My NG3 was delivered with an cutoff voltage of 136,8V.
With one of the two pots inside, you can adjust the voltage ~10% to ~20%. In my case it is exactly 157,8V max output voltage (+15,35%).
It is important to reduce the current (with the other pot), so the output doesn't get higher than 2160W.
The gray charge curve selector could be a dip switch or a jumper at older models.
My charge curve starts with a constant current and switches into a constant voltage mode and reduces the current until it reaches zero by defined maximum voltage.
Very stable, very easy to use. I plug it in at late afternoon and plug it out next day morning. I drove 1000 miles with the SE/CALBs without a bms.
Our german Zivan distributor is very cooperative and helpful but to change the curves, they have to get the charger or you must order the correct designation of the needed chip, as I understood.
I will get a closer look to my chip and post it.