Most e-wheels have settled for the GX16-3 connector. Some though use a different format and the corresponding charger may be difficult to find and are mostly more expensive. A customized charger with the right connector can be made from a generic 2A charger with the wiring instructions below.
Various e-wheel connectors, size and pin comparison
Most frequently found connectors
||1: V+ ; 3: 0V
||connector for Solowheel, Airwheel, Gotway, Firewheel, King Song…
| Gotway MSuper3 84V/1600Wh
||1: V+ ; 2: 0V
||other MSuper3 with battery <1600Wh have GX16-3 connectors
|IPS (Holtz, Zero…)
||2: V+ ; 4: 0V
||warning, same connector as above but different wiring!
|InMotion V8 **
||1: V+ ; 2: 0V
||same connector & wiring as hoverboards
||Int:V+ ; Ext: 0V
||Lenovo square socket, originally for Lenovo laptop power supply
|| see photo for wiring***
|Ninebot Minipro, Xiaomi **
||1: V+ ; 4: 0V
*16S = 16 LiIon cells connected in series, total voltage calculated using battery full value = 4.2V/cell
** important, the numbering order on GX16-3 connectors is totally different from the GX12-3 : from left to right 3-2-1 for GX16-3 compared to 1-3-2 for GX12-3 !!! Likewise for GX12-4 and GX16-4
GX12 and GX16 plugs, note the difference in pin numbering
*** Wiring for Lemo on NinebotOne
Ninebot One’s Lemo female connector
Beware of the charger
For this mod, I recommand using the fanless 2A generic chargers. Even if they tend naturally to warm much more than a (noisy) charger with integrated fan, they have many great features: available for various voltages, noiseless, compact and transportable… They allow fast charging at 4A by a parallel connection with the original charger using a Duo Charge Doctor (or even at 6A with the Triplex CD).
Warning though, some 1.5A chargers are sold as 2A chargers. They have a smaller housing and are very hot when charging, thus unreliable in the long term. When buying it online, the vendor never details the housing dimensions and count on the buyers not checking the actual current to sell it. Any vendor with such dubious practices should be avoided anyway. Without stated dimensions, the difference can still be found looking at the distance between the rectangle and the grooves (see arrows on the picture). So don’t be misled, buy only the 2A charger with the bigger housing.
Chargers 2A and 1.5A, size comparison
Edit 4 dec/2016 : added image from Sylvain. Avoid the small housing charger!!
Small housing charger rated at 2A, too much heat melted the plastic housing.