Beginner, need help sizing solar array and battery size

[jacobp]

Hello all and thank you for taking time to help a newbie. Please forgive my ignorance.

I have watched a good amount of videos on how to set up solar but they’re are some things that just go right past my head.
I have a RV trailer that I live out of and would like to install solar for it.

Based off my generator, with Air conditioning and all my common used electric devices (tv, gaming, WiFi) I pull about 2.2kw of constant electricity.

I was thinking of building the mobile 48v system that Will Prowse made.
Would that be enough power to run my Air conditioner for a few hours after the sun has gone down?
And how much solar power will I need to constantly power my air conditioner while the sun is out and also charge the batteries?

Any help is greatly appreciated.

 

[sunshine_eggo]

2.2kW continuous is about 52.8kWh/day, which is 76% more than the average U.S. household.

That means you need:

about 55kWh of batteries
about 12kW of PV

 

[Rednecktek]

about 55kWh of batteries

AKA 11 of the rackmount batteries, plus one for the inverter's overhead...

about 12kW of PV

Assuming you get perfect clear sun every day...

I pull about 2.2kw of constant electricity.

That number seems really, REALLY high. 2.2kw non stop is 2200w * 24 hours = 52,800wh which at $0.10/Kwh = $5.28/day * 30 days = $160/mo if you were getting grid power. Are you running this all on a generator? That's what, 12 gallons a day, or $50+ a day in fuel?

I think you should do a proper power audit with some Kill-A-Watts and see where you are really sitting on a per circuit or per device end. With an RV trailer you're probably not going to have enough physical space for the batteries you think you need.

 

[50ShadesOfDirt]

Don't know all of your requirements, but the correct answer could be to "ease in" to solar, with Will's 48v system providing as much power as your scenario allows, and the generator making up the rest, or carrying big loads like air conditioning.

In essence, instead of running the gen all the time (24 hours/day) you need power, you may only need to run it to recharge the battery-bank (4 hours/day), when solar isn't carrying the load.

As you can find on other design threads on this site, perhaps start by reducing all loads, and designing for your remaining loads after that reduction.

Hope this helps ...

 

[jacobp]

AKA 11 of the rackmount batteries, plus one for the inverter's overhead...


Assuming you get perfect clear sun every day...


That number seems really, REALLY high. 2.2kw non stop is 2200w * 24 hours = 52,800wh which at $0.10/Kwh = $5.28/day * 30 days = $160/mo if you were getting grid power. Are you running this all on a generator? That's what, 12 gallons a day, or $50+ a day in fuel?

I think you should do a proper power audit with some Kill-A-Watts and see where you are really sitting on a per circuit or per device end. With an RV trailer you're probably not going to have enough physical space for the batteries you think you need.

So I live in SoCal I get plenty of sunlight. I’m still connected to grid power during the day to keep the air conditioner running on low (I have cats and don’t want them to bake) I only run the generator in the after noon when I get home, which is usually around 430pm and shut it off once sun light is not shining on my RV.
I was hoping I could run my AC off solar during ideal sunlight conditions then run off batteries for maybe around 3-5 hours after sunlight is not ideal

Thank you for your help

 

[jacobp]

Don't know all of your requirements, but the correct answer could be to "ease in" to solar, with Will's 48v system providing as much power as your scenario allows, and the generator making up the rest, or carrying big loads like air conditioning.

In essence, instead of running the gen all the time (24 hours/day) you need power, you may only need to run it to recharge the battery-bank (4 hours/day), when solar isn't carrying the load.

As you can find on other design threads on this site, perhaps start by reducing all loads, and designing for your remaining loads after that reduction.

Hope this helps ...

I don’t plan on running off batteries all night. Just enough to power the AC for about 3-5 hours after sunlight is not ideal for the panels. And run AC off panels during ideal sunlight conditions
Thank you for your help

 

[brucey84]

If you want to maximize on daylight first then I suggest getting more solar panels. If 2kwh is your max then I suggest start with 8kw of solar. 20 piece of 400w panels. You will get close to 7kw of solar at peak and close to 2kw on days with low light. I would try to hit 10kwh of batteries, it will get you 4.5 hours of runtime at 1.5kwh of use. You can add more batteries if you need more later. The main factor is make sure to choose the right inverter at the start.