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Old 05-01-2018, 11:01 PM   #1
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Solar powered A/C

Hey Everyone,

I see the question from time to time of running air conditioning from solar. The consensus is that it is, for the most part, impractical.

I have, however, seen a few interesting exceptions. Here is one that I found interesting :http://forum.solar-electric.com/discussion/350889/automatic-control-of-off-grid-mini-split-a-c#latest
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Old 05-02-2018, 05:04 AM   #2
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Hey Everyone,

I see the question from time to time of running air conditioning from solar. The consensus is that it is, for the most part, impractical.

I have, however, seen a few interesting exceptions. Here is one that I found interesting :Automatic control of off grid mini split A/C — northernarizona-windandsun
I intend to run a mini split off solar, like my mentor Juan:
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Old 05-02-2018, 07:52 AM   #3
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Not practical compared to most noobie expectations.

If you know what you're getting into, have the roof space and are willing to both live within limitations and spend a lot up front, no problem.
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Old 05-02-2018, 09:08 PM   #4
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Most would say a generator running an ac is cheaper, in the long run, even with the cost of fuel, at least at the moment.

I suppose if one wanted to spend $10k plus on a solar powered electrical system, one could run an ac unit most of the time.

How many watts of panels do you envision?
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Old 05-02-2018, 10:34 PM   #5
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In clear sunny climate 800W is just enough to run (some, small) aircon from panel output directly.

1200 would give your bank some recharging.

Doubling that would help with cloudy days and ensure you can get your bank to true Full.

But even with 1000's of bank AH, running the aircon **off the batteries** for more than a few minutes, is just time-shifting when you have to start the genny.

So may as well run aircon directly off the genny.
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Old 05-03-2018, 07:00 AM   #6
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How many watts does a bus sized mini split use when running?
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Old 05-03-2018, 08:54 AM   #7
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How many watts does a bus sized mini split use when running?
I am considering this 12K BTU mini split.

The spec sheet for this and other Pioneer mini splits is here. For the 12K 120V mini split the spec sheet says between ~500-1600W (~1100-1200W nominal).
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Old 05-03-2018, 10:33 AM   #8
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2000W of solar panels would correspond to the 800W outlined above as a minimum starting point for 5k BTU, for running off the panels only during peak solar conditions.

Call it 3kW panels to cover suboptimal insolation, and (some) concurrent bank recharging.

And sophisticated soft-start add-ons would likely be required for startup load levels.

And forget about running from batteries, even just a few hours' worth would weigh like a ton.
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Old 05-03-2018, 11:17 AM   #9
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Originally Posted by john61ct View Post
2000W of solar panels would correspond to the 800W outlined above as a minimum starting point for 5k BTU, for running off the panels only during peak solar conditions.

Call it 3kW panels to cover suboptimal insolation, and (some) concurrent bank recharging.

And sophisticated soft-start add-ons would likely be required for startup load levels.

And forget about running from batteries, even just a few hours' worth would weigh like a ton.
FWIW, some, many (most?) mini splits have inverters to modulate outdoor unit fan speed. This feature also enables a soft start or ramp up of current draw.

Skip ahead to the 10 minute mark of this video more on this ramp up. Of course my hero Juan will be running his mini split off ~24kWh of lithium, a 5kW Victron inverter and a butt load (~3600W?) of solar...
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Old 05-03-2018, 05:25 PM   #10
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As above, If you know what you're getting into, have the roof space and are willing to both live within limitations and **spend a lot up front**, no problem.
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