if you install one, the bike still works like you want with the PAS, but any time you use the throttle, the throttle will take precedence, so you get instant power on demand, then, when you let go of it, you're back to normal PAS operation.