PV Gap

Adrian Said:

Can 2 9-volt batteries in parallel be recharged from a 12 volt solar panel?

We Answered:

It works well to charge any voltage "below" the voltage of the photo cell. It is best to either build of buy a charge controller for the voltage you want to charge - that will keep you from overcharging your 9V batteries. (The other answer is correct - two 9V batteries in parallel = 9V) That is how I would set them up, in parallel. If you put them in series they will be 18V and IF the solar cell puts out 20V (which most do - even those marked "12V" unless they have internal regulation which most don't! ) you could still use the solar cell to charge them - just build a controller for 18V instead of 9.

You can just put a 9V - 10V voltage regulator in the circuit to assure you don't overvoltage them if you charge in parallel but building a charge controller is really a better solution as it will not overcharge them!

Keith Said:

how can you tell the difference between 12 volt solar and a 24 volt panel?

We Answered:

There should be a sticker on it saying what it is. Sometimes it's actually molded into the plastic. If the sticker's gone, stick it in the bright sun & hook up a voltmeter up to it.

Joseph Said:

Need diagram on how to hook up a voltage regulator to a 12 volt solar panel so I don't cook the battery.?

We Answered:

Most regulators will have 3 leads
A.positive input from the panels
B.regulated output to the batteries
C.common ground.

For currents less than 1 amp,a cheap regulator to use is available from Radio Shack. Look up LM7812 regulator.

Franklin Said:

12 volt solar panels for caravans-realistically what wattage would I require to run lights,TV etc?

We Answered:

Its fairly easy to work out.
First work out how long you want each 12v thing on for each day.
Then work out the watt/hours - multiply the watts by number of hours used.
Add all your watt/hours together to give you total watt/hours.
In the UK we get about 8 hours usable light for solar panels. so devide your total watt hours by 8, to give you a guide to the power of solar panel you need. Always go up to the next nearest avaialble size.
For larger size panels you will need a regulator device. - good dealers give good advice. And contary to previous answers you can charge lead acid batteries via solar panels.

Allison Said:

Where can I buy 6 to 12 volt solar panels?

We Answered:

In my experience Jameco Electronics is a fair place to get something like this, if you are in the usa. They strike a nice balance between affordable and quality.

www.jameco.com

search on solar cell

Terry Said:

How can I charge a 12 volt battery with a 10 watt 12 volt solar panel.?

We Answered:

You have not provided enough information to allow the question to be properly answered. If the pump is rated at 9 Watts and runs for 50 minutes, every hour, the solar array will not be able to charge the battery. If the pump ran for 1 minute in every hour, the solar array could possibly charge the battery. In any case, if the battery is a lead-acid car battery, its voltage is 13.2 Volts. The solar array would have to have an output voltage that exceeded 13.2 Volts in order to charge the battery. A sad fact of life is that you cannot grab a handful of bits-and-pieces and cobble them together in the hope that they will work --- when "mixing and matching", you have to do a lot of matching.

Dawn Said:

how long would a 12 volt solar panel take to charge a 100 amp batterie?

We Answered:

1)
A 12-volt, 100 amp-hour battery, fully charged, = (12)(100) = 1200 watt-hours of storage capacity.

Let's say, for example, that you purchased a $ 85, 55-watt panel from this source:

http://www.wholesalesolar.com/

The time to charge your battery to its full-charge capacity (1200 watts) = 1200/55 = 22 hours.

Please remember that this is 22 hours of DIRECT sun, full intensity (10 am - 3 pm) on the panel.

Hope this helps.

2)
I see your previous question identified the devices you wish to power as "a tv, light, and xbox 360".

My friends who live in small cabins "off the electrical grid" -- or in a treehouse -- just use their 12V system to power portable devices. For example, a notebook computer with DVD drive can substitute for a tv. My friends use battery-powered camping lights for all lighting.

Portable devices are far less power-hungry than their 120v-AC-powered relatives. Portable devices either work directly from 12V, or they only need a small inverter to power a charger for their batteries.


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