Yeah, I am still using the 2x 3S 1.5ah 9.9v LiFe batteries. The 12v drive motors in Shu! are probably undersized for the Beetleweight class as the stall amperage is 1.2A, so 2.4A for the pair of them. The 12v weapon motor as currently fitted has a 5A stall.

With your figures, though I claim to be no expert here, should be fine if you bear in mind a standard round is 3 minutes. However, whilst there is more to break in a separate circuit system that Shu! uses and uses more weight, the advantage is that if either circuit is broken, the other one will still work and less strain on the batteries as a whole. Single battery setups save weight but it is more of a drain on the battery that is there.

I am sure there is some mathematical calculation to work out the minimum run time with everything running all the time but really, the best way I found is to simply try it. For example, The Honey Badger's 2x 6.6v 2.1ah 30/40c LiFe batteries will last two 3 minute rounds in the Featherweight category before they need charging and that is with it running around everywhere.