Help needed to replace a faulty LED dispay

[TomBrown]

Hi


My LED Display on my Bafang 8Fun kit needs replacing. My kit is as follows:


1. Bafang 8Fun SWXK36V250W brushless motor, No Hall, in a 26” Wheel.

2. Controller for Brushless Motor LSW903-5-2. 36v Max Current 15A, Rated 7A, Low voltage Protection 29v, Throttle adjustment 1.2v – 4.4v

3. LED Display 790-36-1800. Functions: Power: On/off, Battery Level, Switch between PAS/Throttle, Mode: Low, Medium, High PAS.


The LED Display has a 4 wire Connector (Red, Blue, Black, Green) I assume the are 36v, Lock(Power on/Off), Ground and Signal (not sure) respectively. The display is over 5 years old and I cannot find a replacement on the web.

I have seen a similar 880 LED Display which has a 5 Wire connector (Red - 36v, Blue - Lock(power on/off), Black - Ground, Green TX, Yellow RX).

Are the Tx and RX data lines?
Is this a new standard interface?
Do LCD displays use the same interface?

So I assume I will need to buy a Display and Controller pair.

Can anyone recommend suitable replacements to drive my bafang 8fun brushless no hall motor?
Do all no hall brushless controllers have a standard 3 wire interface to the motor?

I have seen an 880 LED display or LCD Display with a Kunteng KT36ZWS-FZ15E controller for sale on ebay by Panda Bikes ltd would these be suitable replacements to get my bike up and running again?

Tom

 

[Deleted member 4366]

The green wire is analogue singnal: level 1, 1v; level 2, 2v; level 3, 3v; 6 km/h walk mode, 4v.

The 4-wire ones are still available. You can't use a 5 wire one because they're digital, except if they have a light switch, when there's a 5th wire to csrry battery voltage to the lights.

http://www.aliexpress.com/item/24V-36V-250W-6Mosfets-E-Bike-Motor-Controller-with-LED-meter/32219870322.html?spm=2114.32010308.4.115.DrUqv5

 

[TomBrown]

Thanks for your prompt response and link I am looking for a 36v version.

Is the 5 wire digital interface the latest standard?
Is the 5 wire digital interface used by LCD Displays?

 

[Deleted member 4366]

The LCDs are digital. Thet have red 36v, black ground, orange or blue 36v switched and two others, which are tx and rx data. The analogue LED panels do seem to be dying out now.

 

[TomBrown]

If I go for a LCD display I will need to get a new controller as well. Will most 36v, 15A brushless (no hall sensor) controllers work with my bafang 8Fun QSWXK motor or do they need to be programmed/matched up.

 

[Deleted member 4366]

Yes. Get them as a pair. No programming is necessary. Occasionally, the motor wire sequence needs a bit of trial and eror gor sensored ones, but if yours is sensorless, it won't be a problem for you. BMSBattery do the S06P, which should work with a sensorless motor.

 

[TomBrown]

Yes. Get them as a pair. No programming is necessary. Occasionally, the motor wire sequence needs a bit of trial and eror gor sensored ones, but if yours is sensorless, it won't be a problem for you. BMSBattery do the S06P, which should work with a sensorless motor.

Thanks for your help. Just had a look on BMSbattery at the SO6P controller and S-LCD1 the pair will cost £27.96 plus delivery and import duty. I will probably need some other bits brake sensors and PAS as connectors are different so total is about £40 pus delivery and import duty. They also do a SO6PW water proof connector kit which includes the S-LCD1 and brakes, PAS, throttle with a neat cabling harness which looks nice for £39.96.

They quote the the SO6P as 24v/36v does this mean it will handle either battery voltage as most controllers I have seen are battery specific.

Do these controllers sense the speed from the motor signals.

 

[Deleted member 4366]

You won't have to ay duty on something that small.

They are compatible with 24v and 36v. They have auto-sensing for it.

They can get the speed signal from the motor or an external wheel speed sensor. If it's a geared motor without a hub-speed sensor, it will show zero speed when freewheeling, in which case you need a wheel speed sensor.

 

[Nealh]

The leccy kit bundle option makes sense as the wiring is neater and no fiddling with connections also added nice w/proof plug and play connectors.

 

[TomBrown]

You won't have to ay duty on something that small.

They are compatible with 24v and 36v. They have auto-sensing for it.

They can get the speed signal from the motor or an external wheel speed sensor. If it's a geared motor without a hub-speed sensor, it will show zero speed when freewheeling, in which case you need a wheel speed sensor.

I have not purchased from china before, what is the best delivery method and typical cost. I have just had a reply from Panda bikes and they have quoted me £69 for there kunteng controller and LCD.

 

[Nealh]

£62.43 delivered form BMSB, so Panda option is good with back up.

 

[TomBrown]

£62.43 delivered form BMSB, so Panda option is good with back up.

Sorry to confuse you but we are not comparing like with like, I have just been on BMSB myself.

You are correct in saying the SOP6W kit is £62.43 delivered (£39.96 parts + £22.47 shipping) the £22.47 is there minimum shipping cost. The SO6PW kit includes the LCD display, Controller, PAS, Brakes, Throttle and waterproof 4 to 1 cable.

The equivalent Panda ebay price is £110.

The £69 I was quoted was for Controller and LCD display only. The BMSB price for these are £27.96 + £22.47 shipping = £50.43.

 

[Nealh]

In that case then the BMSB kit is the one I would buy.

 

[TomBrown]

I am trying to decide between the BMSBattery SO6PW kit which has reduced cabling but uses a pair of aluminium brakes or making a kit up around the standard SO6P controller which uses in-line brake sensors. I am not sure if the SO6PW controller has a connector for a speed sensor so I have emailed BMSB. Both work out at about £60 delivered.

I was thinking of possibly buying 2 kits or some extra bits for spares to make the most of the delivery charge. From your experience when are you likely to be hit for import duty, is it about 20%?

 

[Deleted member 4366]

It's easy to add an external speed senor, even if it doesn't have the connector.

 

[TomBrown]

It's easy to add an external speed senor, even if it doesn't have the connector.

That makes things easier. Are the in-line brake sensors reliable not used them before.

 

[Deleted member 4366]

They're reliable, but the cable must be free-running. It's probably better to just fit a single one to the back brake.

 

[TomBrown]

It's easy to add an external speed senor, even if it doesn't have the connector.

How do you add an external speed sensor if there is no connector on the controller to get around the freewheeling issue.

 

[Deleted member 4366]

You can use a two wire one of a cycle computer. You connect one side to any 5v red wire, like on the throttle or PAS, and the other to the white wire that comes out of the motor connector onto the controller's pcb. You just cut it and join the sensor wire to it. Alternatively, you can use a proprietary 3-wire one, which is the same except you also have to join its ground wire to any black.

 

[TomBrown]

You can use a two wire one of a cycle computer. You connect one side to any 5v red wire, like on the throttle or PAS, and the other to the white wire that comes out of the motor connector onto the controller's pcb. You just cut it and join the sensor wire to it. Alternatively, you can use a proprietary 3-wire one, which is the same except you also have to join its ground wire to any black.

My motor only has 3 wires green, blue,yellow.