Help with my new used camper!

[Zflyfisher]

I am having a couple of problems with my newly acquired 1972 trail lite camper. First question is that my inside lights do not work. I only have 120 volt system and checked the breaker, nothing worked! It only powers a couple of lights but it would be nice to have this work in the ear future. I would also like my camper to run off of 12 volts, but there is no battery box or place for a battery. Thanks for the help.

[Zflyfisher]

I checked the bulbs and still no lights. Can I attach a 12 volt battery to regular 120 wiring? I have a great place under the seat to put a battery but have no clue how to wire to current 120 system.

[Donna D.]

Hi Kevin, welcome to FiberglassRV. I'm going to leave the electrical question to the experts. But, wanted to take the time to welcome you to a place where kind, friendly folks hang out to discuss molded trailers.

Post pictures when you can, we love to look at pics

[Roy in TO]

Originally Posted by Zflyfisher

Can I attach a 12 volt battery to regular 120 wiring?

12V DC and 12V AC are two totally different systems, the only way you should safely connect the two is to put something between them.

An inverter is required to go from 12V DC to 120 V AC.
A converter is required to go the other way, or you could use a battery charger to charge your battery.

Here is a good book that will tell you enough to know what to look for and ask the right questions:
Solutions to 12 Volt Electrical Problems, RV Electrical Systems, 'Managing 12 Volts by Harold Barre' ... Summer Breeze Publishing

[mcbrew]

Be careful where you install a battery... Standard car/RV batteries put off explosive hydrogen gas when charging. I only do weekend camping in my Scamp, so I use a "jump pack" as my battery. I charge it up at home and take it with me. Mainly, it is just running the interior lights, which a re 12v LED bulbs. Also, I wired in a cigarette lighter outlet for charging iPhones, iPads, etc. the jump pack I have can also jump start a car battery, has a built in tire inflator, can provide up to 400 watts of AC power, and has a built in LED light. Check out Harbor Freight for item number 96157.

In these campers, there is usually a 120v AC fluorescent light on the wall and a couple of 12v DC lights on the sides of the cabinets. Of course, options differed, and with a well used camper, there can be many changes made along the way.

[David Tilston]

To add a 12VDC system is no small task. You will have to run a totally different set of wires for the new 12VDC lights. Also, you will have to consider some way to charge the 12V battery. The easiest way to do this is from the tow vehicle. If you have a 7 pin, (six on the outside and one in the middle) trailer connector, one of them is 12V power.
You may also consider a power converter to convert 120VAC to 12VDC. There are versions that will also act as a battery charger.
The fact that some of your 120VAC lights work and some don't tells me that you probably have a wiring issue. Copper corrodes. Where it corrodes it causes a high resistance point on the circuit. When current flows through these high resistance points, heat is generated, and wires may break. At 120VAC this can be quite a hazard.
Were I you, I would probably convert all the 120VAC lights to 12VDC LED lights. I would pull out the 120VAC wiring. Before I pull it, I would tie some #14 seven strand wire to it and use the 120V wire as a fish tape to pull the new wires into the same place. Then using a converter/battery charger, I would power all the lights off the converter/battery.
You will probably have some 120VAC plugs in the trailer as well. These can be useful. I would examine the wires, especially the ends where they terminate in the outlets. If they are green with corrosion, I would replace them. Standard #14 solid house wiring will do. These will connect to where the 120VAC comes into your trailer, preferably on the other side of a breaker.
That brings us to the subject of over current protection. Every wire should be protected by either a fuse, or a breaker which is rated for the size of wire you are using, 15 amps for #14. The DC Circuits will need an over current device as well.

If you are getting the impression that this is not simple, you are correct. given that you asked if a 12V battery can be used with the 120V system, I am assuming that this is new to you. You should probably consult an electrician, or a qualified RV service shop for advice.

[Zflyfisher]

Thanks everyone for your help. So I used an volt meter today and it looks like my breaker is good but I am not getting any juice to the lights. I guess I am going to try to use a ohm meter to see if my wires have been broken or something. Most likely I will just move the system to a straight 12 volt system. Does anyone know if there is a 12 volt electrical output for my wife to plug in hair drier or charge iPods on the road? Thanks

[RogerDat]

See the prior comment about an inverter. It changes 12 volt DC (from battery) into 120 volt AC. The smaller ones will have built in outlets, some of the bigger RV ones will have a place to connect the 120 volt wiring to you plugs or circut breaker as an electric source.

They do (or did) make 12 volt hair dryers but not sure how well they work. If there is a car charger for the device you can charge from 12 volt using a cigarette lighter style 12 volt plug from RV store OR plug in a portable 12 volt to 110 inverter and plug into that.

No matter what you need to add up the watts you will use, hair dryer is a lot, as is a coffee pot or any other heating appliance. Laptop, cell phone, iPod or camera not so much.

You need to have an inverter that is rated to deliver enough watts to run the appliance PLUS enough battery to supply the watts for the amount of time (watt hours) you will run the devices. Almost every device will have a label or plate that says how many watts it draws.

E.G a blow dryer that draws 60 watts run for 1 minute uses as much battery as a 1 watt light run for an hour. (not exact but as a general thing) and drawing an RV battery below 50% is hard on them and tends to cause them to die quicker.

Example of inverter to look at not a recomendation: Amazon.com: Cobra CPI 880 800 Watt 12 Volt DC to 120 Volt AC Power Inverter with 5 Volt USB output: Automotive

You may find that as you track your power with your meter from circut breaker to switch to appliance/plug you will find your issue, also I'm betting you know at least one person that has added lights or plugs to a basement or a garage who could help you fix the 110 system. Not really any different in an RV than in a house.