Air Conditioner: 12V Battery Powered A/C for Off-The-Grid Vanlife

Air-Conditioner-12V-Battery-Powered-Off-The-Grid-Vanlife-(heading-1920px)

Air Conditioner: 12V Battery Powered A/C for Off-The-Grid Vanlife

12V "battery powered" air conditioners for off-the-grid usage are starting to hit the market. Manufacturers like Nomadic Cooling Co. claim those 12V A/C units can be 70% more efficient than traditional 120V A/C rooftop units and are therefore suited for vanlife. In the following guide, we will compare 120V VS 12V air conditioning and define an electrical system that can support it and provide an acceptable autonomy. Keep cool and carry on!

Logo-FarOutRide-Winter-Vanlife-(nov-2019)

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1- 120V VS 12V Air Conditioner

1.1- What's The Difference?

A 12V air conditioner uses a highly-efficient compressor designed to work directly with 12V DC current. A 120V air conditioner uses a compressor designed to work with 120V AC, and not only this compressor is more energy hungry, but there is also an energy loss of about 15% during the conversion from 12V DC to 120V AC.

This might reminds you of 12V vs 120V refrigerator (faroutride.com/fridge-guide)! In both cases, it’s the 12V compressor that makes it so efficient.

1.2- Efficiency

Nomadic Cooling Co. claims their 12V “battery powered” air conditioners are 70% more efficient than traditional 120V air conditioners. Unfortunately we’re not in a position to verify this claim, as it would require testing both 12V and 120V units on our van in real-world situations. So let’s take a look at the maximum current specification for both units:

Nomadic Cooling Co.
9,550 BTU (75A compressor option)

73 amps

max current at battery bank (12V)
Dometic Penguin II
11,000 BTU ("High-Efficiency" model)

~175 amps

max current at battery bank (12V)

That gap doesn’t prove that the Nomadic Cooling Co. is more efficient, as the Dometic being more powerful might run less often (shorter duty cycle). However, it’s a good indication that the 12V unit is more suited for off-the-grid usage…

1.2.3- Cost

Nomadic Cooling Co.
9,550 BTU (75A compressor option)

$3,895

USD Approx.
Dometic Penguin II
11,000 BTU ("High-Efficiency" model)

$875

USD Approx.

Well, that’s a massive price gap. So what can possibly justify to purchase a 12V unit when it’s more than 4x the price? See our decision tree below…

1.2.4- Decision (120V vs 12V)

Off-The-Grid

Arrow-down-left
12V Air Conditioner
(Battery Powered)

Shore Power

Arrow-down
120V Air Conditioner
(Serviced Campgrounds/Generator)

If you really want off-the-grid air conditioning, 120V is just not an option. Don’t get us wrong: you can actually make a 120V A/C run from the battery bank, but you’ll have a few minutes/hours of autonomy at best (even with going with, let’s say, 600Ah of Lithium batteries. That’s over $6,000 in batteries alone). Not convinced? Here is a question we got recently (and we get similar questions occasionally):

Hello. I have a Victron 3000w multiplus inverter/charger and a Dometic brisk 2 on the roof […] and after I connected the Victron it drained the batteries quickly with only brief use of the ac fan and a couple of minutes of actual ac. Do you have any feedback?

Our feedback is: there’s probably no issue at all with your setup, except that unfortunately you had the wrong expectations about air conditioning… The solution here is to use your AC on shore power only, or to upgrade your electrical system (battery bank most notably) and your AC for a 12V unit. We’ll show how below.

2- Buying a 12V Air Conditioner

We’d personally go for the Nomadic Cooling Co. 3000 model with 75A compressor, because it’s easy to install (it fits a 14 x 14 fan cutout) and it’s easy to wire. (The 100A compressor option or the 4000 model is more powerful, but power consumption is too high for off-the-grid usage):

Nomadic Cooling Co. 12V Air Conditioner
3000 | 75A Compressor

3- Electrical System

3.1- Wiring Diagram & Items List

Download our “High-Power” wiring diagram (faroutride.com/wiring-diagram), wire the 12V air conditioner per image below (“12V AIR CON”) and make sure to use a 400A fuse with 4/0 AWG cable (“MAIN”) as annotated below:

12V-Air-Conditioner-Van-(Sprinter,-Transit,-ProMaster)-Wiring-Diagram
High-power wiring diagram (modified for 12V A/C). Download it here: faroutride.com/wiring-diagram

A few clarifications:

  • Use the dropdown menus and input all the wire length, in order to get all the correct wire gauge  (e.g. youtu.be/9MEGls0qLZY)
  • Because the air conditioner increases power demand on the electrical system, we’d recommend selecting a 2000W inverter/charger. It’s possible to go with a 3000W inverter/charger, but be aware that this might overload the system during peak power (e.g. when the inverter and the air conditioner are both running simultaneously at max power).
  • The 12V air conditioner is connected to the bus bars via a 100A breaker. The correct wire gauge varies with the length and can be determined with this calculator: WIRE GAUGE CALCULATOR. Or simply put, 1 AWG gauge will work for any length under 30 feet total (15 feet red + 15 feet black).

Items List

12V Air Conditioner
112V Air ConditionerNomadic Cooling Co (3000 | 75A compressor)1View
21 AWG Cable 15 feet Red + 15 feet BlackTo connect A/C to breaker and bus bar1View
3Lugs, 1 AWG Cable, 1/4″ RingTo connect to breaker (2-pack)1View
4Lugs, 1 AWG Cable, 3/8″ RingTo connect to bus bar (2-pack)1View
MAIN
#ItemDescriptionQuantityView on Amazon
1Class T Fuse, 400ABlue Sea (Catastrophic Fail Safe)1View
2Class T Fuse BlockBlue Sea (Holds the Class T Fuse)1View
3System SwitchBlue Sea (Main System Switch)1View
4Bus Bar (600A, 4 studs)Blue Sea2View
5Cover for Bus Bar (for 600A 4 studs)Protect the Bus Bar2View
640A Breaker/Switch, Surface MountBetween Fuse Block and Bus Bar1View
7Fuse Block (12 circuits)Blue Sea (12V Distribution Panel)1View
8Fuses KitAssorted Fuses (2A 3A 5A 7.5A 10A 15A 20A 25A 30A 35A)1View
9Battery MonitorVictron BMV-712 with BlueTooth1View
10Cable, 4/0 AWG, 5 ft RedBetween battery and Bus Bar1View
11Cable, 4/0 AWG, 15 ft BlackBetween battery and Bus Bar + Ground1View
13Lugs, 4/0 AWG Cable, 5/16″ RingConnect to Bus Bar, Terminal Fuse Block and Battery (Pack of 2)1View
12Lugs, 4/0 AWG Cable, 3/8″ RingConnect to System Switch and Shunt (Pack of 10)1View
14Cable, 8 AWG, 5 ft Black + 5 ft RedBetween Bus Bar and Fuse Block1View
15Heat Shrink Terminal Ring, 8 AWG Cable, #10 RingConnect to Fuse Block (Pack of 3)1View
16Heat Shrink Terminal Ring, 8 AWG Cable, 1/4″ RingConnect to Breaker (Pack of 3)1View
17Heat Shrink Terminal Ring, 8 AWG Cable, 3/8″ RingConnect to Bus Bar (Pack of 3)1View
Battery
1LiFePO4 400 AhBattle Born LiFePO4 100 Ah 12V6View
24/0 AWG Cable in 5/16″ lugs, 1 feet Red + 1 feet BlackSpartan Power5View
Solar
1350W SolarNewPowa 175W Mono Panel2View
2Extension Cables, 8 AWG, 15 ft Red + 15 ft BlackWith MC4 Connectors1View
3Double Cable Entry GlandFor 8 AWG or 10 AWG Cable1View
440A Breaker/Switch, Surface MountBetween Panels and MPPT Charger1View
5MPPT Solar ChargerVictron 100|30 SmartSolar MPPT1View
640A Breaker/Switch, Surface MountBetween MPPT Charger & Battery1View
8Heat Shrink Terminal Ring, 8 AWG Cable, 1/4″ RingConnect to Breakers (Pack of 3)2View
7Heat Shrink Terminal Ring, 8 AWG Cable, 3/8″ RingConnect to Bus Bar (Pack of 3)1View
Alternator
160A Battery-to-Battery Charger (B2B)Sterling Power BB12601View
2100A Breaker/Switch, Surface MountBlue Sea 285-Series2View
3Cable, 4 AWG, 15ft RedWindyNation1View
4Cable, 4 AWG, 5 ft BlackWindyNation1View
6Lugs, 4 AWG Cable, 1/4″ RingConnect to Breakers (Pack of 10)1View
5Lugs, 4 AWG Cable, 3/8″ RingConnect to Bus Bar (Pack of 2)1View
Inverter/Charger
12000W Inverter/ChargerVictron Multiplus 12|2000|1201View
2Remote Control for InverterVictron Digital Multi Control 200/200A GX1View
3Class T Fuse, 300ABlue Sea (To protect inverter’s cable)1View
4Class T Fuse BlockBlue Sea (Holds the Class T Fuse)1View
5Cable, 2/0 AWG, 5 ft Black + 5 ft RedBetween Inverter/Charger & Bus Bars View
6Lugs, 2/0 AWG Cable, 5/16″ RingConnect to Inverter/Charger (Pack of 5)1View
7Lugs, 2/0 AWG Cable, 3/8″ RingConnect to Bus Bar (Pack of 5)1View
830A Shore InletFurrion 30A Marine Power Smart Inlet1View
930A AC MainBreaker Between Power Inlet and Inverter/Charger1View
1110/3 AWG Triplex AC Marine WireBetween power inlet & inverter/charger1View
12Lugs, 10 AWG Cable, #8Connect to AC Main (Pack of 3)1View
13Lugs, 10 AWG Cable, #10Connect to AC Main (Pack of 3)2View
14120V AC Distribution Panel (4 Positions*)Blue Sea Panel: AC Main + 4 Positions*1View
156/3 AWG Triplex AC Marine WireBetween inverter/charger & AC distribution panel1View
16Lugs, 6 AWG Cable, #10Connect to distribution panel (Pack of 10)1View
17120V AC Wall OutletGFCI, 20A1View
1814/3 AWG Triplex AC Marine WireTo wire load that requires 15A or 10A breaker1View
19Lugs, 14 AWG Cable, #8Connect to distribution panel (Pack of 3)1View
20Lugs, 14 AWG Cable, #10Connect to distribution panel (Pack of 3)1View

Optional Items

150A Breaker (Double-Pole)To upgrade 120V AC distribution panel to 50A instead of 30A View
220A BreakerFor load that requires 20A breaker (e.g. A/C) View
310A BreakerFor load that requires 10A breaker View
4120V AC Distribution Panel (6 Positions*)*6 Positions panel is sometimes cheaper, check it! View
512/3 AWG Triplex AC Marine WireTo wire load that requires 20A breaker (e.g. A/C) View
6Lugs, 12 AWG Cable, #8Connect to AC Main (Pack of 3)1View
7Lugs, 12 AWG Cable, #10Connect to AC Main (Pack of 3)1View
Hardware
18 AWG Black/Red Duplex Cable (8/2), Ancor Marine Grade100 feet1View
210 AWG Black/Red Duplex Cable (10/2), Ancor Marine Grade100 feet1View
312 AWG Black/Red Duplex Cable (12/2), Ancor Marine Grade100 feet1View
414 AWG Black/Red Duplex Cable (14/2), Ancor Marine Grade100 feet1View
516 AWG Black/Red Duplex Cable (16/2), Ancor Marine Grade100 feet1View
6Heat Shrink Terminal Ring, 8 AWG Cable, #10 RingTo connect to Fuse Block (25 Pack)1View
7Heat Shrink Terminal Ring, 10-12 AWG Cable, #8 RingTo connect to Fuse Block (25 Pack)1View
8Heat Shrink Terminal Ring, 14-16 AWG Cable, #8 RingTo connect to Fuse Block (25 Pack)1View
9Heat Shrink Butt Connector, Ancor MarineTo connect to Loads (75 Pack Kit)1View
10Heat Shrink Disconnect, 10-12 AWG Cable, 1/4″ Tab, Female
To connect to certain loads (i.e. 12V Sockets) , to make “removable” connections (i.e. Fridge, LEDs) and to connect cable of different gauge together (i.e. LED Dimmer) (25 Pack)
1View
11Heat Shrink Disconnect, 10-12 AWG Cable, 1/4″ Tab, Male1View
12Heat Shrink Disconnect, 14-16 AWG Cable, 1/4″ Tab, Female1View
13Heat Shrink Disconnect, 14-16 AWG Cable, 1/4″ Tab, Male1View
14Heat Shrink Disconnect, 18-22 AWG Cable, 1/4″ Tab, Male1View
153M Scotchlok Quick Splice with Gel (14 AWG stranded)We used that to parallel our LED lights (25 Pack)1View
16Heat Shrink Tubing Kit (with adhesive)To protect lug after crimping1View
17Split Loom Tubing, 3/8″ diameter 25 feetTo protect wire bundles1View
18Split Loom Tubing, 1/2″ diameter 25 feetTo protect wire bundles1View
19Split Loom Tubing, 3/4″ diameter 10 feetTo protect wire bundles1View
20Nylon Cable Clamps KitTo secure cable/split-loom to wood1View
21Zip Tie Mount with AdhesiveTo secure cable/split-loom to metal1View
22Nylon Zip Ties KitTo secure cable/split-loom1View
23Rubber Grommet KitTo protect wire from sharp edge (going through metal hole)1View

3.2- Customize Your Own Wiring Diagram & Items List

You can use our Van Electrical Calculator (faroutride.com/calc) to customize your own system. We’d recommend sticking with a 2000W inverter/charger (you can force the calculator to do so by switching to “manual” mode). For the Nomadic Air Conditioner, use 25Ah current (that’s the average current draw, per manufacturer claim) and something like 8 hours for daily usage. For example:

Image extracted from faroutride.com/calc

In the calculator, scroll down to retrieve your entire items list. Make sure to download the High-Power version of our wiring diagram.

3.3- Managing Expectations

We have to accept how energy-hungry air conditioning is… To make it works off-the-grid, we need to invest in highly-efficient 12V air conditioner but ALSO on a large battery bank. That’s quite a financial commitment.

But yeah, it can be done.

That doesn’t mean you’ll be able to maintain the interior of your van at 68F 24/7 when it’s 95F outside though…

Reasonable expectations would be more, for example, like using the A/C to lower the temperature/humidity just a few degrees, as it can makes the difference between a good night of sleep VS no sleep.

And keep in mind the calculations above do NOT include induction cooking, which is another energy-hungry appliance. “All-electric” builds are very appealing, but keep it real!

Bottom word: manage your expectations and remember that HOW YOU USE IT will have a tremendous impact on your autonomy.

3.4- Variables affecting Energy Consumption

A cooling machine (such as a fridge or an air conditioner) does not constantly work. It cycles between ON and OFF to regulate the temperature. This is called the DUTY CYCLE:

Duty Cycle (%) = (ON duration / Total duration) x 100

For example, if the air conditioner is ON for 1 minute then OFF for 3 minutes, the duty cycle is 25% (1 minute ON per every 4 minutes).

It’s very important to realize that the energy consumption will vary greatly from day to day. Indeed, there are many variables that affect how hard the air conditioner has to work (duty cycle) to maintain a certain temperature:

Installation

Always read the manual and make sure you meet the requirements. For example a fridge evacuates the heat through its coils in the back.  If the fridge is installed in a cabinet without any ventilation, the heat pumped out of the fridge has nowhere to go and the coils won’t be able to do their job.

Maintenance

A heat pump evacuates heat through its coils; if these coils are full of dust, efficiency is greatly reduced and energy consumption increases. Follow the maintenance schedule prescribed by the owner’s manual!

Outside Temperature

The ambient temperature outside has a massive impact on energy consumption. To make an analogy with our fridge, we observed that the duty cycle can get as low as 10% in winter and goes as high as 75% on a very hot summer day. Huge difference!

Inside Temperature

Trying to maintain the interior of the van at a very low temperature will obviously consume way more energy than at a moderate temperature.

Volume

Size matters! It takes much less energy to cool a fridge (~5.8 cu.ft.) compared to a small van (~250 cu.ft.) or a larger van (~500 cu.ft.)

Insulation

Compared to a fridge, a van is poorly insulated and heat transfer rate is way higher. That’s especially true for the windows, so investing in good insulated window covers is a must.

Sun Exposition

Parking directly under the sun is good for solar charging, but quite bad for heat; especially for dark color vehicle…

Opening the doors

It’s normal having to enter/exit the van in our daily life. But each time, a lot of heat is transferred and the A/C has to work harder to compensate.

4- Installation

The Nomadic Cooling Co. air conditioner fits into a “traditional” 14″x14″ cutout; that’s the same cutout as for a Maxxfan roof fan (see our installation guide). We personally didn’t install an A/C on our van, because we’re lucky enough to have the flexibility to follow the seasons (in other words: drive north in summer!). That being said, here are some info to get you started:

4.1- Air Conditioner Adapter

To create a perfect seal and prevent water infiltration, the air conditioner needs to be installed on a perfectly flat surface. The roof of most common van (Transit, Sprinter, ProMaster, etc) have corrugations on them, but the use of an Air Conditioner Adapter Kit that’s model-specific (Transit, Sprinter, ProMaster) will solve that issue:

The roof adapter (gasket) creates a perfectly flat surface:

Air Conditioner Adapter Gasket (Transit, Sprinter, ProMaster)

The kit includes framing strips, to increase support for the extra weight of the A/C:

Air Conditioner Adapter Framing Strips (Transit, Sprinter, ProMaster)

The framing strips are installed inside the van if there is 18″ or more spacing between the beams:

Framing-Strips-for-Roof-Fan-installation-(Van-Conversion)
Air Conditioner Adapter Kit
Select the appropriate variant for your usage (e.g. "AC adapter for Nomadic")

4.2- Resources

Check out Nomadic Cooling Co.’s blog for more information on installation:

Nomadic Cooling Blog

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about us

Nice To Meet You.

Hello! We’re Isabelle and Antoine 🙂 In 2017 we sold our house (and everything in it), quit our engineering careers and moved into our self built campervan. We’ve been on the road since then and every day is an opportunity for a new adventure; we’re chasing our dreams and hopefully it inspires others to do the same!

5 thoughts on “Air Conditioner: 12V Battery Powered A/C for Off-The-Grid Vanlife”

  1. I’m working on installing a Nomadic Cooling 3000 AC unit in our van and am working up wire sizes. The “12V AC” option is not coming up at all on my high powered wiring diagram. Is that feature currently in the PDF file?

    Reply
  2. Thank you for this guide! I’m considering the Nomadic Cooling 2000 (it seems the 2000 is the one with 75A?), but also became curious about the Dometic CoolAir RTX 2000. I can’t find too much info on that one, do you have any insights on it?

    Reply
    • I’m not super familiar with the Dometic unit, but I can see that the roof opening for it is 18.9 in. x 15.3 in. I’d rather go with a “standard” 14x14in roof opening (Nomadic) and use the Adapter listed on the page. Easier!

      Reply
  3. Thank you for this guide! Do you have any thoughts or insights on the Dometic CoolAir 2000 RTX 12V? I was leaning towards the Nomadic 2000 but am now curious about the new CoolAir 2000.

    Reply

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