Greetings:
I want to know if plugging in External Power, 3 pin. at the port on DaPlane will charge both batteries. I have dual 24V batteries- Gill G246 lead acid.

Do I have to turn the cockpit GPU switch to on, plus turn the single battery master to on?

I would like to keep the battery charger’s input away from systems. Battery charging only
using a single 24V battery charger.

Is this possible?

Jimmy
You'll have to tell us what you have for an aircraft so the specific experts can chime in with their experiences and knowledge base.

Paul

Our TBM850 has a connection wired in place direct to the battery connector that allows a Concorde Battery specific Batteryminder to be connected and charge and maintain the battery.
All done without turning anything on via cockpit switches.

As others said, it's system specific so you'd need to know your system. That said, it's unlikely - most GPU ports are not designed to be able to charge the battery.

Others are welcome to chime in and show examples of systems that prove me wrong.

I tried things out and unfortunately, had to l.e.a.r.n.
1- Battery charger through GPU switch puts the charger on the aircraft busses, but not on the batteries.
2- To charge the battery via the GPU source, turn on both GPU and battery switches.
* problem with that is the battery charger and batteries are on the busses*

3- Now, I know how IA Richard Pahanke of Plane Design, KLHZ airport NC, ruined the following equipment on my airplane.
He was charging via GPU because he wore the batteries down trying, and failing, to set up Fuel Injection on the two new IO470’s.

Items destroyed by the shop owner above, at my expense:
Stec65 Autopilot with optional HSI $12,000
GNS480 $6000
Terra Radar Altimeter $3000