Fantasy Van Solar Rig- Over 1kw of panels, 600lbs of batts, and of course, SOLAR A/C

[John61CT]

There is no simple answer there, actual panel output depends on weather, latitude, parking /panel angle and temperature.

Input required for your daily A/C usage depends on temperature and how many hours per day running.

I think you need to work it out this way. Get the most energy-efficient A/C unit that will work for your (well insulated) space. If that requires AC power, add the cost of a big inverter.

Get as large a battery bank as you're willing to give up weight and space and a good SoC monitor.

Get a portable 2000w genny (Honda or maybe Yamaha) and as big a mains charger as you can run on that genny, making sure it has the ability to reduce its current output down in 10-20A increments. That will allow you to choose just charging, vs powering the A/C plus a lower charge rate.

Obviously plug in overnight to shore power to recharge to 100% when you have the chance, you won't be able to do that with the genny.

Otherwise you will need the most efficient watts-per-area panels, maximum to fit your space available.

Run the genny in the morning long enough to get the bank up to 75-90%, depending on the weather, over time you'll get to know the variables.

Use the solar rest of the day to get the bank from there up to 100% full as often as possible, likely requires keeping the A/C off.

If constant heat means the batteries aren't getting to 100% most of the time, then you need to decide between buying the cheapest GC2s (<$1/AH) and replacing them relatively often, or using a more expensive chemistry designed to handle PSOC abuse, with a side benefit of more **usable** AH per pound.

Firefly Oasis at $5+/AH is the cheaper latter option there, LiFePO4 likely double that and also requiring extra custom infrastructure.

 

[CottonTexas]

I've always wondered the same thing for myself.  Texas has a LOT of sunshine, and earlier research only provided information along the lines of "get a generator," or there's a guy I found way-back that had a 5th-wheel with solar panels that fold out as well as the entire roof covered with them, and he was running a small window-unit, but this thread reinvigorated my search where I took a bit different approach, and discovered OTR truckers resources for this stuff.  VERY pri¢ey, but Cruise N Comfort offers 12V A/C systems, and I'm sure there are more companies out there with similar products as well.  Cotton

 

[jimindenver]

Cotton

I have been running a small window unit off of my system for three years now. I ran it pretty much daily for two months in Yuma and Ehrenberg this year. I built the 750w trailer system around the ability to run the A/C at peak sun because that was the rare occasion I needed it where I camped at 10,000 ft in the Rockies. Now that I try to follow the decent weather it may get hot during the day but it's only been hot once after dark so far. I added the 435w tilting panel to the truck so that it can face east in the morning, then south and finally west in the evening, Here in Flagstaff it is a sun hunter as the light comes through the trees, it's 32a certainly can keep the trailer going even if the main system is shaded.

As far as would the 900w system limited to 800w by his 60a controller handle the variable speed A/C, that requires some answers. He has a bigger bank than my 675 Ah and both could handle it over night. The issue is trying to both run the A/C and recharge those batteries the next day. Normally my night time power usage is no where near my day time usage when the solar covers the load most of the time. It takes 33 amps to run the 5000 BTU A/C and the system peaks at 82 amps. That leaves a lot left over for battery charging no generator needed ever. I gave the last one away unused and the one I have now is a SHTF back up that will rot in the back of my truck before I actually need it. Also neither of our arrays would cover the 1100w draw early on until the cabin was cooled down although mine would be taking much less out of the bank at 1185w. Both arrays would be able to replace what was taken once the variable speed A/C dropped to the point of using 300w to maintain temperatures.

So the answer is maybe depending on how much A/C you need. 24/7 at even the lowest draw is 600 Ah a day. Even with a early run of a generator you would be taking a good sized chunk out of your bank nightly shortening its life span. Day time use when the array can cover the load? Day in and day out baby.

 

[sushidog]

The best thing to do is get the most efficient air conditioner you can afford to minimize your solar system and battery bank size and cost.

The most efficient AC available is this Mini-split: http://www.geinnovations.net/Specifications.html You will need eat least 4-12v AGM batteries wired in series to run it as it is a 48v native unit. It only draws 11.5 amps max at 48v or 560 watts to produce 12,000 Btus of cooling. Unfortunately it costs around 2 grand.

If you want to stay with an ac air conditioner, the most efficient is this one: https://www.acwholesalers.com/Mitsu...ser/42447.ac?gclid=CLeentCKkNQCFQsKaQodgcMGVQ it has an SEER of 30.5. Unfortunately it is a 220v system so you will need a 220v inverter. It draws 560 watts to produce 9.000 BTUs The good news it's about half the price of the first one, $1065, but the money you save is eaten up buying the 220v inverter.

The most efficient 110v AC for the money is this one: https://www.highseer.com/ductless-mini-split-heat-pump-wys009am22.html It's only $738, runs off of 110v power, so a regular inverter will work and has an SEER of 22.5 (13.5 EER) and puts out 9,000 Btus from 665 watts, which is about 50% more efficient than a typical window shaker.

I'm planning on installing the first, most efficient 48v unit in a Class A powered by 8 6v GC-2 golf cart batteries wired in series to make a 48v battery bank. I will have between 1,800 - 2,100 watts on the roof (6-7, 300 watt solar panels which will only occupy 22-24 ft of roof length, as I plan to rack them above the vents.) They are very cheap now, dropping to as low as 25 cents a watt from here: http://sunelec.com/ They are B grade panels but come with a 25yr warranty. This will give me plenty of power for other things besides the AC too. A complete system like this will cost me around $5,000 - $5,500 including the 48v inverter charger, controller, wiring, mounting, air conditioner and battery bank (doing all the work myself, of course). But the money it will save me in campground costs (allowing me to boondock more), metered electrical savings and propane costs (as it will provide efficient electrical heat in cool weather too) will pay for itself in 2 years time. The rest is just gravy as they say. The biggest thing I must "budget for" in a system this size is the 1,000-1,100 lbs of weight it will add to the RV.

Chip