DAY 22: CHARGE CONTROLLERS

 

Day 22 of #100daysofsolarnuggets

What is a charge controller?

     A charge controller is a device that controls the charging of the batteries in the battery bank. It is placed between the battery and the solar panel. The main purpose of a charge controller is to prevent the batteries from getting overcharged. It regulates the current flowing in and out of the batter,this is done to ensure your batteries last long and more importantly this is done for users safety.Charge controllers come in different shapes sizes and color.

Features of a charge controller

Below are some of the feature of a charge controller, some charge controllers have more features than the other.

.1) Prevents the battery from overcharging.

This is the main function of a charge controller, batteries are very sensitive components, so care must be taken not to overcharge them. The charge controller regulates the voltage and current coming into the battery.

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.2) Blocking reverse current.

At night when the solar panels are not producing anything, the battery has a higher voltage than the panels because of this higher voltage, current from the battery would try to find its way back to the solar panels and if this is allowed,it could damage our solar panels. The charge controller prevents current from flowing from the battery to the solar panel. (newer models of solar panels also come with  a way of blocking reverse current in built as a precaution)

.3) To prevent deep discharging.

Discharging your battery below 50%  significantly reduces the lifespan of your batteries, the charge controller monitors battery usage and alerts  you, when your battery is about to be discharged  below the recommended level.

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.4) data logging

Some charge controllers record the values from your solar systems such as the maximum power generated from your solar panels, current , voltage, battery levels and the likes, this is done on a daily basis and it stores this data in the memory of the charge  controller .This helps you to monitor your solar system and detect any fault that may arise early enough. It also enables you to have a record and keep track of the performance of your system.

There are two types of charge controllers

.1) PWM (Pulse Width Modulation)

.2) MPPT (Maximum Power Point Tracking)

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DAY 21: SOLAR FARMS,THE QUEST FOR CLEAN ENERGY.

#100DaysofSolarnuggets

    There is an interesting trend playing out in the global scene that I believe more people should be aware of. A lot of countries in the drive to create clean energy are investing massively in solar farms (photovoltaic power stations)

What are solar farms?

     A Solar farm is a large expanse of land that has a lot of solar panels installed together to generate electricity at a very large scale which is now fed back into the grid.Solar farms are also known as Photovolatic power stations. The capacities of this solar farms vary. There are solar farms that generate between 10 to 50 MW and there are those that generate as much as 500 MW and above.   #100DaysofSolarnuggets

   Currently the largest solar plant in the world is Longyangxia Dam Solar park in China, this has the capacity to generate a whooping 850MW. There are a lot of solar farms In the world we have kamuthi solar power project in India that has the capacity of 648MW,Solar star 1 and Solar star 2 both  located in the United states and each of them having a capacity of 597MW each.

   There are still many more solar farms in the world, as at writing this article the largest solar power plant is Longyangxia dam solar park but there is no guarantee that in next one or two years it would still be largest, lots of countries in their quest to cut down their carbon emissions and reduce their over dependence on fossil fuels are undertaking some ambitious solar farms project. As I write this article the Quaid-e-Azam Solar Power Park (QASP) in Pakistan is on a quest to becoming the largest solar farm in the world with an estimated capacity of up to 1000MW once completed, it aims to generate as much as 1.271bn KWh of energy annually. There are a lot more similar project being conceived by others.    #100DaysofSolarnuggets

 To give you an idea of how large this kind of project is the Longyangxia dam solar park in China has the capacity to power approximately 200,000 homes.

What are the limitations?

.1) Cost

Solar farms are cost intensive, costing quite a lot of money to create. To successfully build a solar farm you would need a lot of materials Solar panels, Inverters, transmission lines and a lot of other things.

A lot of solar panels are needed sometimes to generate about 100MW you would need somewhere between 300,000 to 400,000 panels. The largest solar farm has close to 4million panels, Inverters are needed to convert the DC current to AC current.

.2) Regular cleaning.

 Solar panels must be cleaned regularly especially during dusty periods, dirt accumulating on the solar panels significantly reduce the efficiency of the panels.This is a lot of work because a lot of panels are involved.

.3) Sun tracking vs fixed panels.

To efficiently utilize the intensity of the sun Solar panels should be facing the sun always, Solar trackers when installed alongside our solar panels help it track the movement of the sun at all times (from sun rise to sun set), a lot of solar farms have fixed solar panels placed at the optimum position to get solar light. Installing solar trackers comes at additional costs.

.4) Night.

As we all know solar energy can only be generated in the presence of sunlight, which means in the Night time nothing would be generated.

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To be continued.

DAY 20: CARE OF YOUR BATTERIES

DAY 20 of #100DaysofSolarNuggets  

                                                  

CARE OF YOUR BATTERIES

Your batteries are an integral part of your solar installation, taking proper care of them would ensure they last very long for you. Today I want to discuss some tips that would help you a great deal preserve your battery life.

.1) Do not discharge your batteries below 50%.

    This is very important, discharging your batteries below 50% significantly reduces the lifespan of your batteries, Please note even if you are using lithium ion batteries that can discharged as low as 10% if you so desire, doing so also reduces the battery life even though the effect may not be as severe as that of lead acid batteries. If you maintain a 50% discharge limit, you would get the maximum life cycle from your batteries. #100daysofsolarnuggets

.2) Do not overcharge your batteries as well.

Yes we have charge controllers (we would discuss about charge controllers in subsequent articles), and charge controllers control the charging of the batteries making sure they are not over charged. But I still think it is important I mention it.

.3) Do not overload your batteries

Avoid overloading the batteries, this can weaken the cells of the battery, if this happens your battery may not last for you, batteries are very sensitive to over loading. To avoid overloading, ensure you do a proper stock of the appliances that would be used with your battery bank and get the appropriate battery bank to match it.

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.4) Minimize the rate of discharge

Even when your battery is not in use, it discharges very slowly as a result of chemical reaction that occurs in the battery. To minimize the rate of discharge in your batteries, do not place your batteries directly on the earth surface (floor), make use of a wooden board or a nonmetallic battery rack.

.5) Always use Batteries with the same ratings

Avoid using dis-similar batteries in your battery bank, this is very important and cannot be over emphasized.

What happens if you make use of dis-similar batteries, let’s have 2 batteries

Battery A = a higher AmpHour(AH) 12V 200ah and

Battery B = a lower AmpHour(AH) 12v 150AH

What would happen Is this, the battery with 150AH would discharge faster than the 200AH battery, very soon  the 150AH battery would get faulty, leaving only the 200AH to do the work that was meant for both batteries, what do you think would happen next .The 200AH battery also gets faulty and you would lose a lot of good money.

Picture it this way

Two adult horses are need to successfully pull a cart from point A to point B, but instead of using 2 adult horses, you make use of one adult horse and a baby horse, well the baby horse would get tired in a very quickly leaving just the single adult horse to do the job of two adult horse very soon he too would get tired and they would not get to their destination.

To avoid loss of batteries and money always use batteries with similar ratings.#100daysofsolarnuggets

.6) Regular top up (flooded lead acid batteries)

If you are making use of flooded lead acid batteries, regular maintenance is required. Ensure you top up regularly making use of distilled water only. Place your batteries in a well ventilated area.

.7) Regular cleaning and check up

Clean the terminals of the battery  (especially for flooded  lead acid batteries, check for cracks along the sides of the battery, that way you can detect a potential acid spill before it happens.

Hazard

Warning, If you notice any liquid spill from your batteries on the floor, do not let it touch your body. Acid spills from batteries are corrosive. You can make use of baking soda to neutralize it or you use a lot of water.

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DAY 19:BATTERIES,SOME MORE THINGS YOU NEED TO KNOW (pt 2)

 Day 19 of #100daysofsolarnuggets

Hello everyone,
So today we are going to continue from where we stopped yesterday.

FACTORS YOU SHOULD CONSIDER WHEN CHOOSING BATTERIES FOR YOUR SOLAR INSTALLATION

.3) Capacity
Batteries store electricity, they do not generate electricity, so how much electricity they can store is a very important factor you must look out for. Your current electrical usage should form the basis for the capacity of the battery bank you need.

Generally you add up two or more batteries in series or in parallel, most times you do a combination of both series and parallel connections of your batteries to get a battery bank. This is because more often than not, a single battery may not be sufficient for your energy needs.

Batteries are usually rated in this format “12V  150AH”.
(AH = ampHours), 150AH means that ideally this battery can give you a current of 15amps for 10 hours (15amp x 10hours = 150AmpHours) or a current of 30amps for 5 hours (30amps x 5hours = 150AH).Note the amount of current you draw from your battery depends on the appliances you have on it. If your devices/appliances require a lot of power, your battery drains faster and if your appliances do not require much power, it does not drain as fast. Therefore the more appliances you have the higher the capacity of batteries you would need.

Please do note it is very important to use similar batteries in your solar installation.(would explain more about this when I discuss about battery sizing)








.4) Cycle life
This is simply how many times the battery can be discharge and charged before it fails or it can no longer be charged to its full capacity. A cycle occurs when a battery has discharged (electrical energy has been used) and then it is charged to its full capacity. Typical lead acid batteries if properly used have life cycles in the range of 300 – 500cycles, Lithium batteries can go a lot higher as much as 1500cycles.

A very critical factor that affects the Life cycle of any battery is the Depth of Discharge (DOD).

The recommended Depth of discharge value for a deep cycle battery is 50%, Please note it is very important not to discharge your deep cycle batteries below 50%, discharging your batteries below 50% considerable reduces its overall lifespan.

Also ensure your batteries are charged fully after discharge, this would ensure your batteries last long.





Tomorrow we would be looking at How to maintain your batteries

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Day 19 of #100daysofsolarnuggets

Day 18: BATTERIES,SOME MORE THINGS YOU NEED TO KNOW

Day 18 of #100daysofsolarnuggets

Hello every one

We have spent the past few days looking at batteries, Deep cycle batteries (lead acid), where we have the flooded, gel and the AGM. We also looked at Lithium batteries and the Nickel based batteries.

Today we are going to be looking at how batteries work and also some factors to consider when choosing a battery for your power bank.I may go a bit technical here so I ask that you all bear with me,i promise to make it as simple and clear as possible.

To answer this question how do batteries work, we need to know what a battery is made up of,

A battery has 3 main components

.1) the positive electrode

.2) the negative electrode

.3) the electrolyte

The electrodes are the terminals of the battery, made up of conducting materials (metals), this are called anode and the cathode.

Now  most of the time  the Anode is the negative electrode and the Cathode is the positive electrode, although this is not always the case with all kinds of batteries, take a look at your battery, besides the electrodes ,you would see inscribed on the battery the negative sign beside one electrode and the positive sign beside another.

I also want to quickly mention, rechargeable batteries like the ones we use for Solar Installation have their polarities reversed during charging ,what this means is that the positive side(electrode) during discharging becomes the negative side(electrode) during charging and the negative side(during) during discharging becomes the positive side  during charging.

The terminals (anode and cathode) are separated by a fluid which is called the electrolyte

Electrolyte

This is basically a fluid that allows electrical charges to flow through it, a medium or a channel through which electric charges flow between the cathode and the anode.

Once a battery is connected to a load, reactions begin to occur at the electrodes, this reactions causes electrical charges to flow between the electrodes and as electrical charges flow between the electrodes electrical energy is generated,this energy then lights up the bulb or what ever appliance you have connected to it that lights up the bulb.                       

                                                                 

WHAT ARE THE FACTORS TO CONSIDER WHEN CHOOSING BATTERIES FOR YOUR SOLAR INSTALLATION?

There are a lot of factors to consider when choosing a battery,

We would look at two today then look at the rest tomorrow

.1) Efficiency                                                                                                                 

I believe that efficiency should be the number one determining factor for choosing a battery and not cost. When setting up a battery bank for your solar systems, I advise that you get the best battery your money can buy. You may get a good bargain on a cheaper battery, but in the long run you would soon discover that you would have to replace the batteries a lot more often,which would cost you.

,2)Cost

Cost should be the second factor to consider when trying to get batteries for your Solar system.The different types of batteries have their different costs,usually the most efficient batteries are the most expensive.That said we should always try to strike a comfortable balance within the cost of the battery we want to get and it's efficiency and that is very important.

To be continued…..

Day 18 of #100daysofsolarnugget

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DAY 17: BATTERIES: (LITHIUM-ION AND NICKEL BASED)

Day 17 of #100daysofsolarnuggets

Good day everyone,
   The past two days we have talked about batteries, Lead acid batteries in particular. Lead Acid Batteries are the more popular choice of batteries when it comes to solar installation, but there exist other kinds of batteries that are also used.

    I would discuss about those batteries, I believe this knowledge would would help inform our choice of batteries when setting up a solar energy system.

Lithium-ion batteries

     This type of batteries are not as popular as the Lead acid batteries, but they are very good batteries, Lithium batteries are an improvement in energy storage techniques, when compared to the deep cycle batteries that has been around for a long time Lithium batteries are a relatively new technology.

    Unique features.

       Lithium-ion batteries have an amazing near 100% efficiency, this simply means if it says it would give out 10kwh, It would give 10kwh, unlike the deep cycle batteries that have about 50% efficiency.(to preserve the life span of the lead acid batteries, you are advised not to discharge it below 50%,while lithium batteries can be discharged till it's near empty).

     Lithium-ion batteries have a longer lifespan, can perform at least 3 times more cycles(charging and discharging) than a lead acid battery.

      Lithium-ion batteries have a much higher cost compared to lead acid batteries in the ratio of 2:1

     Lastly it is worthy of note that lithium batteries are a much cleaner technology and this feature is in line with our goal for clean green energy.

Nickel based batteries

      We have both Nickel cadmium and Nickel iron batteries.

      They have almost the same properties as Lead Acid batteries, efficiency ratings of about 50% and also require occasional toppings.They release gases so they should be located in a well ventilated area.

      Nickel cadmium is not ideally suited for daily use as it would die out very quickly.

    Tomorrow we would be discussing factors to consider when choosing a battery bank for our system,

Day 17 of #100daysofsolar nuggets

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