Easy solar calc.

tabbycat
tabbycat Solar Expert Posts: 55 ✭✭✭
Given that the available load demand of a lead acid battery bank is 50% DOD (20 hour rate) or 500 watt-hours per KWH of bank capacity and a 130 watt panel's output is 500 watt-hours per day (Florida annual daily average) then multiplying the WH bank capacity by 0.13 will give you a good estimate of the size of the solar array in watts needed to replace the load consumption.

Comments

  • CALLD
    CALLD Solar Expert Posts: 230 ✭✭
    Due to the high price of batteries and low price of solar panels I prefer to take the worst month of the year's figures when calculating the size of my array. While this may be more practical for those living at lower latitudes than those living in the extreme north or south it's a safer bet. The weather can be a moody beast sometimes, I'm in the 3rd week now of way below average production and there's still no sign of sunny weather returning any time soon. Solar power is not reliable, it is merely supplements your energy needs when the sun-gods decide to smile upon you;)
  • cupcake
    cupcake Solar Expert Posts: 254 ✭✭✭
    CALLD wrote: »
    . Solar power is not reliable, it is merely supplements your energy needs when the sun-gods decide to smile upon you;)

    Not exactly true - it depends on WHERE you live. The dry half of the country gets nearly 360 days of sun per year, not to mention the other deserts around the world. I live in the desert there's sun every day all day from sun up to sun down... A key of using solar power is to first go somewhere that has solar in the sky and not clouds in the sky... I am on solar year round, it is not 'supplematary' it is 'primary' for me and others out here...

    fyi examples in the USA include, so-cal, vegas, utah, mojave desert, etc
    ~1.5Kw PV in parallel
    Morningstar MPPT-60 controllers (2) in parallel
    3 Trojan tr-1275's in parallel 450ah total
    Samlex 2,000 watt 12-volt inverter hardwired


  • CALLD
    CALLD Solar Expert Posts: 230 ✭✭
    cupcake wrote: »

    Not exactly true - it depends on WHERE you live. The dry half of the country gets nearly 360 days of sun per year, not to mention the other deserts around the world. I live in the desert there's sun every day all day from sun up to sun down... A key of using solar power is to first go somewhere that has solar in the sky and not clouds in the sky... I am on solar year round, it is not 'supplematary' it is 'primary' for me and others out here...

    fyi examples in the USA include, so-cal, vegas, utah, mojave desert, etc

    Well aren't you the lucky one:)

    Where I live partly cloudy weather prevails, sunny weather stretches of more than 3 consecutive days typically comes once a month and overcast stretches of more than 3 consecutive days also typically happens once a month. The best we ever get is maybe a week of mostly sunny weather. The worst stretch I've experienced so far is 3 weeks of persistently unstable weather dominated by overcast skies or mostly cloudy skies. And South Africa is rated as a "sunny" country by world standards...
  • cupcake
    cupcake Solar Expert Posts: 254 ✭✭✭
    CALLD wrote: »

    Well aren't you the lucky one:)

    Where I live partly cloudy weather prevails, sunny weather stretches of more than 3 consecutive days typically comes once a month and overcast stretches of more than 3 consecutive days also typically happens once a month. The best we ever get is maybe a week of mostly sunny weather. The worst stretch I've experienced so far is 3 weeks of persistently unstable weather dominated by overcast skies or mostly cloudy skies. And South Africa is rated as a "sunny" country by world standards...



    You are in South Africa?

    ~1.5Kw PV in parallel
    Morningstar MPPT-60 controllers (2) in parallel
    3 Trojan tr-1275's in parallel 450ah total
    Samlex 2,000 watt 12-volt inverter hardwired