PV Gap

Brittany Said:

How much do you know about going Green?

We Answered:

A lot of those things help, but I mean there's always going to be something that is more energy efficient. The best idea is just to use less.

Rosa Said:

How do you make a Solar Oven?

We Answered:

I would suggest ditching the battery idea, you want to keep it simple and inexpensive... A solar charger is like $70 and a battery is another $100 and then you have to try and get a heating element.

Here is a link with several solar cooker plans, get a dutch oven (cooking pot with lid) to hold your cookie dough and then use the solar oven to heat it up. You can also find a large page sized magnifying glass to focus the solar energy on the cooker to help heat it up.

http://solarcooking.wikia.com/wiki/Categ…

http://www.amazon.com/dp/B000SKLFFG/ref=…

Felix Said:

Question about rechargeable Battery Seaked AGM and watts?

We Answered:

Solar is uneconomic in most real world cases, but fine for a science fair project.

26 amp-hr is the battery capacity or stored energy. It is equal to 1.3Amps * 20 hrs. Voltage varies with discharge rate, temperature, and state of charge. It starts at about 13.2V for a 12V battery, and the battery is quite dead at about 8 or 9V. Power (energy / time) would be average of 11.5V * 1.3A = 15W. 15W * 20 hrs = 300W-hr, or 0.3 kW-hr. My utility charges 8cents per kW-hr, so this is 2 cents worth. Doubling the discarge rate leaves less than half the life. Discharge curves can be found at http://www.unionbattery.com/discharge.ht… For a 300W load at room temp, you need perhaps 26A, which is 1C (1x the 26 A-hr capacity). This would run the TV about 30 min to battery exhaustion. BTW, note that the TV requires an inverter or UPS to convert the 13.2 to 8V battery output to 120 VAC (volts alternating current). This typically uses 20% - 30% of the energy. Also, energy is force x distance or Joule = Newton x meter. Watt = energy/time = joule/sec. For comparison, ideal 1 horsepower motor uses 746 watts. Running it for 1 hr would give 1 hp-hr or 0.746 kW-hr, about 6 cents worth of electricity. Finally, the dashes in the units above means "times" as in multiplication.

You can measure the voltage to get an idea of the charge. If you use the same load all the time, you can accurately record the voltage and the operating time to give you an idea. This will change over time, as the batteries degrade.