Adding a second AC unit

[Jusjay]

Can I add a second AC unit and run it and the stock AC off the the 4K generator by adding soft starts to both AC?

[Ron1Z]

Yes you can add a second A/C unit, but the 4K generator will not be able to handle the two A/C units unless you run one at a time. I added a second unit to my Windsport and ran a seperate 20Amp circut.

[Bob Denman]

I'm the least qualified person in here to give electrical advice...
But there's probably a good reason why most Tv's with 2 a/c units have a 50 amp power supply, and at least a 5500 watt generator...
You can probably make it happen; if it's worth it for you.
Good luck!

[Jusjay]

Sitting in a KOA in Grand Junction Co. after driving from Utah. Yesterday it was 107! Today’s high 102. Yea right now I would break into the grandkids college fund if (IF) it would cool down this heat box.

[Bob Denman]

It seems like a good time to grab the cooler full of "Barley-pops", and keep it well-stocked and handy!

[16ACE27]

You have a 13.5K BTU AC unit. You can easily add a high efficiency 8K BTU or 13.5K BTU unit in your bedroom by replacing the existing vent. Yes, the 4K generator can handle both but not much of anything else, Fridge on gas, Water Heater on gas, no microwave, etc. Your existing A/C uses under 15 amps, an 8K BTU under 10 amps.

[Jusjay]

If I used a 13.5K as a second AC and added soft starts to both units would that make it easier on the generator during start ups and cycling?

[Chance]

Correct, NOT ALL AIR CONDITIONERS ARE THE SAME. People keep ignoring this. Some require around 10 Amps and others over 15 Amps at rated conditions. Multiply by two and compare to 30 Amps and it’s easy to see different results.

Thor and other manufacturers are building motorhomes with two 11,000 BTU/hr Power Saver air conditioners that run on 30-Amp service or 4,000-Watt Onan. However, when you want to run another large load like the microwave, one of the A/Cs has to be turned off first. On new 30-Amp motorhomes with two Power Savers this is done automatically by power management system, but you could do it manually.

I’d first look at existing air conditioner specifications to see how much power it requires, then decide how to proceed from there.

[Beau388]

Originally Posted by Chance

Correct, NOT ALL AIR CONDITIONERS ARE THE SAME. People keep ignoring this. Some require around 10 Amps and others over 15 Amps at rated conditions. Multiply by two and compare to 30 Amps and it’s easy to see different results.

Thor and other manufacturers are building motorhomes with two 11,000 BTU/hr Power Saver air conditioners that run on 30-Amp service or 4,000-Watt Onan. However, when you want to run another large load like the microwave, one of the A/Cs has to be turned off first. On new 30-Amp motorhomes with two Power Savers this is done automatically by power management system, but you could do it manually.

I’d first look at existing air conditioner specifications to see how much power it requires, then decide how to proceed from there.

Very true. I have a Coleman Mach 3 PS (13,500 BTU) up front and a Coleman Mach 8 in the rear (13,500 BTU). The Mach 3 PS draws 12 amps @120 volts on a 100 degree day in the full sun and the Mach 8 draws 14 amps @ 120 volts. I have a Progressive EMS (50 amp) so I can monitor each of the coach's legs. I still have enough overhead on the Onan 4000 to run the RV frig on electric. Cycling is not a problem. If you don't have a Magne Shade or Reflectix on the windshield, the front 5 feet always stays hot. Ceramic windshield coating also helps but not as much as the Magne Shade. By the way it is going to be 105 here today and 108 tomorrow

[Rey&Reina]

Originally Posted by Ron1Z

Yes you can add a second A/C unit, but the 4K generator will not be able to handle the two A/C units unless you run one at a time. I added a second unit to my Windsport and ran a seperate 20Amp circut.

What did you do for a circuit breaker on the 20amp line? I would like some protection for this line. Wish I could find a surge protector.

[raymillsus]

Have you looked at one of these I just got one and seems to be pretty amazing and increasing air flow. and the return goes from 4x16 to 16x16.

https://rvairflow.com/

[raymillsus]

I have a Inferno 3912 and I have added a second AC to the bedroom up front. My question is 2 fold.

1. Does anyone know if the Garage vent is prewired for an AC unit?
2. If it is not prewired how difficult is it to put in a power cable back to the middle of the camper?

Thank you

[IDguy]

BTW I’m sure you can run both units with 4,500 watts. But if they both want to start their compressors at the same time they might flip the breaker. That doesn’t happen too frequently if you follow above advice: no other large electrical loads like fridge, water heater, and microwave.

I have run my two units with 30 amp shore power. Usually get a few hours between breaker trips. Usually trips the post breaker.

[Jimbo56]

Originally Posted by raymillsus

Have you looked at one of these I just got one and seems to be pretty amazing and increasing air flow. and the return goes from 4x16 to 16x16.

https://rvairflow.com/

Did you notice a major air flow increase? And did it keep yours cooler longer. At 95 outside in the sun, at 4 pm, mine is blowing 60 degrees out the vent. 81 in the coach. I’m told 20 degree difference is all I can expect. I’ve got reflective stuff cut to fit all windows. Pillows in vents. Skylight in bathroom blocked off.

[Cherry3z]

Originally Posted by raymillsus

Have you looked at one of these I just got one and seems to be pretty amazing and increasing air flow. and the return goes from 4x16 to 16x16.

https://rvairflow.com/

I just looked this over. The concept certainly seems solid. The divider between the supply and return was always pretty poor to start with, even if you mucked with it some.

The only thing I'm unsure about....with this design, you appear to lose what I call the "flood cooling", where you open the vents on the unit itself, to cool just the room it's in. I have a single unit RV, and sometimes when I just want max cooling in the living room, I open those which effectively stops the ducting to other rooms. But, seems like using this to make the ducting more efficient, and just closing off the vents in the other areas/rooms would be worth the trade, if it works as well as they say.