Battery backup systems can be a great option for people looking for insurance against power outages. Add solar panels into the mix to recharge your batteries and you could have the prescription to cure those power outage blues. Before you purchase a battery backup system to cure your ills, however, it is vitally important that you have an accurate diagnosis of the problem you want to solve.
In many ways solar power and battery backup represent a reliable form of protection against the unforeseen power outage. A battery backup system operates in much the same way as an uninterrupted power supply for your home computer. The electrical equipment and appliances on your backup won’t even flicker. You wouldn’t even have to reset your alarm clock. This instantaneous switching means that for some equipment, battery backup can be superior to a generator based system, which must start and warm up before switching on. Even with the best natural gas generator, you would still be in the dark for a short time if an outage occurred.
Sounds great right? There are drawbacks, however. Battery banks are expensive and they can only store a finite amount of energy. This means that in order to power large loads, such as air conditioning and older, non-energy efficient lighting and appliances, you will be making a significant investment in batteries. Your batteries will sit in their special enclosures topped off and ready for the lights to go out. After 7-10 years, even if they are never used, even the best batteries will need to be replaced. Hopefully, there will be a “magic bullet” storage technology that comes along to present an affordable replacement option, but if not, you will be making another investment in batteries, which could be $2-3000 for a basic system and much higher for whole house systems. This could be a bitter pill to swallow if no major outage occurred during that time frame.
The trick to making battery backup systems work starts with planning. Where will you put the equipment? An interior space in a garage is usually best and if it’s near your existing electrical panel, that’s even better because you may need to reroute some circuits. Think about the things that you really need to energize during an emergency and how long you want to use them each day. Next, think about how many days you want to have these items powered up even if it was raining outside and you aren’t getting much recharge from your solar panels. The more accurate you are with this process, the more satisfied you will be with your system because you will be less likely to experience your batteries going dead prematurely.
Now you can expect to get some recharge from your solar panels even on cloudy days, but if your batteries get into a state of deep discharge, you could find yourself in a situation where you can no longer meet the demands placed on the system by your loads AND recharge the battery bank to 100%. At this point, your only choice would be to hope the power comes back on, reduce the “load” on the system by turning things off, or introduce another charging source. A secondary charging source can be an attractive option and can increase the performance of your system while reducing its overall cost.
This option is called a “Hybrid System” and usually involves the integration of some sort of generator. Having a generator as part of your backup system may allow you to reduce the overall size of the battery bank and solar array while actually increasing reliability. With a hybrid system, when your batteries get low you can simply start the generator and run it until the batteries charge. Some systems and generators can even make this process automatic. There are several key benefits to this configuration. The obvious benefit is that since you have multiple sources, you have more latitude over what you can power during an outage. Suddenly, that window unit you are thinking about becomes possible. Secondly, you may be able to purchase a smaller generator than you otherwise would have installed because the battery system will be able to provide supplemental power to supply the surge current needed to start certain motors. Additionally, you will able to operate your generator at or near full load conditions which will make the most of your available fuel since a generator uses virtually the same amount of fuel whether it is powering loads at capacity or simply running full speed just to charge your cell phone.
So, what are your next steps? First, make up your “wish list” of the necessities you can’t live without during an emergency. Next, make sure you do everything you can to upgrade these items to the most efficient ones possible. It makes no sense to spend thousands extra on batteries to power a 15 year old refrigerator when you could invest in a modern unit that is 10 times more efficient, and you can enjoy the new one every day!Once you have an idea of how you want the system to perform and what you wish to energize, it will be relatively easy for your solar energy consultant to quote a system for you. Without a solid foundation to design from, however, the size and cost of the system is anyone’s guess and you run the risk of your system being too small, which means you run the risk of the system not performing, or too large, which means you spent more than you needed to.
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