Making sure my calculations are correct

[nathansl2003]

I am brand new to solar, and due to the spread-out nature of my farm, I need multiple off-grid solar units (unless somehow I can connect them).

Here is one scenario I am looking at:

Powering (4) 50-watt chicken brooder heaters. The amps are .45A each, so each would run at 111.11V (this makes sense). 120V AC

If I wanted to continuously run these heaters 24 hours per day at 50W each that is 200W per hour:
That means that 200w x 24 = 4800w of power use each day. Does this mean I need at least a 48V 100ah battery minimum (or equivalent V/A ratings) to run these continuously? the heaters are AC so I would need a converter to convert DC to AC as well.

I was looking at the kits and would need at least a 4.8KW system correct? Something like this https://www.mobile-solarpower.com/48v-complete-system-blueprint-559371.html

In this example, I am not including any reserve for not being able to charge every day.


Thank you all!

 

[sunshine_eggo]

I am brand new to solar, and due to the spread-out nature of my farm, I need multiple off-grid solar units (unless somehow I can connect them).

Here is one scenario I am looking at:

Powering (4) 50-watt chicken brooder heaters. The amps are .45A each, so each would run at 111.11V (this makes sense). 120V AC

If I wanted to continuously run these heaters 24 hours per day at 50W each that is 200W per hour:
That means that 200w x 24 = 4800w of power use each day. Does this mean I need at least a 48V 100ah battery minimum (or equivalent V/A ratings) to run these continuously? the heaters are AC so I would need a converter to convert DC to AC as well.

Wh is a great way to normalize energy needed. Your math checked out. EXCEPT your units are wrong. W is power. Wh is energy.

I was looking at the kits and would need at least a 4.8KW system correct? Something like this https://www.mobile-solarpower.com/48v-complete-system-blueprint-559371.html

No. You need a 200W system - actually 600W. W is power. Wh is energy. You don't need more than 200W at any given time. I indicated 600W because 600W inverters are most efficient around 1/3 rated power.

Compare a 6000W inverter with a 600W inverter...

In this example, I am not including any reserve for not being able to charge every day.

Correct. You are assuming you power it by battery for 24 hours and then it's dead.

 

[nathansl2003]

@sunshine_eggo
Thank you! I thought I had something wrong here, that seemed like a lot of power/money to power 4 50W heaters. I will go back and review the beginner videos on solar to make sure I have the correct calculations in the future.

Nathan

 

[sunshine_eggo]

@sunshine_eggo
Thank you! I thought I had something wrong here, that seemed like a lot of power/money to power 4 50W heaters. I will go back and review the beginner videos on solar to make sure I have the correct calculations in the future.

Nathan

Not that it's not time well spent, but this is a pretty easy thing... Link #1 in my signature - see how much solar is available in your area with PVWatts and run the energy audit.

Quick numbers:

200W 24/7
4h insolation/day

200W * 24h = 4800Wh

4800Wh / 4h = 1200W of solar panels.

Now the decision is 12, 24 or 48V. Due to the size of the array, 24V is probably the most practical.

Are there direct DC alternatives - eliminating the need for DC to AC conversion?