How much solar would i need to run this A/C?

[Helifan93]

Hey guys, 
I know nothing about electricity. I currently have a 90 G30 with no electricity in the living space but im currently working out of the country. im looking into a box truck because I feel like it would alleviate some of my cons on vanlife. but I would want both heat and A/C. ive looked at some options and was wondering if this might be a good idea. I figured I could frame up a false wall a couple feel from the rear doors like I see a lot of people do on box trucks and place the outside part there, with some vents cut into the door. can you guys tell me if im crazy? maybe going down the right path? what if I line the entire top of the box with solar, like 900-1000 watts? 

https://www.alpinehomeair.com/viewproduct.cfm?productID=453077954

 

[1shemp]

No.

 

[rvwandering]

Check out Bob's video with forum member Jim in Denver "YES--Air Conditioner off Solar!! IT CAN BE DONE!"  -

 

[abnorm]

The OP is asking about a 240 volt unit

 

[Giuseppe Hardblast]

While we are on topic. I've been planning out my system build and was wondering myself if an A.C. would be possible.

I would have 1200w with 4 battleborn batteries at 24v (225ah)

I was thinking of taking out the microwave and replacing it with the smallest window A.C. unit I can find.

What do. You guys think of this idea?

I currently only have 500w of solar and 2 battleborn batteries right now.

 

[bullfrog]

From what I've seen and read if you have very much space at all and less than several inches of insulation and want to stay in an area of the country where temps are above 85 degrees and keep inside temps at or below 72 degrees like many people are used to doing in a sticks and bricks or in an RV attached to shore power you won't have enough space to permanently mount the amount of solar panels or hauling capacity for batteries unless you use the really expensive latest technology ones.

 

[brahmon]

bob's video with jim led me down the rabbit hole of obtaining the elusive solar ac! success is sweet. thank you bob and jim!!!! (and all the guys that have helped)

 

[Giuseppe Hardblast]

What's your setup?

 

[B and C]

His setup is not enough solar to support a humongus battery bank that never gets fully charged..

 

[brahmon]

lol. yeah it is because i listened to you and took out a few batteries. its now 2000w and 1200ah

 

[jonyjoe303]

On the hurriedyear.com website there is someone who is running an AC on 1000 watts of solar and 780ah of agm batteries, he shows the buildout of his sprinter van and the installation of AC and its performance.

During daytime with the sun out it might be achievable to run an AC with enough solar panels. But at night time I would seriously consider running a swampcooler. On very hot humid days this past summer my 12 volt swampcooler (2 amp)  kept me cool at night, it didnt do much in the daytime.

If you run an AC all night, you will need a generator to replenish your batteries, solar by itself won't do it.

 

[brahmon]

would lithium batteries allow you to run ac all night wihout a genny?

 

[B and C]

With enough battery you can but (here is the big one) you don't have enough solar to support a bank large enough to run A/C all night.

You really need to get a battery monitoring system so you can see that you are chronically undercharging the batteries you have.
Voltage is a very poor indicator of state of charge especially when you see voltage climb to 13.8 and think the batteries are full. They are not, voltage will keep climbing into the 14+ volt range and stay there until amps taper to whatever you have the controller set for. When the amps taper to this point the system drops into float and holds the batteries at 13.2-8 volts. This is when your batteries are fully charged. Until you see these voltages your batteries are never getting a full charge.

 

[Lowdesertpatrol]

Line the roof with 300w+ commercial panels. Try more like 2-3kw. Used thats about $700-$1,000. The biggest most important most priority is to get lifepo4. I would also look at the high efficiency split duct systems.

Of course all this is utterly pointless if you just follow the weather. I can and will never understand NOT doing so. Youre defeating the point of vandwelling. Let that go and you spend much less being free than trying to chase the dragon which IS the point.

In case youre not aware seeing your breath in the morning in july is quite easily obtainable.

 

[B and C]

The most important priority is to have enough solar to replenish the depleted batteries. You can't take out more than you put in no matter the chemistry. It is either that or cut back on the amount of power used.

 

[brahmon]

i guess im buying lithium. lol

 

[Giuseppe Hardblast]

With enough battery you can but (here is the big one) you don't have enough solar to support a bank large enough to run A/C all night.

You really need to get a battery monitoring system so you can see that you are chronically undercharging the batteries you have.
Voltage is a very poor indicator of state of charge especially when you see voltage climb to 13.8 and think the batteries are full.  They are not, voltage will keep climbing into the 14+ volt range and stay there until amps taper to whatever you have the controller set for.  When the amps taper to this point the system drops into float and holds the batteries at 13.2-8 volts.  This is when your batteries are fully charged.  Until you see these voltages your batteries are never getting a full charge.

What's a good way to monitor lithium Batteries?

 

[B and C]

I don't have lithium, I have agm but the amount of power going in and out can be monitored with a shunt (of sufficient size) and a smart meter to interpret what is happening.  I have a Bogart Engineering TM-2030-RV monitor with a 500 amp shunt.  Not cheap but works very well for me and a lot of other RVer's.  It has a bonus of monitoring the engine battery volts only too.  Others may point you to something much cheaper.  Buyer beware as you hope you get what you pay for.

Bogart Engineering

 

[maki2]

Paying someone to design your system might in the long run save you a lot of money while delivering what you need. It can then be designed to exactly fit the space you have. So can the battery setup and the AC setup.

But first step if you do your own design or hire it out is to take careful measurements and create some lovely measured drawings using a free CAD software program. Do not try to think it all out in your head by keeping on guessing if this solar panel or that will work. Use a CAD program, save out variations of layouts of solar panels and battery banks. Eventually you will figure out how to fit the most solar you can get up on the roof, then create the battery layout. Then after that is all done shop for an AC that can be run off of it as well as fit into your space.

Right now you are going about it in the wrong order by deciding on the AC unit first. It takes less energy to run AC. Heating can be done other ways if needed so while it might be handy to have a combined unit don't start off by thinking you MUST have a combined heater and AC. I could work out that way or it could be that heat is what you need to remove in order to find that one AC that will run off of solar as well as fit into the space it needs to be located in.

 

[Helifan93]

Thanks for the responses guys, that was quick. ill check out the video link someone posted, I was just thinking it would be nice to have a 2 in 1 set up, I was hoping to find one of those diesel heaters that run for hours and hours on 1 gallon, but after watching youtube and seeing that brad guys entire solar that would be nice. I want both because im looking at a job that has me working 2weeks on/off and would love to bounce around and visit family and friends around the country and see the sights in my 2 weeks off since im a single guy and my only hobby would be spending all my money building a CJ7. once again, love the knowledge going around this site