Adding Inverter to Existing Transfer Switch

[booster]

Originally Posted by avanti

I agree with your diagram (except for the minor point that "DC in" and "DC out" are the same wire).

But I still don't understand why you said this:



Your diagram illustrates that it works either way.

For me DC in and DC out would always be in relation to the device, even if they are tied together later, but yes they are the same wire. I thought it would be easier to picture as being able to go both ways and show where they connected. For the battery the in and out would be opposite by my definition.



You are correct on the second one, as I was looking at inverter functionality only and the inverter would work OK with genny directly to it's internal switch, but operator error could still get two on at the same time. You could also hook the genny up to the inverter output if it had no transfer switch, but you could still get two outputs that way with error, so not a good idea.

[WayneS]

Yes that's a good idea. The AC line common point in the breaker box would need to be isolated for the charger on the hot side. You might need a separate breaker. If your inverter has a charger it could be used but it's not included in the power limit manager.

[booster]

Originally Posted by WayneS

Yes that's a good idea. The AC line common point in the breaker box would need to be isolated for the charger on the hot side. You might need a separate breaker. If your inverter has a charger it could be used but it's not included in the power limit manager.

How the AC gets wired for fusing and breakering depends a lot on the size of the charger, inverter, inverter/charger, I think.


For our system the AC power cord comes directly in to inverter/charger. There is no breaker in that line as it is 10ga so 30 amp rated like the shore cord. That cord an wiring is protected by the shore power breaker at the post. We have no generator to worry about. The inverter charger is rated for 30 amp pass through and less than that on inverter, so 10ga on the output of the inverter/charger to the main breaker panel input puts everything covered to the panel, which feeds the entire van through the appropriate sized breakers which I changed to all GFCI breakers to be safer and make it possible to get rid of the troublesome GGCI outlets we had.


On systems with smaller inverter/chargers, if you want all the outlets to work on inverter or shore/genny power, you would tap off the above diagram system as shown, but you would need to make sure you used a 30 amp second transfer switch and the unit should have breakers to protect the charger section built in. If it is a standalone charger use an inline breaker to the charger. That way you can still run the output of the second transfer switch to the main panel and use all the normal breakers for both inverter and shore/genny power.

[Jim McGuire Nue-Era]

Originally Posted by avanti

Ah. Good point.

OTOH:
Couldn't you have also simply connected the charger upstream of inverter (i.e., between the output of the external transfer switch and the input to the inverter?

Tried to send this hope it makes some sense. I did not want Air conditioning on inverter or other heavy load so I wired to the inverter AC outlet w/ground fault and 15 amp fused circuit.
The load shed device limits where the current will go hot water or microwave but not both at same time (microwave priority).

[MobileCabin]

I looked at the WB site because the name of the OP and found a lot of wiring diagrams:

https://www.winnebagoind.com/diagram...ing_Models.htm

I like all the info they provide. Can't say that is the case for other brands.

[pbellist]

I have a Pleasure-Way Excel with an Iota Engineering TS30 Transfer Switch and a Progressive Dynamics PD9140A Converter. The transfer switch has the generator connected to one input, shore power to the other input, and the output connected to the AC bus bar to which the converter is connected.
As previously described by someone else, I’m thinking to add an inverter to the system by adding a second automatic transfer switch with the output of the first switch connected to an input of the second switch, the inverter connected to the other input of the second switch and the output of the second switch connected to the AC bus bar, thereby automatically switching between the 3 power sources.
However, my understanding is, when on inverter power, there would be issues with the inverter powering the converter, the converter charging the house batteries, and the house batteries powering the inverter, thereby creating a loop. If so, what would be a good way to eliminate that problem and still have automatic switching?

[booster]

Originally Posted by pbellist

I have a Pleasure-Way Excel with an Iota Engineering TS30 Transfer Switch and a Progressive Dynamics PD9140A Converter. The transfer switch has the generator connected to one input, shore power to the other input, and the output connected to the AC bus bar to which the converter is connected.
As previously described by someone else, I’m thinking to add an inverter to the system by adding a second automatic transfer switch with the output of the first switch connected to an input of the second switch, the inverter connected to the other input of the second switch and the output of the second switch connected to the AC bus bar, thereby automatically switching between the 3 power sources.
However, my understanding is, when on inverter power, there would be issues with the inverter powering the converter, the converter charging the house batteries, and the house batteries powering the inverter, thereby creating a loop. If so, what would be a good way to eliminate that problem and still have automatic switching?

I think you are OK if I read it correctly as long as you take the charger off the coach wiring.



Shore and gen into 1st transfer switch.


Output of 1st transfer switch to charger only with add on breaker and also to input of 2nd transfer switch priority side input.


Output from second transfer switch to coach only.


You would need to run a new 120v wire from the 1st transfer switch to charger/breaker and disconnect the one in the breaker box. If the breaker box is more convenient, you may be able to run to box and do the charger connection change there with a new wire.


This will not get rid of the chance of the inverter running at the same time as shore or genny on, but it will disconnect it so it won't supply any power.


There is one issue that might be a problem depending on the inverter and the transfer switch. You can't just run a single wire 110v to the charger and use the existing neutral and ground. You need all 3 at the transfer switch for each of the sources independently so they all will get switched together for that source. This eliminates problems like double neutral to ground bonding issues.

[hbn7hj]

Originally Posted by pbellist

I have a Pleasure-Way Excel with an Iota Engineering TS30 Transfer Switch and a Progressive Dynamics PD9140A Converter. The transfer switch has the generator connected to one input, shore power to the other input, and the output connected to the AC bus bar to which the converter is connected.
As previously described by someone else, I’m thinking to add an inverter to the system by adding a second automatic transfer switch with the output of the first switch connected to an input of the second switch, the inverter connected to the other input of the second switch and the output of the second switch connected to the AC bus bar, thereby automatically switching between the 3 power sources.
However, my understanding is, when on inverter power, there would be issues with the inverter powering the converter, the converter charging the house batteries, and the house batteries powering the inverter, thereby creating a loop. If so, what would be a good way to eliminate that problem and still have automatic switching?

I just turn the breaker for the converter off when the inverter is on. I am very rarely on shore power and chargers are manually operated so the converter stays off.

[Road Toad]

We did what the OP is wanting by adding a second Manual transfer sw after the Existing automatic transfer sw. (Inverter did not have an internal xfer Sw)
Existing sw decides shore vs Gen; 2nd sw decides inverter output or 1st sw output. A bit inconvienient but very inexpensive.
Cost about $15

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Originally Posted by booster

First part, that is just what I am saying to do two transfer switches. First one shore/genny, second one is output of first one/ inverter.


Second part I don't get. A standalone inverter with a transfer switch is primarily a DC device that changes power to AC output, so I supposed you could call it half and half if you want. The AC input to an inverter without charger is just passed through the inverter so you really have two AC inputs to the internal transfer switch, one from the DC generated inverter section internal to the unit, and one from some other AC source. I don't get how you are going to get 3 independent AC sources (shore, genny, inverted) that way, unless the AC input to the inverter is the output of another transfer switch with two inputs.


Time to sketch the diagram

[Road Toad]

+1 ... What he said.

Originally Posted by booster

I think you are OK if I read it correctly as long as you take the charger off the coach wiring.



Shore and gen into 1st transfer switch.


Output of 1st transfer switch to charger only with add on breaker and also to input of 2nd transfer switch priority side input.


Output from second transfer switch to coach only.


You would need to run a new 120v wire from the 1st transfer switch to charger/breaker and disconnect the one in the breaker box. If the breaker box is more convenient, you may be able to run to box and do the charger connection change there with a new wire.


This will not get rid of the chance of the inverter running at the same time as shore or genny on, but it will disconnect it so it won't supply any power.


There is one issue that might be a problem depending on the inverter and the transfer switch. You can't just run a single wire 110v to the charger and use the existing neutral and ground. You need all 3 at the transfer switch for each of the sources independently so they all will get switched together for that source. This eliminates problems like double neutral to ground bonding issues.

[Road Toad]

OR ... Here is an inexpensive auto xfer sw for 2nd inline unit ...
https://www.amazon.com/Go-Power-TS-3...l%2C170&sr=8-7

[Road Toad]

We fed the Converter/charger Ckt Breaker with an input from the Shore/gen transfer sw output thus the Inverter output does not feed the Converter ckt.
Ergo, no "loop" issue. (No self insemnation this way )

Originally Posted by pbellist

I have a Pleasure-Way Excel with an Iota Engineering TS30 Transfer Switch and a Progressive Dynamics PD9140A Converter. The transfer switch has the generator connected to one input, shore power to the other input, and the output connected to the AC bus bar to which the converter is connected.
As previously described by someone else, I’m thinking to add an inverter to the system by adding a second automatic transfer switch with the output of the first switch connected to an input of the second switch, the inverter connected to the other input of the second switch and the output of the second switch connected to the AC bus bar, thereby automatically switching between the 3 power sources.
However, my understanding is, when on inverter power, there would be issues with the inverter powering the converter, the converter charging the house batteries, and the house batteries powering the inverter, thereby creating a loop. If so, what would be a good way to eliminate that problem and still have automatic switching?

[Bud]

Originally Posted by RoadToad@live.com

OR ... Here is an inexpensive auto xfer sw for 2nd inline unit ...
https://www.amazon.com/Go-Power-TS-3...l%2C170&sr=8-7

Less yet:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[Road Toad]

Yes, but it is only a 15 amp unit.
The GoPower is 30 amp.

[Road Toad]

Hey Booster.. Good stuff..
One question though:
Why do we want "... to input of 2nd transfer switch priority side input..."

If we send inverter to priority in 2nd xfer, wouldn't that leave us on inverter until Shore or Gen hit it and thus use less energy keeping the coil relaxed instead of drawing current during Inverter use?

[booster]

Originally Posted by RoadToad@live.com

Hey Booster.. Good stuff..
One question though:
Why do we want "... to input of 2nd transfer switch priority side input..."

If we send inverter to priority in 2nd xfer, wouldn't that leave us on inverter until Shore or Gen hit it and thus use less energy keeping the coil relaxed instead of drawing current during Inverter use?

Assuming the terminology means that if both are on, then priority is the one that will supply the power. In this case the output from transfer switch one would be shore power or generator, and you would want either of them to carry the load if available, not the inverter. Strictly an order priority. On the first switch, shore power would have priority over the generator.

[Road Toad]

I think maybe I am screwed up on "priority".
.

To me that is the unenergized( N.C.) position of the Relay.
And the switched (energized) (N.O.) closes when the "secondary" input becomes hot.
Is this what you mean?

By this measure, I would want the Gen to be Priority in the 1st Sw, and Inverter to be Priority in the 2nd Sw.
Thusly, the Inverter would "present" if no other input hot.
And Shore or Gen would "present" if either is running.
??
(I think maybe I'm back wards in definition?)

[Road Toad]

Yeah, pretty sure I am backwards.
Seeing as how if both sources into the Sw are hot, the relay would pull in and present the N.O. set; that would make sence that the N.O. is "Priority"
Ehh?

[booster]

Originally Posted by RoadToad@live.com

I think maybe I am screwed up on "priority".
.

To me that is the unenergized( N.C.) position of the Relay.
And the switched (energized) (N.O.) closes when the "secondary" input becomes hot.
Is this what you mean?

By this measure, I would want the Gen to be Priority in the 1st Sw, and Inverter to be Priority in the 2nd Sw.
Thusly, the Inverter would "present" if no other input hot.
And Shore or Gen would "present" if either is running.
??
(I think maybe I'm back wards in definition?)

I just looked at the wiring for Progressive Dynamics switch and description. They want shore power on what appears to be normally closed and generator on normally open and have them marked that way. It said generator overrides shore power.


So if you have the second switch with the inverter on the normally open it should be impossible to have inverter and the other sources running to coach AC at the same time. But, you could wind up with shore power or generator running the charger at the same time as inverter is running if you forgot the inverter on. That in itself is not an issue except a waste of running the charger and being limited to the AC power of the inverter which will override the other sources and maybe kill the batteries over time. It would also give the possibility of having two neutral to ground bonds connected through the chassis ground which is not good.


I think the only way around the ground and neutral bond thing would be to shut off the 12v power to the inverter if either of the other sources were on so the inverter would stay unbonded when on any other source. It could be done with a relay as mentioned by another poster earlier.


If you find a 3 way transfer switch it would take care of all that for you. I think.

[Road Toad]

Thanks for the help.
Good to go. The relay thing is great idea; AND just happens to fit in brilliantly with my inverter design. It is a Wagan and has a "remote switch" port. The aforementioned relay can be energized with the Shore/Gen output and open the relay contacts and shutoff the Inverter.
Think will let Gen be 1st Xfer boss and Inverter not 2nd Xfer boss.
Inverter won't even power up if either other source is hot.