How do you wire an A/C unit to breaker panel for boondocking

[goldentravel]

I have a 2021 holiday rambler navigator and I am curious if anybody can point me in the correct direction for what I need to do to wire up one or possibly two of my roof mounted A/C unit to run off the batteries. I am curious as to what I need to do in the breaker panel to power the A/C unit. The panel has 2 dedicated circuits that go to the inverter from the panel and then back to the panel from the inverter for the pass thru to operate. Then when the inverter is active those circuits are powered. I have about 1700 watts of solar and 800Ah of lithium batteries and a soft start for the A/C that I will be running. I will most likely be getting an upgraded victron inverter but the one thing I am unsure of if what needs to be done in the breaker panel. I would appreciate any help that anybody could give me.

[HarryStone]

You didn't say how big your inverter is, but that would be my first concern. I would think you'd need at least a 3k inverter to run an air conditioner.

[Mark_K5LXP]

Sounds like your inverter is already connected to your panel, which in turn supplies your A/C. Or are you adding a 2nd inverter dedicated to the A/C units?

Mark B.
Albuquerque, NM

[twinboat]

You will need to move the AC breakers to the inverter section of the panel.

See what runs on inverter and find the group of breakers that control them. That would be the section

[goldentravel]

Originally Posted by HarryStone

You didn't say how big your inverter is, but that would be my first concern. I would think you'd need at least a 3k inverter to run an air conditioner.

i will be getting a 3000 watt victron multiplus II

[Smitty77]

If planning on doing longer sustains run of the AC, or two AC's... I'd look into adding a second Inverter to off load that duty from the primary coaches inverter. As Twinboat said, on the CB panel, you'll find the CB's that 'On the Inverter Side'. Adding a second Inverter, will require the feed of the power to the CB, or even a second panel next to it (IF room exists, and the reach of the AC's wiring are long enough to reach a second panel. Which may not be needed, depends upon your current panel config and capabilities.).

Many coaches, our Magna is one, have Dual Inverters installed (Xantrex 3K units on our coach.). And CC also 'beefed' up the alternator to 400A. They set up the front AC unit to be able to run off of this second Inverter, and the 400A provides the power to keep the batteries charged, and feed this front AC unit too. They did this so that in mild cooling demands while driving, the front AC can be on without running the generator. In the Affinity and Magna's with this config, they added 2 more 8D's AGM's to the house bank, for a total of X's 6.

Good to see you're including the Soft Start... IMO, it's a great feature and would be supper to have on all units as OEM!

Smitty

[goldentravel]

Originally Posted by Mark_K5LXP

Sounds like your inverter is already connected to your panel, which in turn supplies your A/C. Or are you adding a 2nd inverter dedicated to the A/C units?

Mark B.
Albuquerque, NM

yes the inverter that I have has two lines going to the panel one of the lines goes to the microwave with a 20A breaker and and a few other plugs with a 20A breaker. and the other lines goes to the fridge with a 15 A breaker and a few other plugs with a 20A breaker also.

its not like I can just add the A/C unit to either of those. that would be way too much.

[Persistent]

Each A/C could be 1300 to 1500 watts. Check name plates on the A/C's. The inverter needs to be big enough to power the sum of the two, plus anything else you want to run at the same time.

800 Ah of Li should be enough to support the inverter through starting and running the two AC for a while. 800 Ah / 25 A = 32 hours theoretical

1700 watts of solar in direct sunlight in mid summer should get 1700 X 6 = 10000 watts per day. That should get 800 Ah for recharging. You will need a substantial controller to push that into the Li batteries fast enough.

The wiring you describe sounds like a combined main circuit breaker panel plus a sub panel for 120 volt loads. You could install a high capacity Victron Multiplus between the main house automatic transfer switch and the main panel. This would power the whole house from the batteries.

The existing inverter could be turned "off" so its ATS stays in pass through mode. Don't trip the circuit breaker from the main to the old inverter to turn it off. That needs to stay "on" for pass through. Turn the old inverter off by other means.

The old inverter/charger could be bypassed and disconnected. Connect input L1, L2, Neutral, and ground to output. Disconnect 12 volt line.

I don't know if your RV has an energy management system. If it does, the EMS must accommodate the changes.

[twinboat]

Once you deplete your large battery bank, you will need to recharge it.

5 hours of solar, in the woods, isn't going to do it, so you will need to run your generator to power the inverter/charger.

If you have a 100 amp charger in the inverter/charger and need to replace 800 AH of used battery capacity, that's 8 hours of charging.

Maybe just running the generator thru the night is a better solution.

[AudiDudi]

Originally Posted by Persistent

<snip>

800 Ah of Li should be enough to support the inverter through starting and running the two AC for a while. 800 Ah / 25 A = 32 hours theoretical
.

Isn't that 800AH at 12vdc and 25 A @ 120VAC? Plus inverter losses.

[Itinerant1]

Just keep in mind when running the air conditioner or any other large load the inverter will be throwing some heat. Depending on where your inverter is and the batteries that area will get warm if it doesn't have proper ventilation. It's one thing to run a microwave for 10-20 minutes off batteries/ inverter, awhole different ball game running a air conditioner or 2 for possible hours. Just something to think about.

[HarryStone]

get a double 20 amp breaker, replace the breaker that is just the microwave, then move the AC line to it. Then you will have the microwave and the AC on the same circuit.

https://www.amazon.com/Square-HOMT20...8941705&sr=8-2

[Itinerant1]

Originally Posted by AudiDudi

Isn't that 800AH at 12vdc and 25 A @ 120VAC? Plus inverter losses.

A 15k air conditioner without the help from solar off of 12v can be in excess of 120+ ah.

[twinboat]

Originally Posted by AudiDudi

Isn't that 800AH at 12vdc and 25 A @ 120VAC? Plus inverter losses.

Right, 25 amps at 120 volts is 250 amps at 12 volts.
So 3.2 hours plus inverter losses.