Help! Inflight voltage telemetry

[FlynBrew]

I’m trying to set up voltage telemetry on a plane build. I have the FT 40a BLHeliS ESC, RM ER6 Receiver, and (maybe not as relevant) RM Pocket transmitter. Not sure where to connect a wire to enable this telemetry. Info on the receiver implies this is possible without extra voltage sensor, but I’m new to this and not sure how to set it up or if I’m just wrong.

 

[LitterBug]

The EXT-V socket is for voltage monitoring.

 

[FlynBrew]

The EXT-V socket is for voltage monitoring. View attachment 242908

And where does the other end connect? It came with a wire that fits the ext-v plug but the other end is bare.

 

[LitterBug]

Connect it to your battery leads. Maybe at the ESC.