Rechargeable batteries for Solar Panels

You have built your new solar powered system and they are providing power for your home.  But what happens when you leave the house, turning off your lights and appliances?  Where does all that fresh clean newly produced solar energy go now that your household demand has dropped to nearly zero? The answer is batteries.

A battery is a device that stores electrical energy.  Batteries are made up of positive and negative terminal material, separated by an electrolytic medium (something that allows the flow of electrons from one terminal to the other). They are different types of batteries and consequently uses for these batteries.

A Solar Energy System generates power during the day as the sun shines on the solar panels.  Typically this provides 5 hours of full strength sun power.  This generated power is usually more than what is required by the home user.  The excess power is stored in reserve for use at night when the solar panels cannot produce energy. 

Batteries are used to store the solar generated energy during the day, and then provide the energy to the home at night.    Without the batteries, your home would not be able to benefit from the massive energy of the sun generated power. There are many types of batteries.  Wet, Gel or Dry.

The best example of wet or gel type batteries are the automotive batteries we use in our cars.  Car batteries are designed for quick discharge followed by long slow recharge.

Marine or Deep Cycle batteries are a special purpose battery designed to provide a constant current for long periods.  Automotive batteries are designed to produce a high current for a brief period to start the motor.hese are the recommended type to use in a solar system but the size will depend on your needs. So the use to which the batteries are put will dictate how much solar power it takes to recharge them which will in turn dictate the solar panel to be attached to these batteries.

NiCad batteries are made from Nichol-Cadium and are a dry rechargeable type battery.  NiCad are used in many electronic devices but do not have the capacity required for a home solar energy system.

Lithium Ion batteries are the newest and most powerful variety of rechargeable battery.  Li Ion batteries have a storage capacity greater than Lead-Acid batteries, and have the same constant current delivery properties as the deep cycle batteries.

Li Ion batteries would be the ideal choice for home solar energy systems, however at this time, they are 3 to 4 times the cost of the available lead-acid deep cycle batteries.

After all solar power can be used to recharge many types of solar power batteries from the consumer level AA batteries all the way up to 48 V batteries. Some of those batteries are designed for only a few hours usage and others are designed for years of usage. Whether you get a single battery or have many batteries in a bank and whether the battery will be located inside or on the exterior also play into which of these solar power batteries you purchase.

Solar Power Batteries for Off Grid Uses

If you are interested in an off grid system you will want to have a large array of solar panels producing 12 V or 24 V power to charge your solar power batteries. And inverter then converts the power from DC to AC. There are lots of solar power batteries available to you but it is important to note that these are not car batteries or normal consumer type batteries because those batteries are designed for different applications other than solar power. For larger solar applications where you are powering your entire home rather than a single device you would want to get flooded lead acid batteries or modern lithium batteries for deep cycle performance.

AA Rechargeable batteries

The American National Safety Institute (ANSI) standardized the double A size of battery in 1947. At the time, household electronics were an emerging field. ANSI stepped in to standardize things and the end result is that today, you don’t have to comb the earth to find the right battery for your camera, or remote. AA batteries can be found in cameras, compact disc players, mp3 players, video game devices, GPS systems, etc. These batteries evolved from Primary batteries which were not rechargeable to the LSD batteries that are rechargeable. The rechargeable batteries have the same components as the primary batteries. They comprise of a positive electrode, a negative electrode, a separator and electrolytes (chemical solution). But, unlike primary batteries they can be easily recharged and used again anytime you want. This include NiMH batteries and NiCd batteries.

An effective use of these batteries in Solar lights. Solar lights use rechargeable batteries that are powered through a small solar panel fitted into the solar light. It is charged through out the day to provide power all night long. They can be charged for more than 1000 times and used again. However, in the initial stages, using these batteries can be a little difficult as their power drains out without any alarm or sign. Thus, you always need spare batteries which can help you continue with your work while the other set of batteries get charged.

Multicolored Solar Lights

However, the newly manufactured NiMH rechargeable batteries have the same life as the primary batteries and can be charged as efficiently as the basic rechargeable battery systems. These LSD batteries can outlast the normal alkaline batteries. The LSD batteries are available in AA, AAA, C, D and also 9 volt sizes. Among them, the C, D and 9 volt batteries that are not very easily available. However most Solar Lights just need Standard AA 1.2v battery.

Solar Panels & Batteries – Planning Your System Requirements

All components in your solar energy/electrical system are related to each other. The way you’re supposed to determine that initial battery and solar panel “requirement” so you can plan around anything making sense is to add up the power requirements (watts) of the things you’re going to run during a day. Your goal is to find out, in watts, how much electricity you need. Then figure the number of hours of sun your area gets during that day, etc., taking into consideration seasonal use. Theoretically you can put together a system that gives you that kind of power.

Interestingly enough, most people that do this with a home plan in mind often end up thinking they need way more than they really do. It’s much easier with a small simple solar system. It’s a confusing task but important; a necessity in fact. Just think about those things you’d like to have working. It requires specifics. What thing? How long per day? How many watts per hour? How many things at the same time? A little thought in this area is better than the wild guess method. Pay particular attention to the higher watt consuming devices you might use.

Just to play around. Let’s say you know you want to run a 95 watt portable computer for 3 hours a day. That’s 95 watts x 3 hours = 285 watts on computer usage. If you had a 50 watt panel pumping in 50 watts an hour (hope for bright sun) you’d still be providing only about half or less of what you’d need for that period of time. If your battery is big enough to withstand the short fall, you could hope your sun lasts for enough hours when you’re done with your computer to make up for it before you need it again. Or, you need more panels. Solar panels can charge the battery at the same time you’re drawing energy from it.

Sometimes how big you can go is determined not by solar panel size or battery capacity but by affordability and space and you just have to deal with it by limiting or spacing your use.

Solar Charge Controllers

The solar electrical charge controller controls the incoming charge to the battery. More complex/sophisticated charge controllers do even more. Your system cannot function without one. Any battery being charged, even with a small solar panel, can be over charged and destroyed given enough time without a charge controller.

The only time you may not need a charge controller is when using a 1-5 watt panel as a trickle charger. The intention of a trickle charger is to replace normal energy loss in a battery that occurs from just sitting. The general rule is that if a trickle charge panel puts out 2 watts or less per 50 battery amp hours you don’t need a charge controller. But, when in doubt, use one. Small ones are inexpensive.

Choosing a Solar 12v Charge Controller

Charge controllers come in all sorts of sizes as determined by number of amps with a variety of features as mentioned above and more. Since they’re sold by the number of amps and solar panels are sold by watts and the charge controller needs to be able to handle the watts put out by the solar panel, it’s helpful to repeat the equation, amps x volts = watts, but not always the most accurate method here.

A 4.5 amp charge controller is considered “small”. 4.5 amps x 12 volts (battery) = 54 watts according to the math. Putting math aside however, the most accurate thing to do is just read the amp rating off the solar panel specs.  It will be listed there. It’s an alternate measurement to watts. Other influences affect the amps put out by a solar panel that may change the real amp outcome.  Comparing amps to amps is better.

The Solar Battery Charger or Panel

A solar battery charger is a charger that uses the sun’s power to produce electricity which is measured in watts There are a variety of uses for this type of charge.

Low Wattage

A low wattage charger ( generally 4 watts or under) are all small and designed to maintain batteries that do not have a load being put on them while being charged. The output of these low wattage devices is so small that they are not designed to recharge drained batteries. This type of is designed for maintenance of power sports and marine starting batteries. These devices might have stands, some are mountable, and some are panels that plug into car cigarette lighters.

A Solar Panel Connected to an Electric Fence

Mid-Range Products

A mid-range series is approximately double the wattage of the previous category. In these you could have panels, mounting stands or cigarette lighter adapters. This type of solar panel, which is typically 5 to 10 watt, is recommended for usage in such applications as industrial gate openers, electrical fence chargers and smaller industrial equipment

Upper-Range Products

A solar charger of 11 W and up begins to have real capabilities for marine and industrial use and are often used for charging RVs and boating applications. Once the solar battery charger output of 11 W it up is reached then serious work can be done for recharging. For example solar panels range from 20 watts to more than 300 W. The panels can also be wired together either in series or parallel for many different applications.

Another specialized application is for RV and marine multi-battery charging and there are multiple output panels ranging from 62 watt to  around 130 watts in this category.While a it can be simply put on the dashboard of a car and plugged into a cigarette lighter, most chargers need accessories to fully achieve their usefulness.

Solar Panels on a RV

A solar panel can also be used in off grid applications and for almost any consumer device you can imagine. For example laptop computer, for those times when you are off grid but still need to recharge your laptop’s batteries. And the RV and marine applications are perfect examples of obtaining power from the sun’s rays when electrical connections are not available.

An easy way of thinking about this battery charger is to envision them as alternatives to plugging a charger into a wall outlet. Solar Panels create their own electricity rather than taking electricity from the grid. So you can be using the grid for most electrical applications while still using the free power of the sun to recharge many devices. So it can be either an adjunct to or a replacement for the electrical power from your wall socket depending upon what you want to achieve.