Yes, you are correct, almost everything regarding Segway scooters are now Ninebot oriented. After Dean Kamen sold the Segway Human Transporter business to an Engish businessman, he died while riding one of his Segways on his estate, fell off a cliff and met his demise. He died intestate and the origninal Segway business was sold to a Chinese company about 2012. The Chinese have proceeded to kill the original Segway design which is no longer manufactured including the original NiMH batteries and I think they also killed the LiON batteries which replaced the NiMH batteries about 2006. Unfortunately the Ninebot models have not proved as reliably helpful for those of us who need an ambulatory aid and even at least one of the battery rebuilders has found the Ninebot systems so difficult to work with they refuse to try to help maintain Ninebot batteries. So that leaves someone with my disability no choice but to try to maintain functionality of the original Segway system with the original technology of the i 167, i 170 and i 180 segway models. I have tried to transition to the later generation 2 Segways with the lean steer method of control which is not nearly as stable as the original rigid upright handlebar generatiion models such that the generation 2 Segways are not helpful for rider stability with only one leg for good balance.
Pictures of the Segway batteries may be confusing if one is not familiar with the two battery padk models (NiMH and LiON)can be seen at:
https://duckduckgo.com/?q=Segway+NiMH+i+167+generation+1+battery+pictures&iar=images&atb=v481-1&t=chromentp&iai=https%3A%2F%2Fcdn.shopify.com%2Fs%2Ffiles%2F1%2F1550%2F6951%2Fproducts%2FFile_000_1024x1024.jpg%3Fv%3D1479516717 The NiMH battery packs (of which two are mounted to the bottom of the standing platform ) consist of two 30 cell 1.2v subC battery arrays in seried producint 36 vdc. for a total of 72vdc power for each battery pack. These batteries were originally produced in France.
The LiON battery packs since 2006 have 18650 LiON cells arranged to produce about 80vdc each. Unlike the NiMH batteries, because of the fire risk, travel with these batteries cannot be used with the airlines. These LiON packs are listed as 10-12 ah capacity which increased the generation 2 Segways range to the 10-12 mile range but as mentioned the lean steer mechanism of the generation 2 units are substantially less stable for someone with a single leg balancing capability, such that they are not nearly as user friendly. For myself using the gen 2 units is not possible. For some of the original gen 1 Segways with software updates both NiMH and LiON batteries can be used. Maintaining batteries howeve is the limiting factor over time as the batteries age out due to recycle depletion. Careful battery maintanence with daily short term recharging is very helpful to maintain battery health but about every 5 years the batteries must be rebuilt with new cells due to natural degradation of battery capacity. When, however, the battery charging circuit in a Segway fails it is obviously destructive for continued use of the unit.
All this data can be confusing to someone unfamiliar with the orginial invention of the Dean Kamen Segway device which originally began with a model designated as "p133" which is now ancient history in the world of Segway human transporters.
So, as you can see, the issue of battery maintenance is of paramount importance, especially the battery charging circuits in the Segway units themselves.
I also have an off board battery charger, but it is impractical for everyday use.