AC On Solar Power

[marbles]

I have a 320 watt solar panel on my 24RKS. It is producing over 20 amps when hot and up to 30 amps in the best conditions.

If I put a slow start device on my AC and it draws a maximum 20 amps on start, can I run it from solar which produces 30 amps?

Am I missing something?

[bansai]

Sorry, but no way realistically. I mean you could do it in theory... but we're talking about a 1000 watt solar system and a massive battery bank and inverter.

Problem is you are taking a 12 volt DC power source and trying to run a 120 volt AC appliance off of it without doing the conversion or accounting for your batteries. Your air conditioner doesn't run on 12 volts. A 20 amp load at 120 volts is 2,400 watts of continuous power. You'll also need a big inverter, which will increase your losses.

Even with 320 watts of (DC) solar panels, you aren't anywhere close to supporting the demands of a 2400 watt AC current appliance for more than a few minutes.

Another way to think about it is this...
People often purchase a generator that puts out more than 3000 watts of 120 Volt power to run their air conditioner. Your solar panel puts out 300 watts of 12 volt DC power under ideal conditions - a fraction of what you would actually need.

Here's a video -

https://www.youtube.com/watch?v=B0rZY5uotKI&t=453s

These guys had a 700 amp hour battery bank (my camper came with a 75 amp hour battery, not sure about yours..) I would just add that the video above has often been called out for being overly optimistic. These guys have a massive system and they were able to run their AC for about an hour before they were risking their very expensive / large battery bank.

[Les7h]

Solar is maybe 18 volts at 20 amps & your A/C is 120 volts at 20 amps
Approx 200 amps to run your A/C ( my numbers are not exact but ballpark ) and would require a large inverter & a large battery bank

[DanNJanice]

As bansai said, you are forgetting about the 1:10 ratio of current to go from 12VDC to 120VAC. So to get 20Amps AC you would need a least 200Amps from you batteries. Now your AC may not need 20 amps continous, but it will still need "a bunch".

[marbles]

I missed the conversion to 120V AC from 12V DC. 20 amps at 120V is 2400 watts and my little 320 watt solar panel won't cut it.

Thank you all. I missed a step in my math. I would need 8 of the 320 watt panels at optimal sun to make it work.

[us71na]

P=IV For your solar panel 30 X 12 = 360 watts

For your A/C 120 x 15 = 1800 watts

You would need at least 5 solar panels if the inverter were 100% efficient in converting DC to AC, which it is not. Any cloud passing by would cause a low voltage situation which would damage your A/C

[rodro123]

Originally Posted by us71na

P=IV For your solar panel 30 X 12 = 360 watts

For your A/C 120 x 15 = 1800 watts

You would need at least 5 solar panels if the inverter were 100% efficient in converting DC to AC, which it is not. Any cloud passing by would cause a low voltage situation which would damage your A/C

The system to run ac would cost over $26,000. You would need 5 300watt panels, a very large inverter, 10 lithium ion battery's 200ah ea. (lithium can be run down by 80% without damage to the battery. Lead acid is only 50%. But the biggest problem is the weight the battery's alone weight is 830lbs. Cost of battery's is $24,000 but that's the only way to go. In 5 years prices will fall by 2/3.

[Seann45]

Look at my signature.. I can run my A/C for 20 min max before it kills my batteries.