Hi. First time post. Nice to meet you all.My wife and I just bought a 1965 Shasta Compact travel trailer. The trailer is already wired for shore power (AC) and that system is working fine. When we plug in from the house we can power the trailer. At the moment we have 4 light fixtures and 8 outlets. We removed all of the appliances and don't plan on running anything that needs more power than light fixtures and small appliances (radio, 300 watt kettle, small fan) that we will occasionally plug in when needed.I started to install our 12V batteries (2 deep cycle marine batteries) yesterday and realize that I am missing a piece of the puzzle. My dilemma is that I don’t know how to connect the DC system to the existing AC system. We are not running any DC appliances or lights so I need the DC battery system to connect directly to my existing 110V AC system. I am assuming that I need an inverter, but I don't know how to connect it to the AC system since usually they just have a few outlets in the front for plugging in appliances. Is there an adapter that would go from the inverter outlet to my junction box or panel?Does anyone know the best way to go about this?

You need a converter, it will change the 110V AC to 12V DC. It will also keep your batteries charged.

Back in that era, even some light fixtures used what appear the same as 120 vac bulbs, but were in fact 12 volt. If you are happy with the 120 vac setup, I'd suggest your two batteries and an inverter, likely a 1500 watt model and locate its output where you could physically plug the campers power cord into the inverter when you want it to power everything inside. you would then unplug it to plug into shore, eliminating the possibility of crossing power sources. you will have to carry a separate battery charger plugged in from outside source when you want to charge batteries.

I would politely suggest that you double check what your interior lights run on. I would be surprised if they were 110V AC.The normal configuration is 110V AC shore power ===> Converter ===> 12V DC to everything the trailer is equipped with (lights and appliances).Have you tested the lights or checked stickers inside the fixtures to confirm they are 110V AC?

I did check the fixtures and they are 110V. It appears that a previous owner rewired the entire trailer to run on 110V. Apparently doing away with any DC fixture. Or perhaps in 1965 they weren't using battery power at all because the trailer also had an installed gas lamp:-)As far an an inverter goes, is there possibly an adapter that could connect from the inverter outlet right into my panel or junction box? The shore power is actually an inlet not an outlet, so the female side of the extension cord from the house plugs into a male receptor on the trailers exterior.

Enjoy the read.....great info YOU will need12V Side of Life

Battery (DC) to Shore Power Wiring | Good Sam Community

16 Replies

Harvey51
Explorer
Jun 27, 2017
Hi jnagy, I'm a 25 year veteran of pop ups, now camping in a small motorhome.
Our popups only had one or two lights, (12 volts) and the later 1992 one had a heater and converter. We used a portable booster battery to power the popup and charged it in our van while travelling. We never plugged in to 120 volts and used propane to boil our kettle. The modest use of electricity enabled us to camp for extended periods in remote areas.

If you want to go boondocking you would probably find it beneficial to change your lights back to 12 volt LED lights to eliminate the inverter. An inverter producing 1500 watts of AC would draw 150 amps from the batteries, if they are able to supply that much, and require some very heavy wiring. Boiling the kettle that way would mean hours of battery charging.

We now have a 100 watt solar panel that keeps our batteries charged all the time. No generator and no shore power needed.
westend
Explorer
Jun 27, 2017
I have a '71 trailer so not that much newer but in that era , there was the beginnings of onboard 12V converters. My '71 Progressive Industries converter has an optional circuit board to enable the 12V power supply to become a battery charger, for example. In any instance, you should check over your trailer to see if it has a 12V power supply or converter. You will want to disable that when operating on battery -> inverter supplied 120V power.

Also, if you wish to have a more elegant solution than plugging the shore cord into the inverter, there are available, inverters with a built-in transfer switch or stand-alone transfer switches, both of which can be hardwired into the trailer's load center and offer automatic switching between inverter and shore power.

Your '65 probably doesn't have many electrical devices to power, if stock. Multiple 120V lights operated together may present a significant load, though. Be sure to read and understand the relationship of inverter draw and battery capacity. Here's one example: Estimating power requirements
jnagy20
Explorer
Jun 27, 2017
Thanks for the info. I settled on running plug out of inverter and into the shore power inlet taking away any chance that well fry the inverter. Not done yet, but understand how this will work. The trailer does not have electric breaks. It's super old school.

I was -2 in 65 :-)
Boband4
Explorer
Jun 27, 2017
I was only 3 in 65 so, I dont have a reference point. Does the trailer have electric brakes? If so, dont you need to ensure a good 12V source to charge batteries for the brakes in case of a breakaway?
kerrlakeRoo
Explorer
Jun 27, 2017
pianotuna wrote:
jnagy20,

Make sure to disconnect the inverter output from the AC panel when plugging into shore power. If you don't you may let the magic blue smoke out of the inverter.

I prefer to plug my shore power cord into my inverter as that makes it ID 10 T proof.

Thats why I had suggested running the current shore cord to the converter when he wanted to run from battery, it would act as a failsafe from being tied to both types of AC at the same time. All of his existing shore power outlets would go live when plugged into the inverter. He would just have to use a stand alone charger for the batteries, powered from an outside source.
Thx
pianotuna
Nomad III
Jun 27, 2017
Hi,

That won't necessarily protect the inverter. The AC side needs to be disconnected on the shore power side.

(That is, if it is a stand alone inverter. Inverter/chargers are a different situation and have an internal transfer switch).

jnagy20 wrote:
Thanks Pianotuna. I was thinking the same thing. My memory is not always so good :-) I did purchase a battery on/off switch which cuts the DC power that will go to the inverter / panel.
jnagy20
Explorer
Jun 27, 2017
Thanks Pianotuna. I was thinking the same thing. My memory is not always so good :-) I did purchase a battery on/off switch which cuts the DC power that will go to the inverter / panel.
pianotuna
Nomad III
Jun 27, 2017
jnagy20,

Make sure to disconnect the inverter output from the AC panel when plugging into shore power. If you don't you may let the magic blue smoke out of the inverter.

I prefer to plug my shore power cord into my inverter as that makes it ID 10 T proof.
jnagy20
Explorer
Jun 27, 2017
Thanks "2oldman". I'm going to give that a try today!
2oldman
Explorer II
Jun 27, 2017
Wiring the inverter directly to the AC panel works fine.