have 2hp aircon,fridge and a 36" flat tv...

BB.BB. Super Moderators, Administrators Posts: 31,337 admin
This discussion was created from comments split from: Comparison between 3 different L16 type batteries..
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset


  • rowelrowel Registered Users Posts: 1
    Hello.. just to ask you guys.. i have 2hp aircon,fridge and a 36" flat tv.. i just to know how much volts do i need to run this appliances. The is 24hrs running,the aircon just only night time let say 6pm-6am. And the others day time. Washing machine is weekly o twice a week only.. is it possible for the off-grid. My plan is the aircon and the fridge run by solar only. Am just asking to yuou guys coz i dont have any idea about this. Im interested this solar..thanks in advance..
  • BB.BB. Super Moderators, Administrators Posts: 31,337 admin

    This is not going to be a cheap system... Are you doing this to save money or to have power where there are no utilities?

    And technically, it is not "volts" that you need to research here (although, it is important), you need to understand how much power (Watts) and Energy (Watts*Hours) you need per day.

    Just to give you some ideas of what you are looking at (made up numbers):
    • 1,600 Watt A/C * 0.50 duty cycle * 12 hours per day = 9,600 WH per day
    • 1.1 kWH per day refrigerator = 1,100 Watt*Hour per day
    • 300 Watts other stuff * 12 hours per day = 3,600 WH per day
    • ==============================================
    • 14,300 Watt*Hours per day
    • just FYI, Monthly power usage = 14.3 kWH per day * 30 day sper month = 429 kWH per month (probably a low estimate of power usage)
    Battery bank.... With 2 days of storage and 50% maximum discharge (for longer battery life):
    • 14,300 WH per day * 1/0.85 inverter eff * 1/48 volt battery bank * 2 days storage * 1/0.50 max discharge = 1,402 AH @ 48 volt battery bank (around 4,600 lbs of lead acid batteries)
    You need a minimum amount of rate of charge... 5% to 13% typical for solar. For full time off grid solar and/or using Fork Lift type batteries, 10% rate of charge minimum recommended.
    • 1,402 AH * 59 volts charging * 1/0.77 panel+controller deratings * 0.10 rate of charge = 10,743 Watt array nominal
    And based on where you live. Say fixed array in Manilla Ph:


    Average Solar Insolation figures

    Measured in kWh/m2/day onto a solar panel set at a 75° angle from vertical:
    (For best year-round performance)
    Jan Feb Mar Apr May Jun
    Jul Aug Sep Oct Nov Dec

    Say a minimum of 4.05 hours a day average sun (December):
    • 14,300 WH per day * 1/0.52 system eff * 1/4.05 hours per day = 6,790 Watt array minimum (December break even month)
    Anyway, just some quick back of the envelope numbers. You would need a minimum of 4-5 kWatt AC inverter to run your equipment (guessing). And, you should have a backup genset (probably 10-20 kWatt as backup minimum--carry you though storms and any equipment failures).

    Does this help?

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave AngeliniDave Angelini Solar Expert Posts: 5,712 ✭✭✭✭✭
    Definitely the OP should update the cooling equipment before even thinking of this. Nice job though Bill
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
    E-mail [email protected]

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