Is Plug-in Solar Feasible for a T@B?

RTWCTS · January 4

Recently I've seen a few articles/videos on plug-in solar. The basic concept is that solar panels attach to a microinverter (converting the voltage to 120V AC). The electricity then passes through a plug and into a standard 120V outlet. This feeds the loads in a 120V circuit. It appears to be quite popular in Europe. According to a segment on PBS (link below), Utah recently made it legal for home use and legislation has been introduced in other states.

Small plug-in solar panels gain traction as an affordable way to cut electricity bills | PBS News Weekend

Could this work as a plug and play solution to augment power in a T@B through the outside receptacle? Would it power the converter to charge batteries? Let me know your thoughts...

Grumpy_G · January 4

It's meant to save on energy bills, which you (typically) don't have in a trailer. You can just as well charge the trailer battery directly via solar and avoid the losses from converting into 120V AC and then back into 12V.

pthomas745 · January 4

When I read up about these, I thought right off it would be a very easy way to install batteries under the benches of my 320, with a simple inverter setup. The plug in solar would take care of charging the batteries and running an inverter...with very little extra wiring involving the trailer's WFCO.

SLJ · January 4

For a camper I would think running a solar panel through a microinverter and then dropping it back to DC voltage to charge the battery would be very inefficient.

Marceline · January 5

RTWCTS said:

Could this work as a plug and play solution to augment power in a T@B through the outside receptacle? Would it power the converter to charge batteries? Let me know your thoughts...

It's an interesting idea that could allow you to use the AC circuits when boondocking. But doesn't your 400 already have a built-in inverter that allows the same from your roof solar?

RTWCTS · January 7

Thinking back to our old 320 that came with no solar (or inverter), this just seemed to be a stupidly simple way to get AC power into the trailer. Wasn't sure about it powering the WFCO converter to recharge the battery in this 'mind exercise' though.
To be sure, we don't need to add this plug-in concept to our 400. The factory rooftop solar and our briefcase panels can keep us energized long term while dry camping. Our only (electrical) shortcoming was keeping cool in the summer. We solved that when we bought our Silverado EV. Now on hot days we just plug the T@B into the 30A outlet in the bed of the truck and have AC power to spare.
Guess I'm just suffering cabin fever right now... c'mon warmer weather!

Grumpy_G · January 7

It just occurred to me that this isn't going to work. For safety reasons these microinverters do not turn on their output unless they detect AC voltage present in the socket. Otherwise voltage wold be present at the exposed blades of the plug, and the system would backfeed in case of a power outage or a tripped breaker. The trailer wouldn't have AC present unless running off a built-in inverter or connected to shore power.

RTWCTS · January 7

... and that's why I asked the question. Thanks @Grumpy_G!

ckjs · January 7

Grumpy_G said:

It just occurred to me that this isn't going to work. For safety reasons these microinverters do not turn on their output unless they detect AC voltage present in the socket. ...

[Edit: I've had residential solar on the brain recently. The following is mostly about USA microinverters designed for 240V solar installations connected to a utility company's service. ]

Adding in agreement: these are "grid-following" devices, which match their voltage level and phases to the circuits they're plugged into. The main safety reason is to prevent feeding into the grid when there could be utility workers touching the presumably dead lines.

There are "grid-forming" 240V devices designed for off-grid and backup of grid-tied applications; they have extra electronics. They cost more, and are hard or impossible to find at the moment for end-user mobile and RV 120V applications.

RTWCTS · January 7

ckjs said:

Adding in agreement: these are "grid-following" devices, which match their voltage level and phases to the circuits they're plugged into. The main safety reason is to prevent feeding into the grid when there could be utility workers touching the presumably dead lines.

There are "grid-forming" devices designed for off-grid applications; they have extra electronics. They cost more, and are hard or impossible to find at the moment for end-user applications.

Here is a recent article from DW that seems to dispute some of your comment.
Cheaper, cleaner energy drives Germany's balcony-solar boom – DW – 12/18/2025

They seem to be, in fact, for grid tie systems and are used frequently in Germany. I do believe reading that they have built-in protection to keep them feeding back into the grid (but would have to search for confirmation saying so).
With them being legal in Utah and under consideration in other states (see link in my original post), it just got me thinking about potential uses. That was why I asked the original question. No harm or foul if it doesn't work in a trailer. This is just a cool concept I was learning about while stuck indoors.

ckjs · January 8

@RTWCTS: In Europe some things are easier, because their 220/230V don't have to deal with our split 120 phases in opposition coming from the power pole. Those complications inspired my previous semi-off-topic post. I'd never seen mentions of 120V microinverters before, and it sent me down the wrong rabbit hole.

I'm glad that "balcony solar" has gotten clearance in Utah. We already have PV at home. An plug-in addition could be useful, if priced right. However, for a camper, one of those "solar batteries" which includes an inverter would probably cost less.

@Grumpy_G mentioned the danger of the exposed blades of the plugs. That's a real risk: the wiring for a generator to plug into your house (plugs at both ends of an extension cord) is called a "suicide cord" for good reason.

RTWCTS · January 8

ckjs said:

@RTWCTS: In Europe some things are easier, because their 220/230V don't have to deal with our split 120 phases in opposition coming from the power pole. Those complications inspired my previous semi-off-topic post. I'd never seen mentions of 120V microinverters before, and it sent me down the wrong rabbit hole.

I'm glad that "balcony solar" has gotten clearance in Utah. We already have PV at home. An plug-in addition could be useful, if priced right. However, for a camper, one of those "solar batteries" which includes an inverter would probably cost less.

@Grumpy_G mentioned the danger of the exposed blades of the plugs. That's a real risk: the wiring for a generator to plug into your house (plugs at both ends of an extension cord) is called a "suicide cord" for good reason.

Using the info from the last post by @Grumpy_G, I was able to craft better search query. This is a synopsis from the Utah legislation:

Key Features of H.B. 340

Definition and Specifications

Portable Solar Generation Device: Defined as a movable photovoltaic system.
Power Output: Maximum of 1,200 watts.
Connection: Must connect to a standard 120-volt outlet.
Safety Features: Must include anti-islanding protection to prevent energizing the electrical system during a power outage.

The fourth bullet point is why plug-in solar won't work in a trailer. Also, the are no energized blades in the plug (no "suicide cord" capability) until after it connects and detects voltage present.
My (limited) understanding of generators and house wiring is NEC requires a transfer switch. The main power has to be turned off for the transfer switch to be activated and allow generator power into the house lines. If the generator is off and transfer switch engaged when plugging a generator in to the transfer switch, I don't understand how you can be shocked as there is no electricity source.

Ultimately though, plug-in solar is not a solution for powering a trailer while dry camping. Thanks for the insight!

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Is Plug-in Solar Feasible for a T@B?

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Key Features of H.B. 340

Definition and Specifications