Plug for M20k

[FBCK]

So I have some new avionics,(new stack) and I wanted to configure the GPS on the ground.  I have the three pronge plug and used a car battery as a power source.  Everything went find but the next time I went to fire up the airplane I was getting a voltage reading of, 11.7 volts.  I'm thinking that my 20 minutes of GPS messing around was using the planes battery.

 

Am I correct in thinking that this method should be using the external power source and not my ships battery when I plug it in.

[KSMooniac]

No, the relay on the external power plug won't open unless the current is high enough to start the engine.  You were using your ship battery.  I'd recommend using a Battery MINDer product appropriate for your battery and just charging up your plane's battery after playing with the avionics.

[FBCK]

So the plug itself is just for starting the plane and even if the current is high enough, its just for starting the plane, it would never power the avionics (correct).

[carusoam]

You should hear the relay close when you connect the external battery if it is going to work the way you think it will...

Scott from Kansas is explaining it differently than I'm familiar with. I'm still working on the details....

Best regards,

-a-

[KSMooniac]

I believe it is only for starting the plane with high current.  Over the years people have tried to use the plug with a low-current/trickle battery charger and they cannot open the relay.

 

I would just go with the Battery MINDer product and install their quick-connect harness & plug.  As long as you don't completely discharge the battery playing with the toys, it the MINDer will charge it up and maintain it properly.

[Ron McBride]

Is your battery getting weak also?   Only used the new radios and only 11.7 volts left??

 

Ron

[RocketAviator]

Im not sure I understand.  I have had my M20K Rocket on external power supply many times and it does not run my ship battery down.  I don't even turn the master switch on as the external power supply enables a relay to the main buss, which is where my G500 draws power from.  I then need to turn on the Radio Master to enable the GTN's.

[FBCK]

The onboard voltage meter was reading 12.1 volts before I started to configure my gps, the engine is not running so the gps is running off one of the batteries, either the one I have attached to the external plug or the onboard battery. After 15 or 20 minutes the voltage meter onboard is reading 11.6-11.7. I assumed the plane was using the external battery, but the next time I use the airplane with no external battery connected the voltage meter read 11.7, so assume it was actually using the airplanes battery. I have a avionics master and a master and the master master has to be on to power the avionics master. That fires up everything, and the power draw is a little heavy, the only thing I can turn off is the second radio with pulling circuit breakers. I understand the updates for the avidyne hfs can take this long, I would not to use the onboard battery.

I do have have a battery minder charger and a one year old canacord battery.

[larryb]

The 3 prong plug needs 12v on two prongs and ground on one prong. One of the 12v prongs energizes the relay. It has nothing to do with starting current. The problem with using this plug with a trickle charger is the current required by the relay will mess with the logic used by a smart charger.