Originally Posted by
gigaplex
How was the 3S and 2S connected to the ESC? Sounds like the ground for the servo wasn't at the same voltage as the ground for the ESC, effectively creating a short through the receiver.
Standard serial connection for batteries, as pictured.
If I'm not mistaken, the spc port on the rx (which was receiving 5s voltage direct from the esc battery terminals) is internally separate from the ch 1-4 ports, so I wouldn't expect any issues there, but what do I know, lol. You might be on to something.