AC / DC - need trailer wiring solution done dirt cheap

I'm looking to leverage multiple power input sources for my enclosed trailer.

There's plenty of good information regarding trailer lighting and wiring on the beeb. Still, I didn't find a solution for my KISS approach. Basically a power line, inline fuse and minimal wiring is what I seek. Unless the solution I seek presents a fire hazard or risks damage to my tow vehicle, I'd like to keep it all simple and my trailer interior walls uncluttered.

Any feedback is appreciated.

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Power input sources:

1. Battery
2. Shore power (use AC-DC converter)
3. Generator (use AC-DC converter)

My requirements:

a) Up to 30Amps (10Amp requirement for LED strip lighting)
b) Quick selection of power input source
c) Full-service charger for a battery
d) Use for lighting mainly (but sometimes I'll use a power tool--dremel, power drill)

Some pics:

Pic 1 - AC port plug
Pic 2 - AC-DC converter
Pic 3 - Charger
Pic for battery not included but assume I will have one

The charger (pic 3) comes to mind because, with a quick mod to the included male/female connectors, I can switch the connectors and use either of the DC or AC power input sources.

 

That setup may work, and it will be cheap. It won't be reliable.
Some questions and observations:

I'm assuming that the 30A is at 12V, not 120V. To make 30A at 120V (3600VA) from 12V will require a 3500VA or larger inverter and batteries that can produce ~340A @12V continuously.

That port is a standard 15A plug under the cover. In about 6 months of regular use, it will get loose, and it will be hard to keep the cord connected to it. I recommend a twist-lock input port, either 15 or 20A 120V. It will never wear out. Adds cost and significantly improves reliability.

Think about how you are going to keep that wiring safe from the rubbing and catching of stuff in the trailer. Come up with a plan to enclose it in conduit or something. If you put the wiring behind the walls, protect it from vibrations, rubbing on the metal struts/frame, etc. Stranded wiring, rather than Romex or other solid wire is strongly recommended.

Changeover - auto or manual? Manual is straight forward, get a Blue Sea maritime A-B-Off switch. Auto - you will need diodes and heat sinks, or an isolator.
If you have a 7-pin trailer power connection, and aren't using the trailer brake battery and charger, you can pull 20-30A from the Aux power connection on the trailer light connector - when the tow vehicle engine is running.

Charging - what is your plan for ventilation when charging the battery? If the battery is inside the trailer, a charge from deep discharge will release a not-insignificant amount of hydrogen. Also, that is a 2A charger, and won't fully recharge a run-down battery of modestly decent size (70-100AH) in a day on the generator at the track. Again, look into marine automatic battery chargers and deep-cycle marine/RV type batteries.

What is the extra 20A at 12V for? If you are planning on an inverter, remember that 20A at 12V is about 1.6A at 120V after inverter losses and before power factor. If you are planning on an inverter other than a 100-150W type, a much heavier wiring and charging system will be necessary. If you want to use electronics, a sine-wave inverter is strongly recommended. The cheap inverters are stepped square wave, and anything with a linear power supply will not like it at all.

If you keep it to only powering the LED lighting, your plan may very well work out running the LED's from either the power supply or the battery with an A-B-Off switch. With any additional load, your plan is likely to produce insufficient results.

Remember for battery sizing, that its all about Amp-Hours. A 12V - 10A load for 1 hr is 10 AH. Calculate your power need and purchase a battery that will provide sufficient power.

 

Yes. That's correct. 30A isn't an immediate need though other than planning for future demands.

Thanks. It will get used a lot so that's helpful to know.

Definitely manual. I'm keeping this as simple as possible.

I have someone who offered to spec out an electrical component and I'll retain this advice as extra input.

Thanks.

 

@beac83 for the win!!