Another Off-grid solar A/C report.
Posted by BaldyCarrotTop@reddit | preppers | View on Reddit | 18 comments
So I thought I'd share my solar off-grid A/C experience. Looks like I'm not the only one with this idea. Alex Beale over at Footprint Hero on Youtube has done a similar thing. And someone else has recently posted a report of a similar setup in this forum. And here I am.
The setup: Built around an Ecoflow Delta 2, 1024Wh power station with a 1800W inverter. Supports up to 600W of solar input. Runs an 8,000BTU Window A/C with a 5.6 Amp current draw. Solar is provided by 3 Used Trina 250W solar panels.
Observations: The Delta 2 has no trouble running the A/C. When running with the fan only it draws 86 Watts. Once the compressor kicks on it draws about 600W.
Solar panels are a bit disappointing. Two of them are mounted on the fence with a hinged mounting frame. Originally I was going to mount all three panels to the fence. But a last minute change to larger panels meant that there was only room for two. The 3rd is set up as a roving ground mount. Currently the panels are producing a steady 370W. Much less than expected. Adding panels won't help. Each panel can produce 195 Watts each. But when combined, the panels run up against the 15Amp limit of the Ecoflow's solar input. I'm thinking of getting a voltage booster.
A typical day: (if there is such a thing). Delta 2 usually starts the day at less than 30% charge. The sun clears the eastern tree line about 8:30 and the Delta 2 begins charging in earnest. Previous to this it has been charging slowly. By about 11:30 the Delta 2 is fully charged. Usually there is no need for A/C in the morning. If there is, I'll just plug it directly into the wall and run it on grid (only had to do this once).
I'll turn the A/C on as it warms up in the afternoon. On very hot days the Ecoflow is exhausted by 4:00. On cooler days, it can last beyond 6:00. If I still need the A/C I'll switch it back over to the wall plug. In any case, solar will start recharging the Delta 2.
Summary: Not quite what I expected. But not bad. I can increase the run time if I could coax some more power out of the panels. I'm going to experiment with a DC to DC voltage booster and see what happens. In the mean time, my calculations indicate that I am harvesting about 2.4KWH per day. Not too shabby.
New-Temperature-4067@reddit
I spent 13k on a home solar setup 5kw of pv panels (11) A 5kw smle3 inverter 2x 10.1 kwh battery bank for 20kw total
From may to september i have free power. In winter a battery lasts a day but is full in 4 hours of sun. I basically only pay for gas now. It also runs in island mode which i can force by flipping the main breaker, it also should do this automatically but i have to wait for an actual outage to test this.
lexmozli@reddit
Can't you put the panels in series? The two of them that is, maybe buy another one so you have 2s2p? Or just buy one single bigger panel. (450-550w)
If budget is not important, a more efficient AC would also help, Ecoflow has it's own (Ecoflow Wave 3). 86w for just a fan is insane, my biggest fan uses about 65w and it blows, it's unbearable to sit in it's direct flow. I usually use my fans on their lowest setting which is 10-25w in most cases.
BaldyCarrotTop@reddit (OP)
No, I can't put the panels in series. They have a Voc that is higher than 30V. Two in series would exceed the Delta 2's 60V input limit.
Budget is important. I'm trying to use as many things as I already have. So, Home Depot special window A/C that I have had for about 6 years.
thomas533@reddit
I know it is what you have, but this is why I don't like the all in one power stations. If one component breaks or needs to be upgraded, you don't have many options.
Building your own power station is pretty easy and I think it is a skill every off-grid person should know how to do.
BaldyCarrotTop@reddit (OP)
Normally I would shy away from the all-in-one solution. But in this case there was a really good Cyber Monday deal. I just couldn't let it pass. I couldn't DIY a similar system for that price. Somewhere on my radar is a DIY, 5KWH, hand truck power station. At that level, I'm DIYing.
If it breaks, meh! To me it's a bunch of parts (inverter, battery, charge controller) I'll just take it apart and re purpose the parts that work.
IsThisNameGoodEnough@reddit
Yep, they can run two strings in parallel. The power station has a max solar input of 60V and the panels have a max power voltage of 30.3V. But since they have three panels they'll need to either drop to a 2P setup or buy another and go 2S2P.
joshak3@reddit
If you're off grid and using this solar setup only for the the air conditioning, what do you use as the main power source for everything else?
shikkonin@reddit
Hence, not off-grid. Just one off-grid system in an on-grid house.
BaldyCarrotTop@reddit (OP)
Correct. Running fans and A/C in the summer really pushes up my electric bill. Since I had this Delta 2, and I could get some solar panels for cheap, I thought I'd try an experiment to see if I could make a dent on my summer electric bill.
And why do I have the Delta 2? 1) Because of a really great Cyber Monday deal. 2) In an emergency, I can use it to run my refrigerator or the forced air gas furnace. 3) I also use it to run the lawnmower in the far corners of the yard where the extension cords won't reach. Thing is earning its keep.
I should also point out that experimenting with it now, and getting the kinks worked out, means I won't have to do this when an emergency hits.
shikkonin@reddit
Adding panels won't help.
Of course it will.
You can still add panels with different orientations to widen the curve a bit. Or you get better batteries.
Which won't do shit.
RedOctobyr@reddit
Seems like a lot of folks speculating with answers on what will or won't help, without necessarily stating why.
Eco Flow lists this for the Delta 2 solar input:
"11-60V, 15A, 500W max"
So yes, increasing input voltage could help, if currently limited by the 15A input limit and the existing ~25V coming out of the panels.
And it can take more input wattage than ~370W, but still can't take the theoretical 685W from the 3 panels. But hopefully you could hit 500W, at least.
BaldyCarrotTop@reddit (OP)
Thanks. You saved me from typing it myself. Pretty much everything you said is correct.
Internal_Raccoon_370@reddit
the OP is getting watts, amps and volts all messed up, I think.
RedOctobyr@reddit
What seems wrong? It looks reasonable to me, the discussion of the panels and limits, etc.
Eredani@reddit
All power banks have voltage and current limits on solar input. Looks like the OP is hitting the wall on those limits. Adding more panels will either do nothing if the power bank can cap the input or damage the unit if it can't.
Running an AC is a very heavy lift for these kinds of systems. You need a robust system with a high solar input capacity and a large battery storage capacity.
PenguinsStoleMyCat@reddit
I've thought about buying/building a battery bank for a while and I could never justify it with the short runtime versus a generator. I bought an EV this year and after buying it I learned that it could do vehicle to load (V2L) up to 1,800w and could use 62kWh of the 77kWh battery pack. I made up a whip to connect it to my generator's inlet and power one phase. I have all of the 120v circuits I care about all on the same phase and can power them with the car.
I have a 120v mini split in my home office, and I estimate it'll use less than 5kWh per day max, but could be less. Just not sure what the runtime would look like if my central A/C wasn't also on. Anyways, at 5kWh I can run the mini split for 10+ days if needed. With the other essential loads I've calculated I could run for about 4 days off the car. That's a nice little bonus to have and in reality I would spin up the generator during the day so I can have hot water, run the central A/C for a bit, maybe stove, etc.
I'm hoping in a few years more EVs come out with robust V2L setups. I know Ford has a nice setup.
BaldyCarrotTop@reddit (OP)
Well, how long it lasts depends on what you are trying to run. In an emergency I'll not be running the A/C. Refrigerator for sure. Everything else will be battery powered devices, camp stoves and heaters. You get the idea. In any case, power management planning should be part of everyone's plans.
ResolutionMaterial81@reddit
I have an Ecoflow Wave, Ecoflow Smart Generator & 2 Ecoflow Delta Max...along with other manufacturer's power banks, panels, etc.
The Wave running on AC power draws approximately 750 watts, but with the direct DC cable only draws around 300 watts!
Massive savings running DC-to-DC.