6s or 4s for max efficiency on 10" quadcopter?

Friends! I need your advice based on your real-world experience. I’m building a copter for industrial use, and trying to decide on a 4s3p or 6s2p VTC6 pack. It’s spinning 10" props on 1300kv 2806.5 motors. AUW is about 1200g. The goal is max flight time in a hover and slow cruise. Would you go with 4s or 6s? On this setup the motors will see 3 amps each on average, with a max of 10 amps per motor at 14.7v. I know the logic behind higher voltage being less amps and more efficient, but I’ve also heard that IRL you loose that benefit in mosfet switching losses making 4s ultimately more efficient for our applications. What have you experienced?

I’d say 4S would be better for smaller sized craft, but you could run all the numbers in ecalc to get a better idea. I think you’d only go 6S if you had to, like bigger props and motors.

Jumping to 6S you would need to drop the KV to match the higher voltage and or prop down. The long flight quads (+100 minutes) I have seen posted on RCG are all low kv (under 200) and large props, but thats probably not in your parameters. In 5" miniquad racing, 6s is better because the 4s 2500kv guys are pushing over 100A, and the batteries are not happy in 2 minute races, where 6s, and lower ~1700kv, the batteries are not as abused. Good luck.