Here we are, in the summer. Time to revisit our calculations on power consumption for our planned solar installation. Here is the usage data, combined with temperatures for the month.

  • January: Average use was 27kwh per day. Average Temp 60 degF, High 82 degF, Low 35 degF
  • February: Average use 27kwh per day. Average Temp 61 degF, High 87 degF, Low 37 degF
  • March: Average use 22 kwh per day. Average Temp 69 degF, High 89 degF, Low 43 degF
  • April: Average use 20 kwh per day. Average Temp 71 degF, High 92 degF, Low 48 degF
  • May: Average use 36 kwh per day. Average Temp 79 degF, High 98 degF, Low 63 degF

You can see that electric use varies with the temperature. The hot months of summer are going to be more costly in terms of electrical use, but that is somewhat offset by more daylight hours. I will continue using the estimated figure of 48 kwh per day. If we assume an average of 6 hours of peak daylight per day, then we need to be generating about 8 kw per hour of daylight. Since I am pricing out 9.6-10 kw of capacity, I think that I am right where I need to be.

Now I need to figure out how much battery capacity I need.

Categories: Electric and Power


IcyReaper · June 1, 2024 at 9:31 am

Will be interested in the end result, am looking at solar myself for the future, if we have one.
BTW, will you be continuing the preparedness topic? I’m curious as to your medical choices of the pyramid.

    Divemedic · June 1, 2024 at 9:59 am

    I was planning on it.

      IcyReaper · June 2, 2024 at 12:26 pm

      Thanks brother, we may not always agree on subjects but I do listen and respect your opinions.
      Wish the rest of the country would do more of that….

Exile1981 · June 1, 2024 at 5:19 pm

Batteries – At our work sites we plan on 72hrs of battery capacity for critical systems and 48 for non critical. If that helps.

D · June 1, 2024 at 5:54 pm

I have three, and it’s more than my panels can charge in a day because I have a pretty high load 24/7 in my office. Lots of servers. They drain to 40% and I’ve only ever seen them as high as 70%…but the system has been in since November and so far there hasn’t been any solid days of sun.

I mainly use the batteries for a bit of a buffer since they are expensive and we always seem to have intermittent clouds/rain. At the peak, I make more than I’m using, but only for a few hours of the day. Their main purpose is for grid outages when solar isn’t available. At 50% they’ll run the office for a solid 6-8 hours…which means 2 AM power outages aren’t a problem. No more waking up to fire up the generator.

Dan D. · June 1, 2024 at 8:22 pm

Evidence based medicine meets evidence based engineering

GUY · June 2, 2024 at 8:41 am

You and Bayou Man are working on the same problem.

Electricity Load

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