PV Gap

Marvin Said:

Solar panels - What can 60 watts do for me?

We Answered:

Well, as long as the sun is shining, you can light 6 or so CFL lights, or a small TV or PC.

But you will need a charge controller, a battery, and an inverter, all expensive. The charge controller regulates and controls the charging of a battery by the solar cells, the battery (use a marine lead acid battery, not an auto battery) stores power for when the sun is not shining, and the inverter converts 12 volts DC to 120 volts AC to operate house appliances.

In so far as the numbers, 120 watts for 12 hours is 1440 watt-hours or 1.44 kW-hrs of energy. You will need two large marine lead acid batteries to store that energy.

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Martin Said:

Solar Panels power help?

We Answered:

What you really need to calculate is your energy requirements, you are only stating your power requirements.

Power (W) = how many watts of power are you using?
Time (h) = how long are you going to use the power for?
Energy requirement(Wh) = W * h

take the answer to that equation and plug it into the exact same equation except substitute how much sunlight you get for h and then solve for W to find what you need in the way of a solar panel.

Wattage of solar panel (W) = Energy requirement (Wh)/hour of sunlight per day (h)

Now you know what wattage of solar panel you need.

For the battery you use a different equation:

Energy in the Battery(Wh) = Battery Voltage (V) * Current Capacity (Ah)

Solving for Current Capacity:

Ah = Wh / V

This will tell you how big a battery you need, but you also need to be concerned about how much current it can source. For this you need to know what your peak power requirement is.

Wmax = peak power requirement

Max discharge current (Amax) = Wmax / Vmax

Also you will need an inverter rated to Wmax as well.