So the batteries are definitely fully charged and the connections between them and the ESCs are in good condition? I'd verify those first before calling it - the original Badger suffered from this sort of problem due to shoddy soldering and even the current one can suffer from this if I've only got one side connected up properly.

One final question, is the LED light mandatory? As I think the ones I replaced them with shorted out... and if that's the case, then I'm going to have to go on the hunt for more LED lights that can handle 18v... or as the battery charger likes to say "21"... not sure if that's the actual voltage, but okay...
Yes, the LED lights (I'd go for two lights - one for drive and another for the weapon) are mandatory. I have uprate the lights on mine due to the voltage jump from 13.2v Nominal to 19.8v Nominal. Something like this that goes up to 24v apparently- https://www.ebay.co.uk/itm/1-Cabled-...53.m1438.l2649