Why can’t you use a DPDT Off-Bat-Bat/Alt Master Switch using VPX

[auburnaviator]

I don’t see this Master switch configuration listed in the manual anywhere and I’m trying to figure out why. I know the alt is controlled by the J12-11 pin on the VPX but couldn’t that pin be associated with the “up” Bat/Alt position of the DPDT switch? The “up” Bat/Alt position could be associated to one of the J2 connector 1-10 switch pins on the VPX. I’m sure I’m just missing something simple here and this isn’t listed in the manual for a reason but I currently can’t see it.

If this won’t work, is there another solution without adding a separate SPST alternator switch to the panel?

 

[Brantel]

My RV-7 with a VPX-Pro was configured that way.

 

[auburnaviator]

My RV-7 with a VPX-Pro was configured that way.

Thanks Brantel, so that means it can be done. Any chance you have a diagram to show how it is wired?

 

[N890GF]

This is how I have mine set up as well. I also have the Vertical Power PPS which simplifies it, but the schematic still holds true

 

[Foghorn]

I have a VP-X sport and have OFF-BATT-ALT (far left in pic). The switch is OFF, center is wired to batt contactor and up is ALT field to J2-1(switch 1). Hope this helps.

 

[Brantel]

Thanks Brantel, so that means it can be done. Any chance you have a diagram to show how it is wired?

Two examples above. Easy Peasy!

 

[auburnaviator]

This is how I have mine set up as well. I also have the Vertical Power PPS which simplifies it, but the schematic still holds true

View attachment 116711
View attachment 116715

This makes sense with a ground being connected to both pins 2 and 5 on the switch.

I have a VP-X sport and have OFF-BATT-ALT (far left in pic). The switch is OFF, center is wired to batt contactor and up is ALT field to J2-1(switch 1). Hope this helps.
View attachment 116709 View attachment 116712

This one seems like it would need another ground off of pin 4 on the switch. Or is this just a nuance of the functional drawings and it is assumed that each switch function will have its own ground?

 

[Foghorn]

Zach, I do have grounds off both middle connectors 2/5. I’ll have to fix my diagram to add the other ground and flip the switch around. Mine is 2/5 to ground. 1 to master and 4 to Alt field.

 

[auburnaviator]

Zach, I do have grounds off both middle connectors 2/5. I’ll have to fix my diagram to add the other ground and flip the switch around. Mine is 2/5 to ground. 1 to master and 4 to Alt field.

View attachment 116837

Thanks Jeff. That clears it up!