PV Gap

Dustin Said:

What is the difference between Photovoltaic Electricity and Solar Panels?

We Answered:

Photvoltaic makes electricity.

Solar panels makes hot water.

Cathy Said:

What capacitor should i use to store energy from a solar panel?

We Answered:

There are two things to consider with capacitors:

1) The voltage rating
2) The capacitance

The voltage rating tells you the maximum voltage that can be applied across the capacitor. If you exceed this, you'll destroy the capacitor. For storing energy from a solar cell, you just need to check the voltage output by the solar cell under sunlight (using a voltmeter, or by checking the spec sheet for the cell if you have it), and choosing a capacitor with a voltage above the value output by the cell.

The capacitance tells you how much charge is stored per volt applied across the capacitor. So a 1uF capacitor stores 1 millionth of a coulomb per volt applied across it. Once you've made sure that you have a capacitor with a high enough voltage rating, you basically want to pick the capacitor with the biggest capacitance value. From smallest to largest: pF (pico-farad), nF (nano-), uF (micro-), mF (milli-), F, kF (kilo-). You can look up the terms (pico, nano, micro etc.) to see what each of them means.

The energy stored in a capacitor is given by:

E = (1/2)*C*V^2

Where C is the capacitance and V is the voltage applied across the capacitor (not the capacitor voltage rating! Its that voltage that YOU put on the capacitor). The higher the voltage the better, but that will be a fixed value based on the solar cell you use.
The size of the capacitor that you use in the end will depend on what you're actually planning to power with it. If its just for demonstration purposes (say, powering an LED or something) then you can use a very small, cheap capacitor (look for something in the 1000's of uF range). If you're really wanting to power some hefty equipment, then you'll need a bigger capacitor (in the 1 - 1000 F range), which are quite expensive. Here's an example:
http://www.goldmine-elec-products.com/pr…

Kent Said:

how many or what wattage of solar panels do I need?

We Answered:

There are lots of sites and publications (from the government and from companies who sell solar panels, as well as from many electric utilities) that have this sort of information. Here are some that I think are most useful:

http://www.solarexpert.com/Pvmodule.html
http://www.autogatetech.com/solarpanelre…
http://www.101iq.com/solar.htm

Good luck!

Maria Said:

When connecting solar photovoltaic panels to the grid?

We Answered:

The inverter output is tied to your breaker panel. The breaker panel is fed from the meter. You always tie in at the breaker panel so you have a safe method to shut it off and so you have the breaker over-current protection.