I read all your technical posts d8veh:
"Any Kunteng sine wave controller. PSWPower.com have 17 amp and 20 amp. BMSBattery.com have the S06s 15 amp, but only 36v. Their 48v S12S is about 25 amps (keeps changing), which is powerful, but it's big. They also have a 20amp 48v dolphin battery one, which you can use on its own or get the battery with it already installed."
The PAS levels and the max current settings are two different kettles of fish, I have experimented with my 15 Amp controller which I ran for a time at 11 Amps just to see how it worked.
I don't want a 17 Amp controller from PSWP because I want to have a couple of hub motor wheels to swap in and out and one of them just might be a bit over the top and able to use 25 Amps. In the immediate future I want to run my Mxus at 17 Amps or so. There is the S09S at 22 Amps which is smaller but for once controller box size isn't a problem. I have the 36 V version of the 09 bottle battery controller which I could use (just about) with a 12S battery because the capacitor in it is 50 V IIRC, it would be close at 49.5 V hot off the charger.
I may be running the controller "headless", that is to say with the LCD out of sight so some times I might not know what assistance level I am in. That could be dangerous relying on assistance levels. Assistance level 4 with the S12S is only 12.5 Amps, great for most situations but I live on the blunt end of the Pyrenees...
Those are the points behind my question. And reading between the lines I think you have given me my answer and I thank you!