It is probably a halong-2 case but all the brackets seem to have 5 prongs instead of 4 which mine has. Of course, there is absolutely no help from Rattan ebikes. Rattan has this I-Pas regeneration technology, and it does work. I have been down to 4 bars and then descended a very steep, long incline, and it came up to 5 bars. I am going to try this 77 mile ride again, the last 35 miles descend about a 1000 ft. so I might be able to regenerate enough with 4 bars to make it. If so, my need for the extra battery goes away. If one tried a cross USA ride on an e-bike, though, an extra battery would be absolutely essential.
One battery manufacturer, Ankloss, says that the majority of discharge connectors are either an Anderson or XT60, but the latter is probably soldered in. It looks like I can remove a plate attached by two bolts and see the connection more clearly, then could go from there.
If anyone knows which of the two connectors it might be, that is, if one of those two, let me know.
BTW, I still have not figured out why whether I set at 3,5, or 9 levels, I do not get any assist over about 15-16 mph. I have all the info on the parameter levels and have tweaked them all, but still no change.