Switch question!

[BlackDeathsquad]

Hello friends,
       Haven’t posted in a while. This is unrelated but related to pedals. I’m trying to understand dpdt and spdt switches. I’m going to be running 2 different battery packs in a solar set up for off grid living. I want to be able to hook up and use 12v and 110v. I want to be able to turn on and turn off them independently but have them hooked up. Please, help!  TIA…

[IvIark]

A SPDT switch is a single pole double throw.  So you have 3 terminals, a common, a normally closed and a normally open.  So for power applications you would usually use the common and normally open.  When you flick the switch the normally open / common connection closes and you complete the circuit.

A DPDT is exactly the same but with two independent poles.  So you effectively have 6 terminals, 2 commons, 2 normally closed and 2 normally open.  Because they're independant they are electrically separate from each other and so you could use one pole for 12V and the other pole for 110V.

[IvIark]

Or of course you could use two SPDT switches instead so the 12V and 110V power can be turned on and off independently.

[BlackDeathsquad]

Thnx mark…so to running 2 batteries. Battery a going to 110v and battery b going to 12V. Could I use a 4pdt and wire it so battery a is going to 110v and batter b is going to 12v. Switch it and do the opposite? So when one battery goes low I can switch and run the full one. Hope this explanation is ok…😂

[IvIark]

You could do that with a DPDT switch.  If you look at the contact arrangement here:



You can see the two separate poles.  So the connections on the left hand side are the commons and looking at the top one, in it's normal state the common is connected via an internal contact to 1T.  When you flick the switch that connection is broken and the internal contact then connects the common to 2T.

So if you wanted the switch in one position to connect 12V and in the other position connect 110V, you would just connect 110V to the top common, and 12V to the bottom common.  You would then connect Battery A to 1P1T and Battery B to 2P2T.  So in one position 110V is connected to Battery A with Battery B disconnected, and when you flick the switch Battery A is disconnected and 12V is connected to Battery B.

[BlackDeathsquad]

Thnx mark,
    To make sure I’m doing this correct. I’m going to post a schematic. In a few!  Thnx👍