I looking for a switch not sure what kind though.

[EWILLUSTRATION]

Hey everyone,

I looking for a switch not sure what kind though.

let me explane:

I have 2 sources creating DC 12v

One source works for about 12 hours each day then stops
the other works about 12 hours each day then stops. The next day this is all repeated.

During each 24 hour day one of these DC 12v sources is running a load.

What I am looking for is a switch that will automatically open the circuit "cut the circuit" of the DC 12v source that is NOT supplying power at that time, and keep the circuit closed for the one that is supplying power to the load. Then in about 12 hours later when the other DC 12v is ready it automatically opens the circuit of the DC 12v source that is NOT supplying power and so on.


In summary, when one DC 12v is running the load I want the other ones circuit cut and vise versa.

Hope this makes sense..


Thank You

[Naptown]

How many amps is the load?
If low enough it could be done with a simple double throw relay.

[inetdog]

How many amps is the load?
If low enough it could be done with a simple double throw relay.

Is it important that at no time the load goes unpowered, even for a fraction of a second?
Can the two DC power sources be connected together for a fraction of a second during the transition?
Does the switching logic need to somehow get the information that the second source is ready, or can it all run off a fixed twelve hour timer?

[EWILLUSTRATION]

First Source "this source will fluctuate" BTW this source "the first source" will fluctuate from 12V to 6V
Right now I am getting the below amps at around 5 and a half V
310.2 ma
0.012 amps

Second Source "this source is my backup when the first one looses power" This source "the second source" always has a steady 12V
01.41 ma
0.141 amps



Is it important that at no time the load goes unpowered, even for a fraction of a second? Yes very, must always have current. But then again I don't see why a second would make a difference.

Can the two DC power sources be connected together for a fraction of a second during the transition? I would like to avoid this.


Does the switching logic need to somehow get the information that the second source is ready, I would like it to, lets say if it dropped down to a half volt, it would switch over to the second source. And when the first source achieved a half volt again the second source would shut off. "This would be ideal"


Or can it all run off a fixed twelve hour timer? Cant do timers, because the first source is unpredictable. The first source might work for weeks some times only a half day.

[EWILLUSTRATION]

Anyone have any ideas concerning the question?

[Naptown]

If you can stand a split second of being unpowered (perhaps add in a capacitor for this time but I am no EE) than a double throw relay would work.
You can make this to be controlled by voltage. But again I am no electronics engineer.

[EWILLUSTRATION]

Do you think a 12 v coil 2 pole single throw relay switch would work?

did a little more research. Do you think a 12 v coil 2 pole single throw relay switch would work?

Something like this?
81c1Gvv8QXL._AA1500_.jpg

[Naptown]

did a little more research. Do you think a 12 v coil 2 pole single throw relay switch would work?

Something like this?
[ATTACH=CONFIG]2789[/ATTACH]

2 pole double throw

[SunEagle]

Relay

Even though you listed very low amperage readings you need to be careful and make sure your relay can handle both the amperage of the circuit as well as the ability to break that circuit while energized. Even low amperage circuits can result is some type of arching which will slowly breakdown the contact points.

[EWILLUSTRATION]

Did an illustration of exactly what I am looking for...

Did an illustration of exactly what I am looking for...

zzzzz.jpg

[FunGas]

Couldn't you run both of the sources through its own diode into the load, they're not very much power.

[Naptown]

How the double pole relay works is when the coil or magnet is energized it will feed from the primary source. When the coil turns off a spring will connect it to the secondary source. One problem I with the way you have it wired is once the secondary source kicks in it will feed the primary source bringing the relay back in and will chatter. You need to isolate the two power sources from each other.