With a little thought and preparation, you can solve many of your electrical needs safely in the event of an extended power outage. The do-it-yourselfer might want to make their own portable solar power supply, or put a 12 volt motor in a small swamp cooler to solve those electrical needs.

Safer Backup Power With Solar - Using The Sun For Emergency Preparedness

Michael Little | Vegas Trailer Supply

Safer Backup Power with Solar

With a little thought and preparation, you can solve many of your electrical needs safely in the event of an extended power outage. The do-it-yourselfer might want to make their own portable solar power supply, or put a 12 volt motor in a small swamp cooler to solve those electrical needs.

By Michael Little
Vegas Trailer Supply www.vegastrailer.com

August 14th was an eye opener for the 50 million people who were victims of the largest blackout in US history. I was amazed when CNN interviewed a man who was the hit of his neighborhood because he was the only person who had a battery operated transistor radio. His neighbors gathered around him for news and information about the power outage. I shook my head in disbelief as this man extolled the virtues of his radio as if it was a revolutionary new invention.

This power emergency was not unlike other disasters where people flock to stores for water, flashlight batteries, food and other basic supplies. Unfortunately, with each disaster we hear stories of dishonest vendors charging outrageous fees for necessities. People just don't prepare enough.

Though not essential to life, electricity is one of the things we would miss the most during and after a disaster or regional emergency. This is evidenced by the thousands of generators sold before an impending hurricane. A safer option is to use sunlight to create power during these stressful periods. You don't need solar for back up power, but you do need solar if you want to quietly recharge your backup battery bank on a daily basis. Please read part one "Safer Lighting with Solar" for an important discussion on generators that most people haven't considered. Photovoltaics (PV) panels don't pollute and they are quiet so they don't draw unwanted attention.

Lighting is probably the most important use for backup power. We need light to see what we are cooking and eating, to go to the bathroom, read, and take care of medical needs. The problem with flashlight batteries is that they run down quickly. Candles and other flame sources are dangerous and should not be used. The lighting article also suggests ways that we can use light to keep our families safer during emergencies so that an inconvenience does not turn into a disaster.

In addition to lighting, a reliable power supply is needed during power outages for communications. On-board batteries won't last long in radios, TV's, CB's, cell phones, walkie-talkies, shortwave radios and VHF radios. Other needs for power include; cooling, heating, refrigeration, water pumping, laptop computers, and even entertainment.

This last August the media reported that 3000 people in France died in one week due to a heat wave. Most solar systems are too small to handle air conditioning, but small backup battery systems can provide power for fans, and small evaporative coolers, providing comfort during heat waves. The suggestions in part three of this series Heating, Cooling and Refrigeration may help you avoid a similar tragedy.

A safe and renewable source of emergency power is important to have during emergencies, but the most common way to store that energy is lead-acid batteries, and by their nature they aren't safe. There are many books and articles about safe use of batteries. We suggest you study up on this "weakest link" of a backup power system.

Lead-acid "wet" or "flooded" batteries need frequent maintenance and care and there are other types of batteries that are less trouble. Gel-cell batteries do not require checking the fluid levels regularly. There are other batteries that act like a gel-cells, but store more power. They are sealed lead-acid batteries like the Optima or Concorde brands. These batteries can operate on their side or even upside down because they won't leak or spill when accidentally tipped over. While all storage batteries create explosive gasses when charging, these batteries "fume" less and are typically used in Wheelchairs and interior locations. They are a good choice for a home-made portable backup system or a commercial one similar to the XPower Portable Household Inverter. These sealed batteries are more expensive and they still can create a dangerous explosion if the terminals are shorted out.

Most solar systems use the typical 6 VDC golf-cart battery because of their ruggedness and lower cost. Smaller systems in Recreational Vehicles (RV's) often use 12 VDC "Deep Cycle" batteries. Typical automotive batteries will be unsatisfactory in all but the most dire of emergencies.


Most battery manufacturers have safety information and maintenance tips on their web site but I like Trojan's Battery Maintenance information pages because they give important information in a straightforward manner. The key to achieving optimum performance and long life is a solid battery maintenance program similar to the simple procedures outlined on these pages.

I wanted to include the Trojan battery maintenance information in this article, but I couldn't list everything and I felt it important that all of the information be read. It outlines the equipment needed, inspection of batteries, specific gravity testing, open-circuit voltage testing, watering, cleaning, storage, charging, equalizing and discharging information.

A 6-24 hour chart is shown in the Trojan info so you can periodically test the true condition (with a digital voltmeter) of your batteries. Though less accurate, we find it useful to use a simple one-hour chart for a quick test. RV'rs typically use this chart an hour after sunset on a daily basis. Any readings done during charging, or before the hour waiting period will result in false, higher readings. Until you have it memorized, I suggest you print off this chart and laminate it to keep it readily available.

One Hour Battery Condition Chart

Specific Gravity  

Voltmeter Reading  

State of Charge
















Safety First, Second and Third

In any back-up system the batteries take the most effort to maintain and they are the most likely part of a system to fail. If you follow the suggestions given by Trojan, you will have batteries that give you optimum performance with a longer than normal life expectancy. Remember to properly vent your battery storage compartment and follow all safety recommendations. Wear safety goggles and other protective gear when servicing batteries. Keep a box of baking soda nearby. Extreme cold and heat, as well as storing them in a discharged state, will reduce the life of your batteries. Always have a high respect for batteries when around them because they can be very harmful if not handled properly.


When charging solar batteries, a controller should be installed between the solar panels and the battery bank to prevent the batteries from being overcharged. Choose a controller with a digital voltage meter read-out so you can constantly be aware of the charge state of your batteries. Controllers need to be set for either lead-acid or gel-cell type because both require different cut off voltages. There are many types of controllers available. With small systems it is not critical which brand you get, but with larger systems you will want to do your homework.

Fuses, Breakers & Disconnects

All battery banks and circuits should have the proper fuses, breakers and disconnects installed to protect from shorting out wires or the battery itself. Wires can melt and cause a fire when too much current flows through, and all batteries can explode, spewing dangerous acid.

Other Chargers

If you are using a 110 VAC charger to keep your battery bank full of power, please use a charger that has a three-way charge. A three-way unit charges bulk (2-10+amps per hour), trickle (1-2 amps) and float (off to 1 amp). Most auto store chargers will not charge your batteries properly because they do not have the float cycle that shuts completely off when the batteries are full. Batteries left charging, even at a trickle, can boil away, ruining the battery. Most converters that come standard in RV's are bad for batteries because people forget they are constantly charging when the RV is plugged into 110 VAC "shore power". Our most popular 110 VAC three-way charger is the TrueCharge line. Some high-end inverters do double duty as they have three-way chargers built in to their circuits. A good three-way charger will noticeably lengthen the life of your batteries.


Inverters convert the 12 VDC from your battery bank to 110 VAC so you can run regular appliances. There are a wide selection of inverters on the market and technology has made virtually all of them more reliable and less expensive. The type of appliances you can operate depends on the size of inverter and battery bank capacity. We suggest that you never let your batteries get below 50% discharge and that you regularly only see a 20-30% discharge before you re-charge your batteries.

New Solar Products

There are several new products that can be valuable in an emergency, or just to make life a little easier along the way. One item I found at an RV show a few months ago was the PowerDock that is a portable mini power generating station capable of storing 9.2 amp/hrs of 12 volt electrical energy. The PowerDock has a heavy duty fifteen watt solar panel that charges a built-in dry-cell battery that allows you to operate your laptop, stereo, TV, cell phone, fan, light, etc. around the clock. It also allows you to charge your low-voltage equipment without using your auto battery. This rugged power station folds compact for portability, has two automotive cigarette lighter receptacles, two standard connectors, a built-in charge controller, power meter and a canvas jacket designed to hold accessories and your laptop. 

Another new product that is great for emergency power is a "solar panel in a tube" made by ICP. These extremely flexible solar panels come in three sizes and roll up in a small tube. They are lightweight and can be tucked in a small space for camping, boating, or packing with your "mobility" emergency evacuation bag. We have just received two sizes that roll up to about 3 inches in diameter, a 5 watt and 10 watt. They both come with electrical connectors, hook-up wire, a carrying strap and case.

Another new product I found in the local home center store was a solar candle. For years I have used the small solar landscaping lights with the small LED light in them that don't have wires. The same thing is now available that will sit on a table. A few of these on your patio charging up will be a great renewable light source for your kitchen if the power ever fails.

I expect LED lights to be more and more popular as the price comes down. This amazing bulb doesn't ever need replacing because it will last for thousands of hours, and they use very little electricity. Light bulbs with various numbers of LED mini bulbs in them approach the light output of regular bulbs, but they cost an arm and a leg. I also look forward to fiber optics to bring free light into our houses in the future.

With a little thought and preparation, you can solve many of your electrical needs safely in the event of an extended power outage. The do-it-yourselfer might want to make their own portable solar power supply, or put a 12 volt motor in a small swamp cooler to solve those electrical needs. We are lucky to be living in these times, independent living is a little easier for us than our grandparents.

Michael Little is the Manager of Vegas Trailer Supply in Las Vegas, Nevada. He has been involved with the solar energy industry for 20 years. He can be reached at: michael@vegastrailer.com.  More information on many of the products mentioned in this article can be found at http://vegastrailer.com.

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