Pre-planning questions for a new AC

[Dremel]

Just finished running all my electric in my gutted airstream.
Trying to think of anything I may need in the future before putting in the skins.

I will be using my current air condition for now, but want to preinstall wires and drain tube for any future upgrade to either a Penguin, or Mach 8

What size is the drain tube ? 3/8"id ?
Where does it connect on the AC? in front or back, middle ?

Thermostat, how many wires and size of wire ?

Where is best place to put the thermostat in the airstream ?

Thank you

[mikextr]

Here's info for the Thermostat

Here's info for the drain tube. Hint: it's 1/2" I.D.

[Dremel]

Thank you, I had been looking for manuals.

so 1/2" drain line to about the middle of the unit

and a power wire (18-22awg) from the breaker to the ac ( I ran a 12 awg )
and a 3 wire (18-22awg) from the ac to the thermostat


Now to decide on best location for thermostat.

[mikextr]

Just for clarification- that is a 12VDC dedicated power supply from the converter or the battery.

Don't know if there is a best thermostat location. I just rewired in the original locations. Don't forget the thermostat and 12VDC power wiring for your heater.

[lahrfarm]

The penguin II low profile and thermostat I am looking at listed the following wires.
1) 12/2 120v
2). 12g 12v, + and -
3). 18/20g 2 wire from heater
4). 4 wire phone cable from A/C to Thermostat

[Dremel]

Thank you both for the additional info.

[BillfromWI]

If you haven't already thought out how you would cable a solar installation I suggest you think it over. I suggest you would want 4-2 or 6-2 AWG cable from the roof to wherever you would place a controller--the closer to the batteries the better. I used two 4s.

You could install an AM Solar Combiner Box https://amsolar.com/rv-solar-panel-kit/combiner-boxes on the roof with the required hole through the skin and provide means to facilitate the cable pull later.

The combiner box comes with four (4) solar panel cable knockouts molded in. It is definitely waterproof when properly calked to the roof. If you decide to install panels the cable glands that come with the box are water proof if used with 10-2 round cable that AM Solar sells for panel connections.

I had the joy and angst of "blind" locating and drilling offset holes in the outer and inner skins for my cable--something to avoid if possible.

[Steve Bryant]

Originally Posted by Dremel

Thank you, I had been looking for manuals.

so 1/2" drain line to about the middle of the unit

and a power wire (18-22awg) from the breaker to the ac ( I ran a 12 awg )
and a 3 wire (18-22awg) from the ac to the thermostat


Now to decide on best location for thermostat.

Dremel,
You did the right thing to use 12 AWG for the power wire as that is what Dometic and probably other manufacturers recommend. Roof mounted air conditioners or heat pumps up to 15,000 BTUs are just under fifteen amps @ 120 VAC and could technically run on 14 AWG wire as a minimum, but the next larger size 12 AWG is preferred. Also, the wire needs to be 12-2 with Ground, not simply 12-2. When you "rough-in" your wiring, make it 12 to 18 inches longer than you actually think will be required at each end for every outlet, etc. because you may need more wire than you initially think that you will need.

Regarding a thermostat, you may not want a remotely mounted thermostat. It doesn't hurt to run the wiring, but a simple interior mounted air distribution box (ADB) with an integral thermostat and fan speed switch may be sufficient for your needs. Also, some thermostat systems are three wire affairs whereas others do require a four wire serial data cable (often a phone wire with the jacks crimped in a certain arrangement). Also, here's a link to a Dometic Brisk Air/Penguin installation manual.

[Dremel]

I ran 12 guage for the ac (alternating current) and 12 guage for the dc control board. Now i will run the wires for the thermostat. Thanks .

For solar, i guess im confused. I ran two 8 guage from battery area to roof area. Based on the gopower manual for their 500 watt kit, they only provide 10 guage between the rpof and comtroller MPPT. Then big cable between the controller and battery.
Other companies are sayimg 6 amps per 100 watt, but then suggest much bigger vable than 6x5=30
6amp 5 100 watt panrls. 30 amp, 10awg shoud have been ok,

[BillfromWI]

8 AWG will work. If it is connected to a 36 cell panel producing 20 amps 16 feet of it will result in 3% voltage drop. I have read that professional installers regard a 5% drop acceptable for a low voltage installation.

Voltage loss is function of voltage, power, length, and wire gauge. Higher voltage has less loss per foot, higher power (amps) has more loss per foot. More panel wattage will need larger wire to maintain acceptable voltage drop.

The operative term is "acceptable". I wanted very low voltage drop. I have 3 100 watt panels. My cable run from the combiner box to the controller is about 15 feet. I will be the first to admit that 4 AWG may be overkill for this installation but I was replacing the original 2 50 watt panel factory solar option that used 10 AWG for all connections. It was almost useless, even with a new Renogy MPPT controller. I was not going to save a few dollars on cable because my plan was to never do this again.