PV Gap

Scott Said:

What Do I Need To Convert My House To Solar Power?

We Answered:

Your best return on investment is solar hot water, then superinsulating the house, then photovoltaic.
My rule of thumb is you get about 50% of peak power for about 8 hours a day from a solar panel. Your 83 kWhr/day would require about 21 kW of panels to completely replace your grid power, around $60k at today's prices. Your local power company may have subsidy/buyback policies to bring down the purchase price requirements. Insulation to bring down your A/C requirements will pay you back faster than the PV panels will. We're off-grid, good house insulation lets us be quite happy with less than 10 kWhr/day of solar power.

Emma Said:

Powering laptop with solar power.?

We Answered:

The laptop would stop charging its battery when it becomes full. Otherwise that would ruin the purpose of having a battery on the laptop. If you did your math right and made the convertor correctly to deliever the correct input voltage and wattage / amperage to the laptop. Then yes you can power it through a solar panel. Don't know why they don't have an option to power a desktop through a 12volt source. Propably because it would go through a good size car battery within 2 1/2 hours or so.

Clifton Said:

How much current is needed for inverter?

We Answered:

You size the inverter based on the load, not the solar panel. The solar panel will charge the battery, and the battery will power the inverter. The solar panel does not directly power the inverter. So if you are powering a 10W light bulb, you need at least a 10W inverter. The inverter converts the 12V DC to 120V AC. In doing that, it increases the voltage x10, and decreases the current x 1/10. Watts = volts x amps, if volts goes up, current (amps) goes down the same percentage.

If the panel is outputting 300mA for 5 hours (that's a good summer day), you will make 1500ah. You're going to lose about 30% of power, so you'll actually make about 1000maH. You've got 10 1.2V 1300mAh batteries, wiring them in series will make a 12V 1300ah battery bank, so your panel can about fill it up in a good day.

If you are using 10W AC, that's about 83mA AC (10W / 120V = .083A), but on the DC side, it's about 830mA DC (10W / 12V = .830A). If you run it for 1 hour, you'll use 830maH. You are making about 1000maH a day, so you'll be able to power that 10W load for about 1 hour.

Keep in mind, the panel is outputting up to 300mA, and the load is using 830mA. You are using at a faster rate than you are making.