Solar Power for Backup when the power is out?

It is still a long way from being the end all for your power consumption, sorry but that is a fact you can not escape.

With the push for 'green' going on lately have you considered using 'Solar Power' for your backup power supply?

There is a misconception about it, solar arrays can not supply the amount of electricity you need for everyday living. What you can do with it is charge batteries or tickle a small amount to help with the load, it is not a replacement energy source.

For everyday use you would need an array that covers at least 3000 square feet, and not many homes have that much usable roof space.

Most solar power installations either trickle the power to the local power gird or for those applications that are backup power tickle charge a battery array.

If you wanted to have a true uninterruptible power supply it has to last more than ten minutes to a couple of hours, would you not? Batteries last only so long. And wind power is only good when the wind blows constantly.

No the only true free (well almost) power is the Sun. But unless you live in Antarctica for eight months and the Artic for the other four months you typically only get 12 hours of sun light.

So how would you have true uninterruptible power with solar? One way would be to have a solar panel (array) that would supply your power during daylight and charge batteries for use after dark. This is the typical setup for a true solar power source.

Ah, but you say how much? Well it ain't cheap! If you are only concerned with emergency contingencies such as a power outage during the day, or your car breaks down on the road in the middle of no where, or you are a camper then there are portable solar power arrays that are light, produce some power, and cost effective.

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You sitting down? Remove sharp objects from your hands - $40,000. Ya, forty K bucks! Whoa! (cost of a solar power array in 2012!)

Where I live and with the roof area on my house I can produce 8 Kilowatts a day! Yes, twice what I use a day during the summer (Air Conditioners draw a lot of power!) so instead of it costing me say $45 a day to cool this house I could be getting paid by the electrical company and have the house cool. But the 40 K has me stumped at this time. I can see the advantage but the outlay is worth a quarter of the cost of the house, when it was NEW!

Back to the emergency or portable Solar Power supply.

You can buy one that is on a back pack with a Battery and Battery Charger and battery that will store the power until you need it to charge or operate a low wattage device such as cell phone, mp3 player, but not your laptop.

If you need more power then you will need a bigger solar panel. And if you need the power at night then you will need a battery (or an array of batteries - my RV has four 120 AMP Marine batteries...) to store the power you collect in the day time. Some of the bigger solar panels produce enough power to convert it to AC (you would use an 'inverter' to change the DC to AC, cheaper to run but cost more to purchase!) than a gas powered generator and usable in some areas where the gas generator isn't allowed.

These are the arrays I have found that make sense -

Note: These prices are from 2009, some brands cost less, some more, research will assist you in getting the best product for the best price.

So lets have a look at them -

Solar Battery Charger puts out: Watts 22.5 @ 1.5A, with the Charge Controller will trickle charge a battery.

The Amorphous 12Volt Solar Panel: puts out 7 Amps at 15 watts. This is for heavier applications such as keeping your car/rv/golf cart battery charged. Will run small low wattage devices and requires a 'Charge Controller'. With an 'inverter' two of these panels will keep a couple of 15 Watt appliance happy with power all day.

The Voltaic Solar Charging Backpack: puts out 1 watt at 100mA, very low trickle charge. Will charge a small battery or power small devices, not good for a laptop.

Both the Solar Battery Charger and Amorphous Solar panels will supply enough power for small appliances such as trickle charging a 12V battery, a laptop, a CB radio. If you need more power you can add more panels to get more power. At $150 - $200 for the panel and charge controllers the cost for a modest array to power more devices or higher consuming devices such as a small refrigerator.

I don't see any use for the back pack solar other than charging your cell phone or mp3 player. Might be good for those that go on long weekend hikes to the wilderness to keep their cell phones charged. (It would be cheaper to buy an extra battery and carry it with you, if you took the battery out of the cell phone until you need to use the cell phone this will help, if the battery is out of the phone it will not discharge...)

There are larger solar panels available but those would not be portable, they require a solid frame and may not travel very well if exposed. I checked on two different products produced in here in Arizona that are useable on a Recreational Vehicle but the cost is high and only one didn't require storage when the RV was in motion.

So if you want to power more than a small low wattage device you have to add more solar arrays. If you have one array that delivers a certain wattage per hour just divide the total wattage by the solar panel's wattage and that will give the number of panels you will need in your Solar Array to power the device all day.

You could also do the same with your battery back up system, most batteries are rated in Ampere Hours.

So to arrive at the desired wattage you would take the Amp Hours and divide that by the voltage to arrive at the wattage.

Such as your 12 volt battery is rated at 600 AH, 600 multiplied by 12 is 7200, so the battery can supply 7200 watts for an hour. So if you need say 150 watts your battery will last approximately 4 and a half hours, two batteries will last 9 hours. Not to shabby but you will have to lug around two batteries...

• P = Watts
• I = Amperage
• V = Voltage
• I x V = P
• 600 x 12 = 7200

One solar panel that supplies 15 watts with a max amperage of 7 amps will give you 2.14 volts.

• P = 15
• I = 7
• V = ?
• P / I = V
• 15 / 7 = 2.14

To achieve 12 Volts continuously you would need six panels 2.14 x 6 = 12.84 Volts. Or a panel that supplies more wattage, which in turn makes the panel larger.

Or

• P = ?
• I = 1.5
• V = 15
• V x I = W
• 15 x 7 = 22.5

To achieve 300 Watts from this type of solar power panel you would have to have 13 panels, however if you have three batteries and two panels you could have power in the day along with trickle charge the batteries during the day and have plenty of power at night.

Solar panels are increasing in efficiency continuously and the future is bright for solar energy production.

I have to put a crimp in your free energy plans, do to mis-management most of the companies in the USA have stopped R&D of the silicon chips so at this time we are dependent on the older technology that was sold to China, there maybe some new chips in the future but at this time we are stuck with the old technology...

Update 02/15/14 - When I wrote this Solar Power article in 2010 there was a push for the "green" energy, wind, solar, the renewable energy sources. But as with any endeavor once the government gets involved so do the thieves. With over $10 Billon to use for R&D we got nothing in return. All companies that jumped on the "green" band wagon took the money then went bankrupt. To top it off those companies in the USA that produced solar panels have been hit by the EPA with new regulations that prohibit making some of the chips, they have also gone out of business...

Update 02/15/20 - The hoaxers are still at it, even with the proof above you can still be swindled by the thieves out there promising the sun and giving you the moon on a moonless night. The technology is still not good enough to give you the power the thieves are promising. Due to the previous administration's policies the mining of "rare earth metals" in the USA has stopped, these metals are required to make the solar conversion from sunlight to electricity, no metals = no innovation or research and development. At this time there is NO company in the USA doing the R&D, the EPA rules of yesteryear are still in place. Beware of the hoax and hype, after all it is your money...