Lithium Ion Battery vs Lead Acid Battery
Lithium Ion Battery vs Lead Acid Battery
Lead acid battery
The lead acid battery, compared to the lithium ion battery we use today, is environmental friendly. The battery is composed of a Lead-dioxide cathode, a sponge metallic Lead anode and a sulphuric acid solution electrolyte. Although with improper disposal this can be harmful to the environment. This battery provides high current within a short amount of time and maintains a large power to weight ration which is why it can be used to power cars. It also doesn’t cost a lot to make it. It is one of the most low cost and simple batteries to make.
It is a heavy and bulky battery making it less practical for compact use. It is also dangerous because there is a risk of overheating due to charging, which makes it not suitable for fast charging. The battery has a low energy to weight ratio meaning its energy capacity is low.
Lithium ion battery
The lithium ion battery is one of the most commonly used batteries today. It is used in smart phones because of its high energy density. It can provide energy for a long period of time. One of the most common problems with batteries is their discharge over time. Their battery capacity gets lower through time. Another advantage of the lithium ion battery though is that it has a low rate of discharge. Because of this, the capacity of the lithium ion battery doesn’t quickly deteriorate. This battery can also be operated with low maintenance. They do not need maintenance to ensure efficient performance.
One of the disadvantages of lithium ion batteries is its requirement for protection. These batteries need to be protected from being charged and discharged too much. Another one of the disadvantages of this battery is the ageing. Lithium ion batteries suffer ageing because its age depends on the charging and discharging cycles the battery undergoes. In addition to this, lithium ion batteries are expensive. Lithium ion batteries are “40% more costly to manufacture than Nickel cadmium cells (Poole)”.
How are batteries connected?
How are batteries connected?
In a golf cart that we saw, there were 6 batteries inside that was powering a 4kW motor. The total voltage of the battery pack was 48V. When we opened the seat, it was an unusual battery inside–8V in series.
So when we place them in series the batteries’ voltage add up:
Learn about how to series and or parallel batteries in our Solar workshop event this coming Dec 2-3. Details are in our facebook event page
Photo shows scenery in Baguio and batteries from an EZGO golf cart in Clark Freeport zone.
Achilles heel of solar
Achilles heel of solar
For all of solar’s strengths, it has one main weakness. You can’t use it at night.
Bambanti, harvest time, and solar irradiation
Bambanti, harvest time, and solar irradiation
The future of energy…today
Bambanti, harvest time, and solar irradiation
Isabela is the 2nd largest province in the Philippines, after Palawan. It is also the top producer of corn and among the top producers of rice for the country. Last January 23 to 28, 2017, the province of Isabela celebrated the Bambanti festival. The word Bambanti when translated in their dialect means scarecrow in English. The scarecrow is used to frighten away birds, pests and other insects or animals that can do damage to the produce of the land. In the end, it is meant to ensure that farmlands in Isabela have a good harvest in the coming year.
While harvest times are generally good times, “Magtanim ay di biro” literally expresses the sentiments of our farmers before harvest time. Aside from dealing with pests and unpredictable weather brought about by supertyphoons and El Nino, there’s the problem of irrigation, pesticides and the hard, manual labor out in the sun from sunrise to sundown.
While you need at least a hectare of land, 10,000 sq.m., to get economies of scale for rice and corn, a solar power system currently just needs 7sq.m. of area to get 1000 watts of energy. 1000 watts is already a good amount of power because it can already power a 1hp aircon.
On any given sunny day in the Philippines, we can “harvest” about 1000 Watts per square meter of land area. Just imagine a 1m x 1m square plot in your garden or open space. That small space receives 1000 watts of radiant energy from the sun at noontime on a cloudless day. The catch is that solar panel technology, with all its advancements in the past 20 years, can only convert 15-22% of that energy to electricity. That means only 150 to 220Watts can be converted to actual electricity in a 1sq.m. area of space from a radiant energy source of 1000Watts.
Although some solar panel makers claim 30% efficency, those are mostly on the laboratory scale. When manufactured in larger numbers the actual efficiency will decrease. The solar panels with the highest efficiency on a commercial scale belong to Sunpower of the USA. Most China-made solar panels now have efficiencies of between 15-19%, but they are improving every year.
Compared to growing rice or corn however, a solar panel’s produce does not rot, requires no pesticides or running water. All it needs is the right orientation and direct sunlight and it will harvest energy for you at least for the next 25 years.
To learn more about solar panels, solar panel efficiency, how to choose the right solar panels and its correct sizing for your requirements, attend our upcoming seminar in Cauayan City, Isabela, this coming April 8, 2017.
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5 Visual Checks you can do before you buy a solar panel
To make sure you get your money’s worth, it is important that you buy Tier 1 solar panels. If you plan to buy unbranded solar panels from local distributors to save on cost, make sure you do these 5 visual inspections. While these will not guarantee that your solar panels will run the distance, it will at least increase your chances of getting a good buy.
Two (2) of these visual checks have to do with solar cells. Solar cells are the building blocks of solar panels. These are the 125mm x 125mm square cells that are put together to produce different types of solar panels of different power capabilities. The more solar cells, the more power a solar panel can produce. All Tier 1 solar panel manufacturers can manufacture and produce their own solar cells. So they can control the quality of their solar modules.
An estimated 90% of solar panel manufacturers however, resort to buying solar cells from third party manufacturers and then piece together and assemble the solar cells to make a solar module and solar panel. Because these solar cells come from different manufacturers, there is no certainty about its quality.
Here are the 5 visual checks:
1) Alignment of solar cells and its tabbing wire. The tabbing wire is the connection of the solar cells to each other. Solar cells are connected through by soldering the tabbing wires of adjacent solar cells. If this process is not automated, there is a big chance of misalignment. When tabbing wires are mis-aligned, there will be uneven current flow. This uneven current flow could lead to malfunction and a phenomenon known as hot spots.
2) Broken or chipped solar cells. The best solar cells are classified as Grade A. They can produce more than 90% of their rated output and have little or no micro-cracks. There are some who say that Grade B is also acceptable but Grade C is unacceptable and can lead to short term degredation. So broken or chipped cells are a sign of a lower grade solar cell which should be avoided whenever possible. For more information about the grading of solar cells, see:
3) Scratches. This is a sticky issue since solar panels are prone to scratches during handling. Small scratches have no effect on the performance of the solar panel in the beginning. However, if the scratch is big enough, it could lead to earlier than expected degredation. So if you can check the panels, get a clean and flawless one without scratches.
4) Fading serial numbers. Serial numbers are the identifying numbers we use to claim for a defective solar panel. If the serial number is faded or un-readable from the beginning, there is definitely something doubtful about the manufacturer. When we made a claim for a defective solar panel late last year in 2017, the first thing the manufacturer asked was the serial number.
5) Particles inside the solar panel. We have not encountered this but there a chance that insects or other small particles can get inside solar panel between the glass and the solar cell. If this happens it is not a good indicator for the manufacturer. The region between the glass and the solar cell should be a complete vacuum, with absolutely nothing in between.
If you want to learn more about solar panels and solar energy systems in general, we will be going to Davao on March 8. For tickets and registration, see link below:
Watch out also for an upcoming seminar in Isabela on April 8.
The image above was taken from a store window in Cubao. The image below with a broken solar cell was taken from Sinovoltaics, good source of information about solar for Asia.
The one thing you need to check with solar panels
So what do we really need to check in the solar panel? Is it the appearance? Is it the size or the power that is important? How do we make sure that we get the right quality of solar panels and prevent the above from happening?
Solar panels are the most important part of the solar power system. They’re the ones that get energy from the sun and put it in batteries for storage or deliver energy directly to your house through DC to AC inverters. In terms of cost, the solar panels comprise 40%-50% of the total system cost. Although solar entails a huge one-time, big-time investment, you can get back your investment in as little as 5 years. For smaller systems it will take 6-7 years.
Solar panels are getting cheaper every year. When I first experimented with solar panels in 2006, I opted for a German made panel (supposedly) from a company in Greenhills and paid close to 20k for it. The solar panel power output was a whopping 20W at that time. Now we can get solar panels at half the price for more than 10X the power. And they are slowly becoming a commodity. One businessman I know even remarked that we have to get this solar business before it becomes like plywood.
Most solar panels now in the Philippines can be divided into just 2 categories–those that are >250Watts and those 100Watts and below. Solar panels rated 100W and below are almost a commodity. But those rated 250W and above are not. When we started our company in 2013, the industry standard was 250Watt for medium sized installations from 1kW to 20kW. Now, 3 years later, there standard is 265Watts to 285Watts. They have gone from P12k-P17k per panel to the current rate of P7.5k-P9k per panel. This lowering price doesn’t mean we can buy any solar panel that’s 250W and above. There’s still a lot more to consider.
Price is also important but it’s not the most important thing to check. If we could check one and only one thing about the solar panel, it would not be the specs, efficiency, appearance, power or features. Because all of the features are useless unless the supplier or installer honors the warranty. If there is one and only one thing you should check for in the solar panel, it is the supplier’s ability to honor the 10-25 year warranty on the solar panels.
To learn more about solar panels and the systems that can be built around it, attend our upcoming seminar this coming February 25. Visit and like our facebook page for more details:
or call 738-1136/775-1027/0997-2880892/0917-5307337 for further inquiries.
Your ultimate guide for solar panel and battery matching
For solar panels between 10W and 150W, here’s your ultimate guide on what battery to use for charging. During sunny days, we can expect an equivalent charging time of between 4-6 hours irregardless of solar panel size. Even though there are 12 hours of daytime, the equivalent energy harvest for solar in the Philippines is 4-6 hours.
Here’s how to use the table. If you need to charge a 10Ah battery, you would need at least a 20W solar panel to fully charge it. The “solar time” it will take for it to get fully charged is 4.4h. If you have a 50W solar panel, a 20Ah battery can be fully charged within 3.5h. Our recommendation is to use only the solar panels covered in the yellow area for each battery capacity between 10Ah to 75Ah.
The reverse is also true, if you have a 10Ah battery, don’t bother using a 10W solar panel to save on cost because the battery will never be fully charged, even on sunny days. There isn’t 8.8 hours of solar time to do that.
Note that we assumed lead acid batteries here where only 50% of its rated capacity is charged and discharged over its lifetime. Getting more than 50% will severely degrade and reduce the lifetime of a lead-acid battery. So the usable energy for a 20Ah battery is effectively only 10Ah. You can have 10h of run time for a 1A load. A 10W bulb for example can run the whole night on a 20Ah fully charged battery.
Connecting 2 solar panels in parallel will double the charging current and thus reduce the time it takes to fully charge a battery. When you connect 2 100W panels for example, you double the charging current to about 10A, reducing the time it takes to fully charge a 75Ah battery by half. So instead of 6.6 solar hours, it will only take 3.3 solar hours for the 75Ah battery to get fully charged.
Solar panel power point
Two of the most important specifications in a solar panel are the open circuit voltage (VOC) and the maximum power. A solar panel’s VOC can be checked by using a multi-tester or a voltmeter. The two test probes of the multi-tester are connected to the two terminals of the solar panel and the voltage will be displayed. If there is no voltage or there is no display, there must be something wrong with the solar panel. Most solar panels from 20W to 100W have an open circuit voltage VOC of between 18-22V. Then the 60cell panels that are from 250W to 265W have a VOC of 36-38V. The bigger 300W+ panels have a VOC of around 45V.
It is important also to note that VOC is the voltage when the solar panel has no load. In such case, the current flowing through it is zero. So it’s perfectly safe to measure the voltage of a solar panel under the heat of the sun. Just make sure the terminals are not shorted together or they can form a path through you and you can get electrocuted. The voltage is effectively potential energy. VOC is the maximum voltage that the solar panel can give.
Once the solar panel is loaded, for example it gets connected to a charge controller or grid-tie inverter, the voltage drops by 10-20% and it begins to deliver its maximum current. When the solar panel delivers it maximum voltage and its maximum current, that’s when it’s operating at its maximum power point. The job of ensuring that the solar panel operates in this region falls on the grid-tie inverter and some MPPT charge controllers. Even a few tenths of a volt (0.5V) difference from this maximum power point can cause the power of the solar panel to drop by 50%.
For more information on solar panels and how it can yield its maximum power, you can attend any of our seminars this coming November.Click the link button below for the details of seminar.
Common appliance that can run by off grid system
This chart shows what our Off Grid System can run depending on the appliance usage. In general, it takes almost the same energy to run a ref 12-24 hours just as it is to run an aircon 2-4 hours. To run an aircon off the grid for 4-8 hours, it would cost P180k to P320k. The biggest variable here is the size and number of batteries. As you increase the number of batteries, the number of solar panels have to increase as well.
Each 250Watt panel can put in 8A of current during the house of 11am-1pm when the sun is out and there are no clouds. If we sum all the current that can go into a battery for one whole cloudless, sunny day, it would amount to 32Ah. Assuming 50% depth of discharge, a 250W panel can easily charge a 100Ah battery.
Another good combination would be 2x250W panels and 2 x 120Ah batteries. These can power most households’ lighting requirements with 2-3 bedrooms + kitchen and garage.
To power an airconditioner at night, you would need at least 1 200Ah battery to power a 1hp aircon for 1 hour. To power it for four hours you would need 4x200Ah batteries and 3x250W panels.
Wiring and other considerations for solar installation
Fig. 1. Wire cross-sectional area in mm2
Before connecting the solar panel to the grid-tie inverter or the charge controller, the solar developer must decide what size of wire to use. These are the steps involved:
1) Get the power requirement (PW) of the device, solar panel, or load.
2) Get the current (A) requirement of the electricity path by dividing the power requirement PW by the voltage V that will run through it.
A = PW / V
If you already know the current passing through the wire in Amperes (A), go directly to step#3 below.
3) AWG#8 has 8mm2 of wire area and so can pass 32A of current. Start from there. For every mm2 of wire, less than 4A should run through it. If your current is less than 32A, go down the next wire category in Fig. 1 (AWG#10, 5.5×4=22A). If your current is more than 32A, go up the next wire category. Do this until your current is as close to the wire rating ampere capability
If your wire passed the condition in item#3, your wire is sized according to standards.
Let’s take an example. A 250Watt solar panel passes a maximum 8.5A. AWG#14 is too close and AWG#10 is a bit oversized. AWG#12 is just right and can pass 14A (3.5X4).
AWG#10 and AWG#12 are the most common wire sizes used for solar panel installations and household wiring for lights and typical appliances.
Wiring is just one of the many considerations involved in solar power system installations. If you want to learn more, attend our solar seminar held every end of the month.
For more details, visit our facebook page or check this page out.
Depth of Discharge vs. Cycle Life
One of the more important considerations in the maintenance and life of a battery is its depth of discharge (DOD). How a battery is discharged affects its lifetime. In more technical terms, discharging the battery by 50% will result in more life cycles than discharging it by 80%. The figure below shows the projected life cycle based on DOD’s of 100%, 50% and 30% taken from www.pveducation.org.
The graph above is theoretical and you should ask your battery manufacturer for the actual DOD vs. cycle life of their battery. For Motolite, we asked their technical support engineer and this is what they gave:
30% DOD 750 cycles
50% DOD 450 cycles
The voltage setting to determine the appropriate DOD depends on the discharge rate. For 50% DOD, at C/10, the cut-off voltage is about 12V. But at the higher rate of C/5, the cut-off is 11.5V. So for a 100Ah battery, if the discharge rate is 20A, the cut-off is 11.5V. But for a discharge rate of 10A the cut-off is 12V.
Faith and Reason
Walk of Faith, San Mateo, Rizal
In the movie, “The Bucket List”, starring Jack Nicholson and Morgan Freeman, the characters of Edward and Carter are having a discussion on an airplane ride home about their beliefs in God. Both of them are terminally ill from cancer. Edward is a self-made billionaire who’s agnostic while Carter is a regular, hard-working mechanic with an old-fashioned belief in God. The conversation goes something like this:
Carter: The stars…It’s really one of God’s good ones.
Edward: So you think some being of some sort did all these?
Carter: You don’t?
Edward: You mean if I look up in the sky and promise this or that, the big…will make this all go away? No.
Carter: Then 95% of the people are wrong.
Edward: If life has taught me any of this, it’s that 95% of the people are always wrong.
Carter: What do you believe in?
Edward: We live, we die, and the wheels on the bus go round and round…Is there something you know that I don’t?
Carter: No. I just have faith.
I share this conversation in the movie because I’ve also had this conversation in my mind as a scientist/engineer and a believer in the Big Bang theory. It’s really difficult to get faith into your head. If you look at all the stars, which are a million lights years away, it’s very difficult to think that there’s someone out there orchestrating all that goes on down here. The nearest neighboring star to our sun, the Proxima Centuari, is 4.37 light years away. Light travels at the speed of 186,000 miles per hour. Even at the speed of light, it would take that light source, 4.37 years to reach us. Just imagining the magnitude of the universe makes it really hard to believe that there was a God that could look after us—small infinitesimal beings in the galaxy of bigger-than-life stars.
Then what if the reason for our belief is because we’re afraid to face our fears? If we remove the fear then all our belief can go away. While being confined in a hospital for 2 weeks after an unsuccessful endoscopy operation, I had this fear of death and suddenly not being able to see my kids grow up. So right then and there, in the darkness of the recovery room after my operation, I had to invent a God, even if I didn’t have one. And I desperately called out to Him to make sure that I had some extended time. But that’s just me. I know of strong personalities who do not fear the great beyond and have lived meaningful lives. And so they have no need to believe in God even to the point of death.
In another scene in “The Bucket List”, while on top of the ancient Egyptian pyramids, Carter explains to Edward that Egyptians believed that they would be asked by guards two questions at the gates of heaven. Their answers to these two questions would determine whether they were admitted or not. These two questions were: 1) Have you found joy in your life? 2) Has your life brought joy to others?
Those questions are quite tough to answer irregardless of what religion (or non-religion) we adhere to. But many life coaches attest to the prospect of death as a defining moment of our lives. When faced with death, we will be forced to answer questions similar to those two just mentioned. Did our life matter? Did we find meaning and purpose in our lives? How did we give meaning and purpose to others? Even Steve Jobs in his famous graduation speech at Stanford said that in the face of death, you’re forced to focus only on what is important.
Towards the end of the movie, “The Bucket List,” Carter writes a moving letter to Edward and mentions that “our lives are streams flowing into the same river towards whatever heaven lies in the mist beyond the falls.” Then he advises Edward to find the joy in his life, close his eyes, and let the waters take him home. I don’t want to give the storyline away but the movie is a good alternative to “The Greatest Story Ever Told” or “The Passion” of Christ.
There were many other questions posed in that movie. I don’t know if it was inspired by the TV program Jeopardy but the other question that the characters in the movie tried to get their heads to was the measure of a life. Morgan Freeman’s character, Carter, at the beginning of the movie believes that “you measure yourself by the people that measure themselves by you.” There’s at least a grain of truth to what he said. When people measure themselves against you, then you must have done something right to merit that.
One of the reasons for my renewed faith in the Catholic Church was a chance pilgrimage in October 2011 with the then Bishop of Imus, Cavite, the current Archbishop of Manila and now Cardinal Chito Tagle. Hearing him speak, learning about his life and works, having a chance to walk with him in the Holy Land changed most of what I knew and believed in about the Catholic faith. From that pilgrimage my image of God literally changed from one that was distant and all-knowing to One that had a more human, unassuming face, One with a humble demeanor willing to walk with us and go our ways. The image of God Cardinal Chito gave was one I was not accustomed to–a kinder, gentler face that was a far cry from the stern and serious figure looking over our shoulder regularly, checking if we went to confession or not. In that pilgrimage, he was the closest image to Christ that I could see in a lifetime. He absolutely had none of the trappings of power, prestige or glory. And everywhere we went in that pilgrimage he was carrying a small bible. It was as if God’s word and his were one. And everytime he opened the bible to read something, we listened to his stories and how they changed him or some other person’s lives. His homilies during that pilgrimage were living proof that Christ and His words was relevant 2000 years ago as they are today.
Then think about it. No other government, corporation or political dynasty has achieved as much. Whatever you think of the Catholic Church today, one thing cannot be denied. Christ’s organization, His words, and His works, with his original ragtag team of 12 followers, has withstood the test of time. No other leader, even with an army of thousands or a financial capital of a billion $, has duplicated that feat. No other movement has inspired 1.2-2.2 Billion followers. (Facebook is close but it still has to withstand the test of time). Christ’s story, with all His stories with real people we could identify with, still remains one of the greatest and most inspiring stories ever told.
The Jewish Rabbi Yeckiel Eckstein wrote in one of his blogs that there are two miracles in the Exodus story. The first miracle is the parting of the Red Sea. The second miracle, he adds, is when the walls of the river did not fall on the Isrealites as they crossed the river. I do think it’s a very appropriate imagery for the times we live in today. It almost feels like walls of water will come crashing in on us, making it even harder to keep our heads above water. But we keep plugging, keep moving, letting the rivers of life take us to where the eternal sea dwells—having faith that when all these things come to pass, we’ll be taken to a heaven that’s just right for us.
How do I know? Just like the character Carter, I don’t know everything. But just like him and the 95%, all we have is faith.
Road Less Traveled
It’s fascinating how some words live beyond the lifetime of the author. Robert Frost, who wrote the poem “The Road Not Taken”, lived until 1963 but his poem published in 1920 lives on. I would never have expected that those lines would come back to me almost 30 years after.
In the beginning of the poem, the main character is faced with a fork in the road and he says that sadly, he cannot traverse both. Then in the middle of the story, the main character chooses the one less worn out. Before the story ends, he looks at the road he did not take and wonders if he made the right choice. In the end, he reasons that the road he took has made the difference in his life.
“TWO roads diverged in a yellow wood, And sorry I could not travel both…”
That is so true with our careers. Very seldom do we see someone extremely good at both science/engineering and the arts. It has to be one or the other. During my generation, maybe even up to now, the most popular choice for a college course would be something related to business. I chose Computer engineering with Physics. It was not a very popular course and so our batch started out with 40 but there were only 16 of us who went on to graduate with a Physics/CE degree
“Then took the other, as just as fair, And having perhaps the better claim, Because it was grassy and wanted wear;”
No job choice is easy. There is always a trade-off. Very few really get to practice their course. Doctors becomes nurses. Engineers become programmers. Lawyers become bankers. And usually the biggest trade-off at the beginning of a new graduate’s career is between doing what you love and making enough money.
When I graduated from college in 1991, I had the choice of going into the more lucrative software side of engineering against the less lucrative hardware side. Because I wanted to build and develop things through research and development (R&D), I chose the latter. My first job was a design engineer for a Taiwanese company in Cavite where I spent 5 hours travelling by bus, jeep, and tricycle to and from Rosario, Cavite and Quezon City. On rainy days the travel time was even longer. On those rainy days, as I battled with our passengers to get to the back of the jeep, I wondered if I had made the right choice.
“Yet knowing how way leads on to way, I doubted if I should ever come back.”
Indeed one road leads to another and in the year 2000-2004 I scraped and clawed my way from being a design engineer to a manager of over 50 engineers in a Japanese semiconductor company called ROHM LSI Development company. It was hard and fun to go inside the electronic devices that power our cellphones and computers.
Then in 2013, I faced another fork in the road. It was either to continue as an employee or strike it out on my own.
Again the choice wasn’t easy and again there were trade-offs. With my wife’s approval, I chose to strike it out on my own.
The nice thing about the poem is that it makes no imperative to take the road less traveled. In fact, the main character doubts whether the road he took is really the one less traveled. But since he is too far into the woods, he knows that he cannot come back and undo the choice he made.
Very few can predict what can happen 5 or 10 years down the road. But I hope to say after 10 years that:“I took the one less traveled by, And that has made all the difference.”
Riverbanks, Marikina City, Jan 2015
Some phenomena or things need to happen before a rainbow can be seen in the sky. Some part of the sky has to be experiencing rainfall. Then the sun reflects its light on the water droplets resulting from that particular rainfall. As the light from the sun passes through the water droplets, it is broken down into its component parts, particularly the colors red, orange, yellow, green, indigo, blue and violet (or ROYGIBV). Then the light gets reflected twice and refracted once at an angle of at least 40 degrees. For one to see a rainbow, the sun has to be behind the observer and the water droplets in front.
There’s an air of mystery to the rainbow. Some ancient peoples believe it was a passageway from life to death. Irish folklore says that there is a pot of gold at the end of the rainbow. Kermit the Frog says that at the end of the rainbow is where our dreams come true. It may have been the inspiration for the proverbial “silver lining” beneath every cloud. For Christians, the ninth chapter of Genesis mentions the “bow” in the clouds as a symbol of God’s covenant or promise to not let the great flood happen again.
Whatever we believe about rainbows, I have to say that whoever engineered the creation of rainbows knows what He’s doing.