Do I need an ATS?

[PlanetExcellent]

Planning a future installation in my travel trailer. Thinking 4x 100watt panels, 2x 100ah lithium batteries, 2000 watt inverter/charger.

I'm confused about whether I need an auto transfer switch. If I'm plugged into 30A shore power, I wouldn't turn on the inverter. If I turn on the inverter, it's because I'm not connected to shore power. I'm trying to imagine how I would ever wind up with the inverter on AND shore power connected and possibly overload my AC panel. Even if that's a real possibility/risk, wouldn't a manual transfer switch work just as well for less money?

What am I missing?

 

[John Frum]

Planning a future installation in my travel trailer. Thinking 4x 100watt panels, 2x 100ah lithium batteries, 2000 watt inverter/charger.

I'm confused about whether I need an auto transfer switch. If I'm plugged into 30A shore power, I wouldn't turn on the inverter. If I turn on the inverter, it's because I'm not connected to shore power. I'm trying to imagine how I would ever wind up with the inverter on AND shore power connected and possibly overload my AC panel. Even if that's a real possibility/risk, wouldn't a manual transfer switch work just as well for less money?

What am I missing?

Inverter/chargers generally include an automatic transfer switch.
Please provide a product link so that we can verify.

 

[PlanetExcellent]

I haven't decided on an inverter yet. I'm considering something more basic like a Giandel 2200W without ATS, or a more sophisticated inverter/charger like Spartan Power or AIMS 2500W with ATS. I really want one with an integrated charger, but the ATS doesn't seem like it adds any value for me. I would love a Samlex EVO 2212 but that's over my budget; I'd like to stay under $700.

 

[eabyrd]

Planning a future installation in my travel trailer. Thinking 4x 100watt panels, 2x 100ah lithium batteries, 2000 watt inverter/charger.

I'm confused about whether I need an auto transfer switch. If I'm plugged into 30A shore power, I wouldn't turn on the inverter. If I turn on the inverter, it's because I'm not connected to shore power. I'm trying to imagine how I would ever wind up with the inverter on AND shore power connected and possibly overload my AC panel. Even if that's a real possibility/risk, wouldn't a manual transfer switch work just as well for less money?

What am I missing?

I don't think you're missing anything, the difference is convenience and automation. If you aren't looking for a UPS type failover capacity then getting up and flipping the switch yourself is fine. The automatic switch I used (and I would have to lookup the name / model) was setup so that when you started the Genset it waited for a period of time until the flow settled before making the switch from shore to the Genset (if the grid was up. Same in reverse, if you were running on the Genset and it sensed the grid it would wait to make sure it stayed there before switching back and taking the load off the genset. I had my inverter charger downstream from the ATS, and my SCC was separate from the inverter charger. That allowed me the ability to have a back-up battery charger based on either shore power or generator power. I just realized both the inputs on my quick dirty little diagram are labeled shore power, one should be labeled Generator... DOH

 

[John Frum]

I haven't decided on an inverter yet. I'm considering something more basic like a Giandel 2200W without ATS, or a more sophisticated inverter/charger like Spartan Power or AIMS 2500W with ATS. I really want one with an integrated charger, but the ATS doesn't seem like it adds any value for me. I would love a Samlex EVO 2212 but that's over my budget; I'd like to stay under $700.

These inverters have an ATS but don't have a charger.

Pure sine wave inverters with built-in transfer switches | DonRowe.com

Backup your sensitive electronics with a pure sine wave inverter that has an automatic transfer relay built-in. The relay allows for incoming AC power and automatically takes over with pure sine wave when the incoming AC is no longer available.

www.donrowe.com

I looked at your posting history and you asked about integration issues between the inverter and the converter.
The simple explanation is to connect the converter in parallel to the inverter on the ac side.
That means both use shore power when available and the converter does not power loop with the inverter.
I can explain in more detail if you are interested.

Depending on the inverter the ATS may synchronize the inverter to the mains power so that your loads don't even know the transfer occurred.
That is impossible with discrete transfer switches.

 

[HRTKD]

I'm not the only occupant in my trailer. Every design decision starts with that in mind. If I have to write out instructions for my wife, there's going to be a problem. She's a retired system analyst and no dummy. But she's there to relax, not get technical.

There is no way I would put in an inverter that doesn't understand how to handle shore power. Don't tell my wife this, but I built the system to be idiot proof.

 

[time2roll]

If the inverter is to be wired in you need a transfer switch in an RV.

If you plan to plug the main cord into the inverter then you are the transfer switch and this works fine. Otherwise you need some extension cords to power things direct from the inverter.

And don't even think about a suicide cord to just insert power into one of the outlets.