This one:
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It's a "1T4", but not a Bafang one, which is different. This is just an example, there are lots of sellers on eBay in China and HK selling them, just check it's the right one.
I have an L6 controller and I was using the brake connector in reverse, as a "dead man's handle", ie, unless I was pressing a button on the handle bars, the motor would not cut in. I find PAS annoying and dangerous, having it kick the motor in at full power, just when you rotate the cranks to change down coming up to a junction. But then the LCD stopped responding to the button signal. It was also getting condensation inside and I thought it would be good to get a better display. Then I found they all seem to be 5 pins for KT LCD units.
I saw Bafang doing a 1 to 4 cable for their mid drive kits, but it doesn't use an 8 pin connector for the controller. I did a lot of searching on eBay and eventually found the one above. A lot of the newer controllers seem to be coming with these 8 pin Julet connectors now and they need such a cable. However, it's a good idea to check the gender. This one is male on the cable and I think the DAS KIT one is male too, so they would need a gender changer. I haven't had a chance to play with things yet, but the cable that comes with the DAS KIT system from the controller to the LCD might change the gender...I need to unplug, check, plug and have a play...but just so long as you are aware and prepared. I might have to cut the connectors off entirely splice the wires together and get the soldering iron out!
Yes, I didn't really want to spend more money on another LCD, but there seems to be a lot more choice out there with the KT system, and this adaptor cable enables you to use them. Some KT LCDs look like spaceship displays
and with the brake cable separate, I could re-instate my dead man's handle. In addition, you might want to upgrade your controller. The stock DAS KIT unit I have is only 14Amps and you can't mod it because it is resin encapsulated, which is annoying.
I've seen some stuff recently about that on the web. A forum in the US had translated some stuff from a German site where they had hacked the firmware and intercepted the signals to and from the controller and LCD. I thought it looked interesting, but a bit over my head, so I didn't bookmark it. I'll see if I can dig it out...