Solar system upgrade needed for air conditioner?

Hello everyone,
I need real experiences with air conditioning on solar.
I have 4X380w solar panel, 4X100ah lifepo4 battery bank and 1X3kw hybrid inverter.
I live in a sunny area with more than 5hours of sun per day.
I just use my xbox and a tv after work (around 2.5 to 3 hours from 5pm to 8pm)
I would like to know if it's possible to run a 9k to 12k btu air conditionner (mini split or windows) or do I have to upgrade my system?

We need a little more information to give a good answer. But first pass:

• The inverter will probably run (and importantly, start) a 9k just fine. A 12k might be more difficult to start, but it's hard to say for sure. Really depends on the quality of the inverter. My 3500W SRNE (rebranded, but it's a SRNE) would have no trouble with a load like this, but there are lots of stories on this forum of people having trouble starting large loads with less robust inverters.
• If this system isn't running anything else, then you could probably run the A/C for something like 7 hours per day at the very most with those four panels (1500W of panels, 5 hours per day of sun, 1kW A/C load ----> 1500 * 5 / 1000 = 7 hours) . If there are other loads, you'll get less. You almost certainly need more panels.
• Hard to say on the batteries without the system voltage. If this is a 12V system, those batteries would run the A/C for something like 4 hours from 100% full to 0% full. But if it's a 48V system, you probably have enough battery capacity. But not enough solar panels.

Information we could use:
What inverter is it specifically?
What is the dc system voltage? 12V? 48V?

Short answer is you need more.
Depending upon how long you want to run it maybe a lot more!

Most everywhere has sunlight for more than 5 hours... but "sun hours" is a figure based on angle of the sun and duration of direct to indirect solar gain.
In a 12 hour sun day, 1 or 2 hours are direct, and the rest are portions of varying solar output.

Most places not between the tropics of cancer and capricorn average 5 hours... some more some less...

Unless you have all panels tracking the sun, you arent getting much more than 5 hours of strong sun.

LakeHouse said:

We need a little more information to give a good answer. But first pass:

• The inverter will probably run (and importantly, start) a 9k just fine. A 12k might be more difficult to start, but it's hard to say for sure. Really depends on the quality of the inverter. My 3500W SRNE (rebranded, but it's a SRNE) would have no trouble with a load like this, but there are lots of stories on this forum of people having trouble starting large loads with less robust inverters.
• If this system isn't running anything else, then you could probably run the A/C for something like 7 hours per day at the very most with those four panels (1500W of panels, 5 hours per day of sun, 1kW A/C load ----> 1500 * 5 / 1000 = 7 hours) . If there are other loads, you'll get less. You almost certainly need more panels.
• Hard to say on the batteries without the system voltage. If this is a 12V system, those batteries would run the A/C for something like 4 hours from 100% full to 0% full. But if it's a 48V system, you probably have enough battery capacity. But not enough solar panels.

Information we could use:
What inverter is it specifically?
What is the dc system voltage? 12V? 48V?

Click to expand...

Thank you for your quick response.
My inverter is a Sungoldpower 24v3000w hybrid. It runs my waterpump and washing machine with no problem (never tried higher load, never tried to run those 2 at the same time either).
I was thinking about runing the ac at full speed once my batteries are fully charged.
With my current power consumption my batteries are fully charged at around 11 or noon.
My plan was to program the ac to start runing in full speed once my batteries are fully charged (let's say 2 to 3pm) and turn it to eco-mode while I get home as I saw that ac uses less power once the set temperature is reached. I was thinking of runing it till midnight.
Is this reallistic with my current system?

BClimat said:

Hello everyone,
I need real experiences with air conditioning on solar.
I have 4X380w solar panel, 4X100ah lifepo4 battery bank and 1X3kw hybrid inverter.
I live in a sunny area with more than 5hours of sun per day.
I just use my xbox and a tv after work (around 2.5 to 3 hours from 5pm to 8pm)
I would like to know if it's possible to run a 9k to 12k btu air conditionner (mini split or windows) or do I have to upgrade my system?

Click to expand...

Thank you for your quick response.
My inverter is a Sungoldpower 24v3000w hybrid.
I've used it to run my washing machine (6-700 watts) and my waterpump (7-800 watts). However I've never tried to run them at the same time neither have I run higher loads.
My batteries are 12v100ah that form a bank of 24v200ah.
I only use a starlink router during the night that i can either turn off or put on sleep mode if needed.

Supervstech said:

Most everywhere has sunlight for more than 5 hours... but "sun hours" is a figure based on angle of the sun and duration of direct to indirect solar gain.
In a 12 hour sun day, 1 or 2 hours are direct, and the rest are portions of varying solar output.

Most places not between the tropics of cancer and capricorn average 5 hours... some more some less...

Unless you have all panels tracking the sun, you arent getting much more than 5 hours of strong sun.

Click to expand...

Supervstech said:

Most everywhere has sunlight for more than 5 hours... but "sun hours" is a figure based on angle of the sun and duration of direct to indirect solar gain.
In a 12 hour sun day, 1 or 2 hours are direct, and the rest are portions of varying solar output.

Most places not between the tropics of cancer and capricorn average 5 hours... some more some less...

Unless you have all panels tracking the sun, you arent getting much more than 5 hours of strong sun.

Click to expand...

I've monitored my system and it produces around 0.8w at 10am 1k at 11am 1.2k and up from 11am to 2pm then begin to decrease but still produces around 0.6 to 0.7 at 4pm. With my current power consumption (1 starlink router runing all night, a 48in lg C1 and my xbox runing from 5 to 8 pm then the tv only from 8 to 10pm) my batteries are fully charged no later than noon.

BClimat said:

With my current power consumption my batteries are fully charged at around 11 or noon.

Click to expand...

You can think of it this way: Your excess solar power is whatever power you would have made from noon until sundown if the batteries weren't full. You say you're power output is peaking at a little over 1kW, and a 9k btu A/C happens to use somewhere around 1kW, so you could run it for the amount of time that your array makes good power, maybe until 3pm or 4pm.
You could run off of battery power after that, but the next day you won't make enough energy to fully charge the battery, and in a few days your batteries will be dead. You need more solar panels, or you need to plan to use the A/C only with what you currently have for excess.

BClimat said:

My inverter is a Sungoldpower 24v3000w hybrid.

Click to expand...

I suspect this will start the A/C ok, but you'll have to try it out and see what happens.
Given that the system is 24V, the 400Ah of battery should run the A/C at least close to midnight like you're wanting. Note that I'm assuming you have 4x100Ah 24V batteries, and not 4x100Ah 12V batteries wired 2s2p to give 24V.

I have a somewhat similar system. I use a U shaped Midea window AC that is 8000btu. My much older traditional 6000btu AC window unit would occasionally trip up my inverter when it started and other things were being used in the house. My newer midea has never caused an issue. The difference is how the Midea works, which uses some newer tech similar in some ways to minisplits. It can draw anywhere from 400w to 700w depending on the outside temp.

My recommendation would be to try to find something similar. Basically, you want one with a compressor that ramps up and down as needed, rather than just on and off so that it doesn't surge when it first turns on. Just like people use a diversion to heat water when they fill up their battery, I "divert" energy to this AC unit all throughout the day in the summer and it can work a bit into the evening, just like you are suggesting.

I think there are a few other brands that use the same tech. LG was one, but I've seen some Midea clones with different labels. They call it "DC inverter technology" in the marketing.

BTW, if anyone is looking for a way to transition the drain line out of the back of the unit to PVC, this worked perfectly. I added a hose clamp for extra security, but one of the ribs fits right over the PEX rib.

ginmtb said:

BTW, if anyone is looking for a way to transition the drain line out of the back of the unit to PVC, this worked perfectly. I added a hose clamp for extra security, but one of the ribs fits right over the PEX rib.

View attachment 209050

View attachment 209051

View attachment 209052

Click to expand...

Pop the zip tie off, and the insulation fits snugly into a 3/4” coupling.

ANYTHING internal to the factory drain line is a code violation.

Supervstech said:

Pop the zip tie off, and the insulation fits snugly into a 3/4” coupling.

ANYTHING internal to the factory drain line is a code violation.

Click to expand...

So take the pex fitting off and stuff tube wrapped by insulation into a 3/4” PVC coupling and that’s it? Is that watertight?

“ANYTHING internal to the factory drain line is a code violation.“

I’ve seen a number of people use different fittings to connect that hose to PVC. So this is incorrect also? Thanks!

Do you run a refrigerator? How many square ft are you wanting to cool? How tall are your ceilings? What are temps at sunset and sunrise? How about humidity?

You’ll probably want more solar, but give it a shot.

The “U” shaped window inverter AC units do a very good job and a super simple to install. Mini splits are great as well requiring a lot of install time. FYI using a horizontal fan blowing across your bed will really help.

For reference, we run two splits on our system. One 15k btu set at 70-72 degrees plus a Samsung 21.8 cu ft inverter fridge in our one room 1,000 sq ft w-10 ft ceilings and a second 6k split set at 74 degrees in our 110 sq ft w-8 ft ceiling electronics shed (solar gear and 10 cu ft freezer).

We have a 48 volt system. Over the past several weeks, overnight usage with temps of 85 at sunset, cooling off to 50’s overnight has been 160+ amp hours.

We llive in the high desert of Big Bend in the winter/spring. Little humidity, very sunny, no trees and usually hot. We head north for the summer

Best wishes for your project.

ginmtb said:

So take the pex fitting off and stuff tube wrapped by insulation into a 3/4” PVC coupling and that’s it? Is that watertight?

“ANYTHING internal to the factory drain line is a code violation.“

I’ve seen a number of people use different fittings to connect that hose to PVC. So this is incorrect also? Thanks!

View attachment 209080
View attachment 209087

Click to expand...

Yeah, on a horizontal run it could leak... i always connect them with a down slope.

If your drain isnt sloped downwards, seal the connection.

I should also point out the cost. I can occasionally find the Ushaped Midea units on facebook marketplace for $100-150 used. I picked one up on clearance at walmart for $200 a few years ago at the end of summer.

And not only is it more powerful and energy efficient, it sounds somewhere around 20x quieter than my older AC window unit. I can see why people dislike window units if you are looking at something like my older AC unit. This Midea is just in another class.

Jury is still out on the long-term reliability, but has worked well all of two summers so far.