Need help rewiring Travel Trailer

We just got our first camper in the form of a 1973 travel trailer.  I have a book on maintenance coming next week but we are leaving on a 10 day trip next friday so I need to do some work this weekend.  The trailer is in great shape and everything is working in the interior, but I think the electrical system is kind of sketchy from what i can tell.  First sign, was when we were looking at it to purchase there was a set of dual outlets on the aft part of the cabinets for the kitchen, near the back bed/couch.  It had a label on it D/C.  I looked at it and said that can't be DC it must be mismarked.  While opening things up to check out systems, I found a very significant wire from the battery box to the outlet, so yes someone wired 12V to 110 outlets.

Other issues in the trailer are

No Converter
Only 2 12V lights one in bathroom and one in main room, would like more
Lots of old 110V lights (1970 era), might want to replace some of them.
There is an old cord that I pull out from an external socket without a cover to plug into shore power
it goes into a Breaker panel with 2 C.B.s  Since I have an Air Conditioner so I figure one CB is for the Air and the other is for the rest.

The plan
I picked up a used combination battery charger/converter.

So the short term plan is to:
Change the exterior outlet receptacle for the shore power for something cleaner.
Add another CB in the panel for the convertor.
Wire the 110V to the convertor.
Attach the battery to the battery charger side of the converter.
Move all the 12V wires to attach to the convertor directly instead of running directly from the battery.

I am good basic electrician, but not familiar with RVs.  Any suggestions on how to do this?  What kind of wiring should I use?

Depends on how long ur going to keep the traylah and what ur budget is.

For shore power I like the Marinco inlets.  Very clean looking setup and easy to replace the shore power cable when necessary.

There are several good online sources for components that are better and cheaper than a local auto parts store.  http://delcity.com for example though I have not bought from them.

The marine places generally have better quality electrical stuff but it is priced accordingly.

Randy at bestconverter.com for the converter.

Spend the money and get a $100 crimp tool for the terminals.  It makes a huge difference in reliability over the long run.

Thanks Jammer,
I already have the converter $50 used.  I do not see owning this trailer for too long more than 2 years, if we like it enough we will upgrade in the future.  Does not mean I do not want to do it right, just cheap.  I know all about marine products because i have owned sailboats.  I will invest in a good crimper as I like tools and intend to do a lot of wiring over the years.  If the load on the trailer is light, is there a need to go expensive Marinco, it has marin(e) in the word =3x price. 

Help me with this if I am wrong but, I see the 110V lights as a waste of space, except A.C. .  If we have shore power we have a converter and 12V DC power.  Is there a reason to keep any 110V lights except for outside for the greater output?  As it is we only have 2 lights in the trailer with battery power.  The trailer power requirements are minimal. 

Propane runs
Fridge
Stove
Oven
Hot water

DC runs
water pressure (pressure pump)
3 lights (forgot about outside light (one ac and one dc)

AC runs
Air conditioner
Converter
Fridge (optional)
lights

Besides these built-in needs I see the following
laptop
Cell phone charging
MP3 player and speakers.

So would a 20A shore power setup work for this rig?
I have not seen a main CB, yet have not looked too far.  If we add a microwave, would this be an issue with the AC and micro running simultaneously?  Should there be a "Main" CB?
Can I run Home Depot style Romex in the interior of the trailer or should I use SJO or the like?

Most RVs have only 12VDC lighting.  The only 120VAC light in our motorhome is a table lamp that we added.

If you want to run an A/C, then you need to wire it for 30A.  Add a microwave and you will probably have to run only that or the A/C at any one time.

If you are going to install an a/c, I'd go for 30A shore power. Unless you pop for one of the high efficiency models, an a/c is going to consume 13-14 amps all by itself. And microwave is a high amp device - the input power is 50% or more greater than the rated output power, so check the rating plate for the actual power requirement. For example, a 1200 watt micro typically needs 15 (1800 watts) amps to run. So yes, a/c and micro at the same time is an issue on 30 amps.

Romex is fine.

You need a main CD if the aggregate of all the individual CBs exceeds the capacity of the power source. If you had 3 x 15 amp circuits on a 30A shore connection, you need a 30A main breaker. If you had only 2 x 15A, then no main is required if the source is 30A, but would be needed if the source were only 20A Got it?.

Modern RVs use 12v lighting almost exclusively. 

Thanks Guys,
Thats what I thought for lighting, no need for 110V lights.  The trailer already has A/C, which was the only one in our price range with one.  With 1973 technology I doubt it is an efficient one. 

We have no microwave but it is the only thing  could think of adding.  So i will put in a 30A shore power to cover that option.

Does CD mean Circuit disconnect? 

Replacing all the 110V lights may be a chore.  Hopefully the lights are on a separate run from the A.C. outlets so i can just change the wiring to the 12V side and then change the lights.  The roof paneling and some of the side paneling seems to have been redone.  I do not see an easy way to get at the wires or run new ones. 

Any suggestions on fishing wires or do I have to remove the panels to get to them? 

How do i reattach the panels?

For the 12V wiring should I use 12 ga romex as well?

So this is what I came up with.  It turns out there is no main circuit breaker, however there is a few extra spots in the Breaker box.  I purchased a 30A CB and will be wiring the 10g 30 amp service directly into the 30A CB instead of the Lug for that leg of the panel.  This will then act as the main CB for the whole panel.  I have a 20A CB will use to wire the converter into the breaker box.  I can't find room to mount the converter flat so I will be mounting standing vertically.  Can anyone see a problem with that?

The converter should mount any way, as long as it s fan isn't blocked.

Photobug said:

I have a 20A CB will use to wire the converter into the breaker box.

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It will work but they usually draw something like 7 amps max so a 15 amp circuit is customary.

  I can't find room to mount the converter flat so I will be mounting standing vertically.  Can anyone see a problem with that?

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They vary with some of them relying on a particular orientation for cooling especially if they have no fan.  Read the destructions.

Photobug said:

Thanks Jammer,
I already have the converter $50 used.  I do not see owning this trailer for too long more than 2 years, if we like it enough we will upgrade in the future.

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I've never found the perfect RV boneyard out there but they are rumored to exist and if u have more time than $$ you could probably pull some of the parts you will need.

If the load on the trailer is light, is there a need to go expensive Marinco, it has marin(e) in the word =3x price. 

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It's not about load, the marinco inlets make for a detachable shore power cord which you can then stow somewhere convenient.  The alternative is a permanently installed shore power cord which then has to be stowed in a dedicated compartment.

Help me with this if I am wrong but, I see the 110V lights as a waste of space, except A.C. .  If we have shore power we have a converter and 12V DC power.  Is there a reason to keep any 110V lights except for outside for the greater output?  As it is we only have 2 lights in the trailer with battery power.  The trailer power requirements are minimal. 

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The 120v lights are a throwback to olden times before there were decent converters.  Airstream got rid of them in the early 1960s.  They have no benefit at all.  You can get 12v lights that are just as bright.

Can I run Home Depot style Romex in the interior of the trailer or should I use SJO or the like?

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Be careful about sharp edges, if you cross metal frame or skin you have to use a plastic bushing so the metal doesn't cut into the wire.

Photobug said:

The trailer already has A/C, which was the only one in our price range with one.  With 1973 technology I doubt it is an efficient one. 

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The new ones aren't any better.  The improvements in A/C efficiency in the last 40 years are all about increasing the size weight and purchase $$$ of the A/C to buy efficiency, so you see thermal expansion valves, larger condensers, larger fans, condensate slingers, and somewhat larger evaporators, none of which have made it to RVs.

Replacing all the 110V lights may be a chore.  Hopefully the lights are on a separate run from the A.C. outlets so i can just change the wiring to the 12V side and then change the lights.  The roof paneling and some of the side paneling seems to have been redone.  I do not see an easy way to get at the wires or run new ones. 

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If it were me I'd switch the existing wiring to 12 volt and remove any 120 volt outlets that may happen to be on the same circuit.  Run new power to the air conditioner if necessary.  You can re-use the existing light fixtures, just use 12v bulbs.  There are compact fluorescent 12v RV bulbs now that fit in a regular Edison screw base, search google or amazon.

Any suggestions on fishing wires or do I have to remove the panels to get to them? 

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Have someone you don't like who owes you a favor come help.

For the 12V wiring should I use 12 ga romex as well?

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You can although usually people use automotive type wire because it's stranded and easier to fish.

Okay I have the panel all wired up and like how it is working.  I went back to HD and talked to another electrician and he liked my idea of wiring the CB panel through a CB to protect the entire circuit then jumper the two legs together.  The first guy was actually upset at what I intended to do, buy could not tell me why it was bad, I felt better having another electrician validate my idea.

So I have it all wired and looking good.  The one problem is the converter I have has two wires a red and a blue, and then a lug.  All the 12V neutrals go to the lug.  The red wire goes to the Battery to charge and the blue wire goes to the house 12V lines.  So far i have only hooked up the AC side and the battery portion of the converter.  When I have it wired and the battery attached I hear a clicking every minute or so from the converter and the wire from the battery heats up.  I am thinking this is not normal.  I have yet to turn on the 110V circuit to it as i am afraid it is not working correctly and do not want to damage the battery or any of the associated wiring.  How can I test this? 

My other option is there is another converter for sale in town for $100 a new WF-9800 Series rated at 75 amps.  I think this may be overkill but the price is right.  Would the 75A model cause problems running it on a 30 A service panel?

Definitely something wrong with the converter. The click is probably an auto-reset circuit breaker tripping to protect it. And a hot wire is a bad sign too.  Reversed polarity, maybe??

A 75A converter is overkill, but even if it actually has to produce 75A (unlikely), that's only 900 watts input. Pulls maybe 8 amps from the load center. Most times it will be less than half that. WFCO makes a nice converter, but they have a tendency to die after about 4 years. Not all of them, but more than a few. Maybe the 9800 model will be better.

When you say they last 4 years, is that full timing it or if I put this in and only use it a month or so in the summer...  Used part time, do they still have a tendency to go bad?  I guess I will be in a better RV in 4 years if it goes as planned anyways but do not want to put in anything unreliable.

Sometimes a new battery that's near complete discharge will draw more than the converter can supply.  High buck converters have current limiters that scale back the output accordingly.  Some low buck converters misbehave.

Be sure you don't have a short in your battery wiring.

Use an ammeter to check the converter output and see what it's doing, and a voltmeter to see how hard it's pushing the batteries.  There are magnetic DC ammeters that can be placed over a wire so you can see the current flow without having to rewire everything.

If the voltage is in spec (14 point something or other) and the current is high it may just be that your batteries are really discharged, and you might have to connect them to the converter one at a time just this once to get them to charge.  If the voltage is, say, 11 volts and the current is high well you have a shorted cell and need a new battery.  If the voltage is, say, 2 volts, and the current is high, then you have shorted wiring somewhere.

Thanks Jammer,
There is only one battery and it is brand new and fully charged at this point.  I will run tests on the converter though just to see what is going on.  I do like the thought of a newer one though as it will smart charge the battery verses whatever the older styles did.  Also the place where I got the older charger has some awning poles I could exchange the converter for.

I am out of state today so no testing.  Hopefully all works out tomorrow and I will be home so i can do some more work, testing etc.  My one other option is to wire the battery to some lugs and use my car battery charger to charge the battery when plugged in.  I don't think we will be anywhere for more than 2 days so the battery will be charged by the TV each day.

So I was supposed to meet up with the seller of the newer converter when I had a chance today.  I first had one more thing to try out.  I pulled out my multitester and did some sleuthing.  Without the battery plugged in, I was getting 13+volts on the converter on the house power side, and 8+ volts on the battery side with out any arching, sparking or clicking.  I then tested the wires coming into this box from the battery.  Turns out the polarity was backwards.  I kind of figured as this wire I was using was the same one coming from the battery to feed the AC 110 V socket, but marked DC on it.  The previous owner was even worse at electrical work than I thought.

I think it is now working but is hard to test as there are few 12V outlets in the trailer.  I tried testing the cigarette lighter and think I was getting a rise from 12.44 to 12.66 when the converter was off vs on.  It is hard to tell as it is hard to reach in and get an accurate reading with my probes.  When the wife gets home I will test the circuit while she turns on and off the CB to the converter.

I believe it is all working.  My question is how do I wire this setup now?

I have 25' of four strand 16 gauge wire I was thinking of splitting into two strands to run DC runs into some other areas in the trailer.  Currently all the 12V comes off the battery, but this newly installed converter has a separate output for the house power other than the battery. 

• Will this house power supply work off the battery's power when the converter is not powered by AC or should I keep things powered by the battery where it will get power whether the converter is working or not? 
  
  Should I run a bank of 10A fuses near the source for each 16 guage run?

Photobug said:

Will this house power supply work off the battery's power when the converter is not powered by AC or should I keep things powered by the battery where it will get power whether the converter is working or not? 

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Usually even though there are two output lugs they are equivalent except possibly being served by different fuses or breakers. 

Should I run a bank of 10A fuses near the source for each 16 guage run?[/list]

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They should be fused or breakered at 10-15 amps.  Depending on the load it may make sense to have some fuses serve more than one circuit to cut down on the number of fuses or breakers required.

I usually use breakers.  The cost is about the same and fuses are a real nuisance for troubleshooting.  There are various styles of breakers, the auto reset ones are most convenient but arguably don't provide as much safety, the manual reset ones are safer but more of a nuisance.

The one problem is the converter I have has two wires a red and a blue, and then a lug.

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What kind of converter is it?  Some older ones, Magnetek in particular, had an unregulated, unfiltered output as a main output, then a smaller capacity filtered output to charge the battery.  The filter output also was used to feed electronics like a radio or TV outlet that would hum if fed from the main unfiltered supply.

If you connect the battery to the main, unfiltered output it acts like a capacitor and will raise the voltage to unacceptable levels.

Lou Schneider said:

What kind of converter is it?  Some older ones, Magnetek in particular, had an unregulated, unfiltered output as a main output, then a smaller capacity filtered output to charge the battery.  The filter output also was used to feed electronics like a radio or TV outlet that would hum if fed from the main unfiltered supply.

If you connect the battery to the main, unfiltered output it acts like a capacitor and will raise the voltage to unacceptable levels.

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Is there a way to test/know what kind of power I am getting from this converter?  I will post the model information when I get to work on it tomorrow?

Thanks for all the info everyone.

I had the converter hooked up and it all worked well for the entire trip.  I took many tools with me on the trip and was planning on finishing the wiring enroute but was too busy enjoying OR and CA.  I did however test the wiring and the outlets and lights are on completely different circuits.  So the plan is to change the wiring to this circuit to run off a 12v circuit and use 12v bulbs in those fixtures.

I will begin to look closely at the converter now to see what kind of power it is producing on the two legs.  I will also run a line of 12V outlets from it to places around the trailer using one main line using 10G wire to a fuse block with 16G running to other outlets.  With one 12G wire running to an outlet for use with the inverter.  The inverter attached to my whole big multifunction rig did not work, so I had to buy one along the way, may upgrade it to a larger one though.  I don't plan to need much in the way of 120 V though just to charge MP3 player and camera batteries.

All in all everything worked well but look forward to improving the wiring to higher standards.  Thanks for all your help.