G'day Hostile.
Maybe I can help.
I'm guessings your EVT 4000E is like these 2 I have lying around.
View attachment 277538
Under the seat, there's a storage tub.
View attachment 277539
Remove the tub and there's the battery compartment.
View attachment 277540
There's no battery box as such. The original 4 50Ah SLAs sit in there with tie down straps, like this in my 168.
View attachment 277541
I've added foam pads between each battery.
If you remove the storage tub you can fit in a 5th battery for 60V. Apparently the motor, controller & DC to DC converter can take it. There's a thread somewhere on ES about it.
The batteries plug in to the four Anderson plugs, seen here from the right hand side of the scooter.
View attachment 277542
I scrawled a wiring diagram for you, hope it makes sense.
View attachment 277543
And the charge socket
View attachment 277544
Pin 1 on the charge socket is positive, pin 5 negative.The original EVT charger is really 4x12 volt chargers and charged each battery separately. Batt 1 is pin 1 +, pin 2 -. Batt 2 is pin 2 +, pin 3 - and so on.
Keep us updated on how you get on mate.
AussieRider