I use a dual battery regulator for my receivers in my jets - usually a Smartfly one, with two 2S LiPos. The regulator draws power for the receiver from whichever battery has the higher voltage. I run my Electron retracts off of one of those batteries. I have telemetry to read the voltage of both batteries. When the retracts are in motion or the brakes are on, you can see the voltage of the one battery go down a few tenths, but as soon as the draw from the retracts/batteries stops, the voltage recovers. If the retracts/brakes ever over-draw the battery, the other one will take over and power the RX until I get back on the ground...

Bob