Those kettle style connectors (we call them house plugs and ports) have recently started being used by electric scooter manufacturers for higher Amp battery to controller connections, however, a high Amp plug with molded in thick gauge wires would be needed for that and a common solder-on plug would not be able to handle the high Amp load that a 48 Volt 2000 Watt motor and controller would demand from the battery pack. We do not currently carry any high Amp house plugs so switching over to a different style connector is recommended.
We carry the connector that matches with the connector on the controller (item # CNX-82M for $1.19) on this page: https://electricscooterparts.com/large-black-wire-connectors.html
Two wires may be able to be crimped and soldered to this connector's terminal as long as the wires are not too thick. Another option if the wires are too thick would be to solder a single wire to the two wires, cover the exposed conductors with heat shrink tubing, and then attach that single wire to the connector terminal.
The XT90 connectors could handle the power of that scooter, however, installing them would definitely require the two to one wire method so there was one wire to insert into the XT90 terminal hole before soldering. Using the XT90 connectors would, of course, require that both the battery pack and controller connectors are switched over to it also as opposed to only needing to switch the battery pack wires over to a CNX-82M connector.
House plugs and ports push together and can fairly easily be pulled apart, XT90 connectors snap together and can be pulled apart by hand, CNX-82 style connectors have a locking latch that keeps them together until the latch is pressed so they can not be pulled apart or vibrate apart unless the latch button is pressed. So, for this reason, the CNX-82 style connector is what we recommend using.
Please let us know if you have any questions.
I checked and could not find any manufacturer name or part number imprinted on the connector or terminals so unfortunately, I do not have any information that would help you to search for it locally.
The XT90 connectors do hold together rather well and are often used on remote control vehicles that move around a lot so they would be a suitable alternative, especially if a strong tape was wrapped around them after they were plugged together.
Due to the high amount of power that lithium batteries can produce working with live lithium battery pack wires needs to be handled with extreme caution to avoid creating a short circuit. The two red wires could be twisted together and inserted and soldered into the terminal so long as they both fit inside of it. If they do not fit then they could be joined with solder to a short piece of thick gauge wire that does fit into the terminal. The same of course goes for the two black wires.
For a very short piece of wire the gauge can be smaller than for a longer piece of wire. We recommend using the largest gauge wire that will fit in the terminal such as 10 gauge or 12 gauge. The scooters original battery pack wiring harness had a fuse in it and for safety, a fuse should be installed between the new lithium battery pack and controller.
On that type of scooter, the fuse is commonly located in the battery pack wiring harness near the batteries. The rating of the fuse should be selected depending on the battery pack's maximum continuous power output rating and the scooter's original fuse rating. Whichever of these ratings is lowest is the fuse size that should be used. We do not know what these ratings are so they would need to be obtained from the distributor or manufacturer of the battery pack and scooter.