Solar power forecast for January RTR

[frater secessus]

We can make some wild-ass guesses predictions about how our solar configs might do in Quartzsite in January.

Using the following information:

• 3.25 hours of Full Sun Equivalent for flat mounted panels from this chart (phoenix was closest)
• an average high of 66F (18.89C) ambient / 50.14C cell, giving us 12.06% temperature derating from this calculator

we get an adjusted FSE of 2.86.

Multiply 2.86 x {your rated solar panel wattage} to get daily panel output in Watt/hours.

Multiply that times the efficiency of your charge controller.  ~95% for MPPT?  80% for PWM + poly?  75% for PWM + mono?

Divide by 13 or whatever watts-to-amps constant you prefer.

example

200w renogy poly panels
2.86 adjusted FSE x 200w = 572Wh
13 for W/A divisor

Assuming half of the power leaving the controller is used to charge lead acid batteries and half for loads, we should derate by another 5% for charging losses.

572Wh * 0.95 MPPT efficiency = 543.4Wh  (41.8Ah, or 39.71Ah after charging losses)
572Wh * 0.80 PWM efficiency = 457.6Wh (35.2Ah, or 33.44Ah after charging losses)

I did this mainly to figure out what mine might do there:  114.17Ah daily production.  I tried to do this for Jim's system but the calculator expressed his system's power output as "several lightly populated galaxies".

 

[RVtrek]

I've gotta admit, that's an impressive amount of work that went into trying to figure out how much solar we'll be able to actually pick up. Thank you for the effort you put into it!

 

[DangerBird]

I was at the RTR last year. I could easily make 50AH of power with my 2-100W mono panels on a sunny day. Panels are ground mounted and I chase the sun with them. 20AH on a few of the overcast days we had. Just running LED lights, water pump, fridge propane solenoid(120ma) and charging 2 tablets, 2 smartphones plus a few ham radio HT's. Batteries are 2 group 24 costco deep cycle batteries in parallel, 2 years old and going strong but I take care of them. FWIW.

-Mike