Some batteries require maintenance. If they are not cared for, their chemical properties can be affected. This leads to premature failure. Other batteries do not require maintenance, but may not be suitable for solar applications. Before buying batteries, you have to consider each model’s characteristics and see if it fits your intended use.

Let’s consider 3 types of rechargeable batteries we commonly see in the market: Lead-Acid batteries, Alkaline Batteries and Sealed Gel-Cell Batteries.

There are pros and cons to each type of battery, so let’s look deeper.

Flooded Lead-Acid Battery

This type of battery was used since homeowners began to install solar panels on their roofs. They have the longest proven track record. (Thus you can consider them to be pretty reliable.)

In fact, most off-grid solar power systems use this type of battery. This is because they have the longest lifespan and are the cheapest among different types of batteries (in terms of cost per amp-hour).

However these batteries require regular maintenance. You have to water it regularly, equalize the charge and clean the terminals frequently.

Flooded lead-acid batteries commonly used for photovoltaic systems include 6V golf cart batteries, 6V L-16 batteries and 2V industrial cells.

Absorbed Glass Mat Sealed Lead Acid Battery (AGM)

Sealed lead acid batteries gained popularity as their price came down. Unlike flooded lead-acid batteries, they do not require as much maintenance. They are ideal for grid-tied PV systems that use rechargeable batteries as backup.

AGMs are completely sealed. Therefore there is no danger of spilling and they do not need frequent watering or charge equalizing. It is designed such that no corrosive fumes are emitted. Its electrolyte also does not stratify.

During storage (or transportation), an AGM’s self-discharge rate is less than 2%. Thus they are popular with any setups that do not require frequent battery use.

AGMs are highly resistant to any forms of vibration, thus they are ideally suited for mobile solar power systems installed on vehicles and boats.

These batteries used to be very expensive. As such, they were only installed on commercial systems where maintenance was impractical or near impossible.

Today, AGMs are only slightly more expensive than other battery types. Thus many homeowners are willing to sacrifice some money for the sake of convenience.

Gelled Electrolyte Sealed Lead Acid

Gelled lead acid batteries are quite similar to AGMs in terms of its advantages. There is one important distinction, though. Gelled electrolyte is very viscous. Therefore recombination of gases generated while charging takes place at a very slow pace.

This means you can only charge them slowly…much slower than AGMs and flooded lead acid cells. If they are charged quickly, gas bubbles form on the metal plates. This reduces electrolyte contact. As a result, the battery’s capacity is temporarily limited until the bubbles find its way to the top of the electrolyte.

For off-grid solar power systems, this characteristic is not helpful. During the day when solar panels generate electricity, you have to store as much power as possible. If the charging rate is low, a lot of power is wasted. Therefore such batteries are more suited for grid-tied systems where the majority of electrical current is channeled back to the grid.

Deep Cycle or Shallow Cycle?

The battery is an important component of your solar power system. Thus its performance and longevity is of utmost importance.

For solar applications deep cycle batteries are used. Compared to shallow cycle batteries, deep cycle batteries can be repeatedly discharged to 80% of its depth of discharge (DOD) and can be recharged from this state without damage.

Commonly batteries used in automotives and lighting belongs to the shallow cycle type. These are not suitable for a PV system. The lead plates in these batteries are thin and have a large surface area. Even though it can provide a high current in a short time, these batteries cannot be discharged deeply without damage. At least deep discharge cycles can shorten their lifespan quickly.

Deep cycle batteries have thicker lead plates and less surface area in contact with the electrolyte. As such, these batteries produce less current than a shallow cycle battery. However deep cycle batteries can sustain its current over a long period of time (unlike shallow cycle batteries), which is ideal for solar power applications.

Deep cycling puts a toll on your battery’s lifespan. This applies to deep cycle batteries too. Therefore if you want batteries to last longer, use deep cycle batteries and shallow cycle them (as much as possible).

Storing Your Batteries

Place your battery bank indoor where it is warm. Batteries work best when they are about 25 degree Celsius. If batteries are cold, chemical reactions slow down. Therefore less current flows out of the batteries. You may have experienced trouble starting your car in cold weather. But when the battery warms up, its performance improves dramatically.

On the other hand, batteries cannot be exposed to high temperatures too. At 43 degree Celsius, rechargeable batteries can be damaged and their lifespan shortened drastically.

When buying batteries, you must remember there is no perfect system. Energy is lost to heat (or other forms) as it flows from one component to another. When electricity flows into your batteries, some of it is lost.

Therefore you have to factor this into your decision and get more batteries to compensate for power loss. As a rule of thumb, you should have 10 to 15% more power storage (batteries) than what you need.

Maintenance

Batteries need maintenance. Make sure you keep the electrolyte at full level, as much as possible. If not, you must at least keep it above the minimum level. Otherwise the plates may get exposed to air. When refilling, use distilled water.

Water is lost as gassing occurs. This is a process of splitting water molecules into hydrogen and oxygen. It occurs during charging when the chemical reaction cannot keep up with the energy input.

In flooded lead acid cells, some gassing is useful. It introduce movements in the electrolyte and prevents stratification. Denser acid tends to stay at the bottom and they are stirred as gassing occurs.

As a result of gassing, an acid mist is formed and this is highly corrosive. Therefore you have to check the metallic connectors for signs of corrosion or damage from time to time. Clean the top of your batteries regularly with baking soda and water. Baking soda, being alkaline, will neutralize the acid on the battery and connector surface.

Other than refilling and wiping your batteries, you must also equalize them every 2 to 3 months. (This should be done in a well-ventilated place.) During this process, increased gassing occurs and this cause the water level to drop.

To equalize your battery, simply overcharge it under a controlled voltage for a period of time. While doing so, your battery must be closely monitored. You must keep measuring the specific gravity values of the electrolyte. It increases as you equalize the battery. When there is no change in specific gravity reading for 30 minutes, the equalization process is completed.

Used Or New?

When buying batteries, it is tempting to spend less money by purchasing pre-owned stock. This is understandable. After all batteries are not cheap. And expensive batteries don’t mean they are good or suitable.

The issue with used batteries is you won’t immediately know how they were used and maintained. If you send them for load testing, you can find out their remaining lifespan. Otherwise they can turn out to be the most expensive batteries in the market.

When you find out facts and use simple logic to your decision making process, you will find batteries that can last for ages without failing.

Continue Reading:

1. Sizing Your Solar Energy Panels – Part 3
2. Solar Energy Storage – Where To Keep Excess Energy Generated By Your Solar Heaters Or Photovoltaic (PV) Panels
3. How Do You Know If Solar Panels Are Suitable For Your Property?

It takes a little skill and practice to harvest components from pre-owned or broken solar panels. Yet it is not so difficult that you cannot manage it with basic DIY skills.

You have to free the photovoltaic cells from the base it’s mounted on. After you have done this, check the solar cells for loose connections, broken panels, condensation and damaged diodes. Common problems such as these can potentially cause your solar panels to break down shortly after installation.

If the joints between solar cells are broken or loose, you have to re-solder them. Malfunctioned diodes can be replaced with new ones from your local component store. And if you see broken photovoltaic cells, you will have to source for a similar component to replace it — this can be challenging. Yet you can still make do with the broken cell in case your efforts to replace the broken solar cell fail. There will be reduced power output as a result, but this is not a grave concern.

The array of solar cells is usually mounted on a piece of masonite or acrylic (substrate) board before it is placed into a new solar panel frame. You can discard this substrate after a few years if you intend to replace the solar cells with fresh, new ones.

Using pre-owned solar panels to build DIY solar panels has its pros and cons. The most obvious advantage is the price. Used solar panels can be very cheap and some kind contractors may even give them to you without asking for a single cent. You are also less worried about breaking expensive photovoltaic panels while building your project.

On the other hand, a used solar panel’s lifespan may be significantly shorter. Their power output will also be a little lower compared to when it was new. A loose connection or a fault may hide itself somewhere that escapes your attention. As you build your DIY solar panel, trouble may spring up from these areas. However this can be managed if you’re careful in checking for potential failures.

Overall, harvesting parts from a used solar panels proof to be the best money saving method to build DIY solar panels. The only downside is the additional effort you have to put in. Yet as DIY hobbyists, we tend to take joy in such labor.

Continue Reading:

1. How To Build A Personal DIY Solar Power System With Less Than $99
2. Step-By-Step Guide To Build A 12V Solar Panel
3. How To Find Used Solar Panels

A Heated Pool

There are 2 common methods to heat up your swimming pool using solar energy. You can use solar pool covers or you can use a solar water heater.

First let us look at what these are, then we’ll touch on the advantages and disadvantages of each system.

Solar pool covers are special pool covers that also absorb energy from the sun. They are dark colored and absorb heat better than other types of pool cover. Heat that is trapped in the material is passed to the water by conduction.

These products serve 2 purposes – to warm up your swimming pool and to prevent heat loss by evaporation.

Solar water heaters collect solar energy by using a solar collector. In order to warm your swimming pool water, you have to pump water through it.

The interior of a solar collector is black. This helps to absorb as much heat from the sun as possible. There is a layer of insulation lining the walls of the solar collector. There are also pipes that run through it, carrying cold water.

Inside a basic solar collector, heat is transferred directly to the water passing through it. Thus it also acts as a heat exchanger. Big solar water heaters use a separate heat exchanger in order to handle more capacity.

Pros and cons of using solar pool covers

Solar pool covers need neither installation nor maintenance. All you have to do is pull it out from its bag or roller and spread it across your swimming pool.

And as long as it covers most part of the pool, it’ll be able to do its job well. Some pools are kidney shaped, so you can simply float 1 or 2 rectangular (or square) shaped covers over its surface.

Solar pool covers, like ordinary covers, prevent water loss through evaporation. Thus it saves you the trouble of filling up your pool with water and chemical. And by keeping dirt and debris out, your cleaning time is also reduced.

Pool covers, however, can be dangerous. This is because if children (or even an adult) were to jump or fall into it, he can get wrapped in the cover. He may find it difficult to get out of the pool cover and might drown as a result.

Or if someone swims under the cover and tries to surface for air, he won’t be able to… until he reach the end of the pool.

As convenient as solar pool covers are, they eventually deteriorate and begin to fray. Fragments of plastic can get into the filter and choke it. It may even damage the filter medium.

Yet when you use caution and check the condition of your solar pool cover regularly, these events are unlikely to happen.

Pros and cons of using solar water heater

Solar water heaters for swimming pools take very little time to install. One hour is all it requires. It is also not a great hassle to fit solar water heaters to the pumps and controllers in the filtration system.

There are many different types of solar heaters, ranging from simple to complex. Therefore you can easily find one that fits your needs. They are also not expensive since they do not necessarily need to be glazed and workmanship does not affect its performance seriously.

Compared to solar pool covers, solar water heaters can heat up your pool better and there is more control. Thus you can enjoy warmer water (if that’s what you want) and you can always turn off its valve if it gets too warm for your liking.

Like solar pool covers, solar water heaters have their disadvantages.

With numerous constrictions within its design, your pool pump has to work harder to push water through solar water heaters. You’ll eventually end up with a higher energy bill.

Even with a solar heater, if you are not using your pool for some time, you still have to pull a cover over the water to prevent water and heat loss.

(A good addition to this is to plant bushes to divert or break up wind blowing over the pool.)

In order to help your pool pump run better, you have to choose a solar collector that does not have sharp bends in the piping. Also, ball valves are more efficient than gate valves. Therefore ask before buying.

If you haven’t bought your pool pump, you may also want to choose one that is smaller and has a higher efficiency. When using it, remember that you do not have to run it the whole day in order for it to clean effectively. Start with 8 hours, then increase or decrease the running time till you feel it’s filtering at its maximum efficiency.

Continue Reading:

1. Pool Solar Panels
2. What Are Solar Heaters, How They Work And What They Are Used For
3. 7 Different Ways of Using Solar Energy At Home and In Your Office