Solar air conditioner - battery and panels sizing help

[jezz_maui]

Hi,

I live in Hawaii and I want to run a small window unit air conditioner for about 4 to 6 hours a day in the afternoon only when it is sunny. If it is not sunny then I do not need the air con, I am not interested in running it after the sun goes down. Here are the specs of the air conditioner unit:

Voltage 115
Amps - Cooling 4.5
Watts - Cooling 475
Starting Amps 11.5
Starting Watts 1,322.50

I was hoping someone could help me determine what would be the minimum system requirements to run this air con for a few hours a day. I would need a battery or bank of batteries that are able to deliver the starting watt power of the air conditioner which is 1322 watts. Can someone recommend the minimum battery requirements? If I have say 600 watts of solar panels would this be able to charge the batteries faster that the air con discharges them? The air con uses 475 watts once it is running.

Many thanks!

[Sunking]

Hi,

I live in Hawaii and I want to run a small window unit air conditioner for about 4 to 6 hours a day in the afternoon only when it is sunny. If it is not sunny then I do not need the air con, I am not interested in running it after the sun goes down. Here are the specs of the air conditioner unit:

Voltage 115
Amps - Cooling 4.5
Watts - Cooling 475
Starting Amps 11.5
Starting Watts 1,322.50

I was hoping someone could help me determine what would be the minimum system requirements to run this air con for a few hours a day. I would need a battery or bank of batteries that are able to deliver the starting watt power of the air conditioner which is 1322 watts. Can someone recommend the minimum battery requirements? If I have say 600 watts of solar panels would this be able to charge the batteries faster that the air con discharges them? The air con uses 475 watts once it is running.


Many thanks!

600 watts of panels are not near enough. Try something closer to 1500 to 2000 watts.

[jezz_maui]

600 watts of panels are not near enough. Try something closer to 1500 to 2000 watts.

Ok, how about the battery requirement if I were to install 1500 watts?

[Sunking]

Ok, how about the battery requirement if I were to install 1500 watts?

Minimum size for FLA would be 24 volts @ 500 AH, which is more then you need. You could go with AGM 24 volts @ 250 AH but it cost just as much if not more than the FLA option. If it were me and could find a controller to work with Lithium is a 24 volt 60 AH LFP battery. A 60 AH LFP battery sells on the mainland for around $80 each and you would need 8 of them. Lot cheaper than FLA or AGM, but will not last as long.

[Sunny Solar]

My suggestion dont use a window type air con.. very inefficient.. unless its a new Toshiba inverter.. look for a inverter split type aircon.. much lower start up draw and in most cases lower running current draw

[Sunking]

My suggestion dont use a window type air con.. very inefficient.. unless its a new Toshiba inverter.. look for a inverter split type aircon.. much lower start up draw and in most cases lower running current draw

Good idea and there are 24 and 48 vdc models available that are extremely efficient.

[jimindenver]

I am in the same situation at altitude in the Rockies. We don't often need the air, only a few hours a day, mid summer and only when the sun is shining. I picked up a Frigidaire 5000 BTU energy star unit using 446w on high and was able to run it off of 720w of panel without draining the battery. The panels are portable and have to be kept tracking to do it and when there isn't quite enough power, the drain on the bank is small. I couldn't do it with the panels mounted as the numbers are extremely close tracking. 39a plus the inverter vs 50a max from the solar system. It's a hassle but it's better than running the generator while camping.

Fixed, depending on the orientation of the panels at the time you need the air, will require more panel and a matching sized battery bank. That's going to be a pretty expensive air conditioner to run if you have any other options. Hopefully you can convert other loads to the system when the air isn't needed.