Wiring your inverter back to the main breaker panel

[whybother]

Originally Posted by gsgriffin

Does this make sense to everyone? Any problems with this concept you can think of?

For an automatic solution that should stay within the ballpark of your ~$100 budget, how about:

1. A large enough junction box.

2. Three 110V/120V transfer switches / large DPDT relays, one for each leg of your 50a service plus another to control power to the inverter.

3. A little 10AWG and 12AWG NM wire and NM clamps for making the connections.

Put 2 of the relays between your existing transfer switch and the main panel. Power the coils on the relays from each leg of the output from the main transfer switch and also run through the N/O contact terminals. Have the inverter AC output tied into both the N/C contact terminals on the relays. Have the output of the relays run to the main panel.

For the third relay, power the coil off either of the legs from your 50amp service. Route the inverter line from the main panel through the N/O contact, then out on to the inverter. (N/C contacts on third relay left unused.)

[gsgriffin]

Originally Posted by whybother

For an automatic solution that should stay within the ballpark of your ~$100 budget, how about:

1. A large enough junction box.

2. Three 110V/120V transfer switches / large DPDT relays, one for each leg of your 50a service plus another to control power to the inverter.

3. A little 10AWG and 12AWG NM wire and NM clamps for making the connections.

Put 2 of the relays between your existing transfer switch and the main panel. Power the coils on the relays from each leg of the output from the main transfer switch and also run through the N/O contact terminals. Have the inverter AC output tied into both the N/C contact terminals on the relays. Have the output of the relays run to the main panel.

For the third relay, power the coil off either of the legs from your 50amp service. Route the inverter line from the main panel through the N/O contact, then out on to the inverter. (N/C contacts on third relay left unused.)

I will only go through the huge hassle of a new box if I can't fit this. That will be an ordeal.

You are suggesting switches and then also relays. I'm curious. Why would doing switches and then adding relays be better than a single switch that has the capacity and ability to do the switching and can ensure that circuits remain isolated? Seems like an additional point or two of failure for no functional benefit with relays.

[whybother]

Originally Posted by gsgriffin

You are suggesting switches and then also relays. .

No, just 3 DPDT power relays to act as an automatic transfer switch for your inverter instead of a manual rotary switch. Two relays to switch between shore/generator and inverter and one to shut of the AC input into your inverter when running on inverter. You could probably get away with a cheaper/smaller/SPST relay for controlling the hot AC input to your inverter. (Or you could just buy an off-the-shelf 50A transfer switch, plus another relay, though that'll probably cost a bit more.)

Originally Posted by gsgriffin

I will only go through the huge hassle of a new box if I can't fit this. That will be an ordeal.

If you're able to cram the manual rotary switch with all the wiring inside your existing main panel without going way over its capacity, then yes, that would be a bit easier. I was under the apparently wrong assumption that you'd be mounting that in a new external box, between your existing ATS and main panel -- thinking; if you're going to go through that hassle anyway, make it automatic.

[HarryStone]

Man, that is a hassle to do. Your inverter 'should' have a built in transfer switch, why not use it?

[whybother]

Originally Posted by HarryStone

Man, that is a hassle to do. Your inverter 'should' have a built in transfer switch, why not use it?

Guess I just assumed his didn't have a transfer switch capable of switching a 50a service, else he would have used it.

[Rockies]

Originally Posted by gsgriffin

. . . there were folks stating that it couldn't be done or running the AC wasn't going to happen . . .

We easily run our Micro Air Easy Start equipped 11k BTU a/c in our truck camper with a DIY 200ah LifePo4 battery pack (w/200a BMS) using an inexpensive Aims 2000w high-frequency inverter. Get about 90-100 min of compressor runtime before we hit ~15% SOC. Our a/c only takes 5 min. to make a noticeable difference in comfort, so well worth running when we take 15-30 min. breaks while traveling. When we get back on the road, we use a dc to dc charger to recharge the battery in time for our next break.

[gsgriffin]

Originally Posted by HarryStone

Man, that is a hassle to do. Your inverter 'should' have a built in transfer switch, why not use it?

My inverter does have a transfer switch. Also automatic with the generator and shore.

Sorry if I didn't explain this properly from the start. I would guess that most every Monaco (like mine) has a good inverter, generator and automatic switching (which I can turn on/off/auto with a button on the inside controller as well as charge time during the day to get low-rate hours, auto-start generator, etc....)

The change I am making is the output of the inverter, which by design powers the microwave and outlets....TV, rear bathroom, middle bathroom, etc...What I wanted the option of is using up the solar power with anything else that can use it and not have to hot-wire things back to outlets....so I'm taking the output of the inverter and routing back to the main input breaker for the main breaker panel. At the same time, ensuring the power source from the breaker to the inverter is disconnected. Now, if I wanted to heat the water, block heat the engine in a cold morning before leaving, even run the fridge or AC for short while, I have that option and ability.

Looking at a simple switch. I don't think I want it automatic, but will look into the options. When multiple relays are used and required to respond at the same moment, it might always give me the fear that if one fails and doesn't repond, it would then causes catastrophic failure.

[whybother]

Originally Posted by gsgriffin

My inverter does have a transfer switch.

If your inverter has a 50a/60a transfer switch (can switch both legs), then easiest thing to do would be to simply run the output from the shore/generator transfer switch directly to the inverter, then the inverter's AC output directly on to your main panel, abandoning the separate inverter feed for your microwave, etc.

If your inverter only has a 30a transfer switch (only supports a single leg) then you'd need to switch by other means, like you're planning.

Originally Posted by gsgriffin

it might always give me the fear that if one fails and doesn't repond, it would then causes catastrophic failure.

Yeah, it would be better to use a single 4PDT relay, but suitable ones that can take the inductive load of an A/C can be difficult to track down -- so you'd probably just want to use an off-the-shelf 50A transfer switch, plus another relay for controlling input to the inverter.