The Dreaded Trailer Electrical Dilemma

You are on the right track because you know what you want. And I don't think you will be disappointed or have any regrets. It think the biggest dilemma is deciding on a power supply/battery charger/converter setup or no converter, drawing directly from battery, which I don't recommend because your protected by fuses with a converter (just my opinion, nothing expert or official about that thought) And you will have many opinions on the combo or separate converter/charger here.

I have a single unit for the 30 amp power supply/charger/converter. My battery charges from my vehicle (7 pin connector required) when traveling. When plugged into shore power, my battery charges from shore power through the charger and my 12v (lights and fan) are drawing from converted 110 power, therefore I can use both 110 and 12v lights and fan. When boondocking, my 12v is drawing from the battery and 110 lights, outlets are not available (most don't understand this part; it takes an inverter to accomplish that). Boondocking, I have 12v lights and fan, propane stove and icebox (lucky ones have the propane fridge) and it's quite efficient. I also have a 12v plug outlet and usb outlet combo which I haven't installed yet.

My personal trailer will have no 12 volt or propane. Like you I have no plans for resale. It is being built for the personal use of the boss and I. I will have 30 Amp 110 and AAA battery powered led lights as needed. You can buy a huge amount of AAAs for what one 12 volt deep cycle cost plus no charger cost or maintenance. My thoughts are that when we are done with it I will sell it for what ever someone will pay, and then smile. Over the last 50+ years I have bought and sold many RVs and when it is all said and done I never made much profit except for the enjoyment they brought us. If you want to make a profit off of trailers repair them for others. Most guys who said they made a big profit on a trailer either sold lipstick on a pig or they only paid themselves fifty cents an hour for their labor. My reason for having a trailer is having my own bed, no carrying luggage in to a hotel and no bringing bed bugs out. Also I have met some of the greatest people in the world while camping. I hear people say the have a camper to save on hotel cost, but if they figured the cost of buying, maintaining, insuring, the extra fuel to tow, and wear and tear on the tow vehicle they might be breaking even. The very best thing about camping is the total experience in God's great outdoors, many of our best memories are of things we did and saw while camping.

It seems you have pretty well nailed down how your end results will best serve your needs. That really is the most important first step.

I did some additions already to my recent project, and added a 12-volt converter to the system.   This worked for this trailer, but is admittedly not the way I would go if I were doing a re-build.

vintagetrailertalk.freeforums.net/thread/3718/converter-pc-201-plus-volt?page=1

It is wired from the 15-amp panel and runs all the 12-v lights (eventually water pump also) when plugged to shore power and maintains the onboard battery. The battery takes over when unplugged, so that the 12-V system still lights up when not plugged. This installation meant running some new wiring for the feed from the breaker box, and for the 12-volt items I had added, which really only has amounted to a couple cigar-lighter-type plugs. I managed to tie into the old setup on mine and not disrupt the setup too much. It is no longer hooked up to charge from the tow vehicle, but could be switched back in the future if necessary.

Also, I rewired with a 30-amp cord leading into the box. I have yet to change to box out to a 30-amp service, but intend to do so along the way. I'm not changing any of the trailer's wiring, as it stands, but putting a 2-breaker box in will allow the converter its own breaker and separate the 12-v from the other outlets, as well as flexibility to add another outlet if we put any more equipment in.

The Airflyte will be a bit different story. Its original setup is exactly like yours. As much as I strive to keep to the original, I do believe I may change out the wiring for 12-ga copper throughout, and will upgrade to the 30-amp box. It may never need it, but the option to add a dedicated circuit later if we decide we need an air conditioner in our older age is a nice option. I might use the combo panel and add a couple 12-V leads as well, for a light in the cargo compartment and some lighter plugs for the cell phones, etc. I too am planning to keep the original single light with the lead for its own battery in the cabinet.

I love the idea of keeping to original, but then the thought behind adding options enough to cover possible future considerations, like easier boondocking if life takes us in that direction, just make sense to me. It means a bit more planning and dreaming and expense, but the time to do it is while it is apart.

Damn, I had forgotten about my 12 volt Fan-Tastic Fan! Looks like I either need a converter to take 110 to 12volt just for the fan or build a simple recharging 12 volt system.

If I did build a simple 12 volt system, how long could the fan operate on a standard deep cycle sealed battery or golf cart battery without recharge?

I just run all lighting and fans on 12vdc. I disable the little two slot 110vac outlets in the lamp bases. Then I install a converter that I get from VTS, one or two 12v deep cycle batteries and use the old AC wiring for DC. Put 12vdc incandescent bulbs in place of the 110vac ones and all the lights light up. Then I run one or two new 110vac outlets on the same circuit that runs the converter. If you can use the old holes go ahead and do it. I also like to install a place for charging. You can buy a little panel for that which has 5vdc usb ports in them. You can also get cig lighter outlets. If you have AC then of course you will want another designated circuit for that. Generally a 30 amp service will handle everything. two breakers. one 10 amp and one 20 for the AC if it's a window unit.

Ever heard of a gas powered blender?