Everybody wants the best solar battery in Ghana.There are certain specifications you should use when evaluating your solar battery options, such as how long the solar battery will last or how much power it can provide. Below, learn about all of the criteria that you should use to compare your home energy storage options, as well as the different types of solar batteries.

LITHIUM VS AGM Ghana

freedom won lithium-ion battery installed in Accra,Ghana

How to compare your solar storage options

As you consider your solar-plus-storage options, you’ll come across a lot of complicated product specifications. The most important ones to use during your evaluation are the battery’s capacity & power ratings, depth of discharge (DoD), round-trip efficiency, warranty, and manufacturer.

Capacity & power

Capacity is the total amount of electricity that a solar battery can store, measured in kilowatt-hours (kWh). Most home solar batteries are designed to be “stackable,” which means that you can include multiple batteries with your solar-plus-storage system to get extra capacity.

While capacity tells you how big your battery is, it doesn’t tell you how much electricity a battery can provide at a given moment. To get the full picture, you also need to consider the battery’s power rating. In the context of solar batteries, a power rating is the amount of electricity that a battery can deliver at one time. It is measured in kilowatts (kW).

A battery with a high capacity and a low power rating would deliver a low amount of electricity (enough to run a few crucial appliances) for a long time. A battery with low capacity and a high power rating could run your entire home, but only for a few hours.

Depth of discharge (DoD)

lithium vs AGM ,DEPTH OF DISCHARGE GRAPH,GhanaMost solar batteries need to retain some charge at all times due to their chemical composition. If you use 100 percent of a battery’s charge, its useful life will be significantly shortened.

The depth of discharge (DoD) of a battery refers to the amount of a battery’s capacity that has been used. Most manufacturers will specify a maximum DoD for optimal performance. For example, if a 10 kWh battery has a DoD of 90 percent, you shouldn’t use more than 9 kWh of the battery before recharging it. Generally speaking, a higher DoD means you will be able to utilize more of your battery’s capacity.This has always been an issue in Ghana .Most people have erroneous impression that batteries need to be completely drained for batter performance.

Round-trip efficiency

A battery’s round-trip efficiency represents the amount of energy that can be used as a percentage of the amount of energy that it took to store it. For example, if you feed five kWh of electricity into your battery and can only get four kWh of useful electricity back, the battery has 80 percent round-trip efficiency (4 kWh / 5 kWh = 80%). Generally speaking, a higher round-trip efficiency means you will get more economic value out of your battery.

Battery life & warranty

For most uses of home energy storage, your battery will “cycle” (charge and drain) daily. The battery’s ability to hold a charge will gradually decrease the more you use it. In this way, solar batteries are like the battery in your cell phone – you charge your phone each night to use it during the day, and as your phone gets older you’ll start to notice that the battery isn’t holding as much of a charge as it did when it was new.

Your solar battery will have a warranty that guarantees a certain number of cycles and/or years of useful life. Because battery performance naturally degrades over time, most manufacturers will also guarantee that the battery keeps a certain amount of its capacity over the course of the warranty. Therefore, the simple answer to the question “how long will my solar battery last?” is that it depends on the brand of battery you buy and and how much capacity it will lose over time.

For example, a battery might be warrantied for 5,000 cycles or 10 years at 70 percent of its original capacity. This means that at the end of the warranty, the battery will have lost no more than 30 percent of its original ability to store energy.

Manufacturer

Many different types of organizations are developing and manufacturing solar battery products, from automotive companies to tech startups. While a major automotive company entering the energy storage market likely has a longer history of product manufacturing, they may not offer the most revolutionary technology. By contrast, a tech startup might have a brand-new high-performing technology, but less of a track record to prove the battery’s long-term functionality.

Whether you choose a battery manufactured by a cutting-edge startup or a manufacturer with a long history depends on your priorities. Evaluating the warranties associated with each product can give you additional guidance as you make your decision.

LITHIUM VS AGM, Ghana

Victron Energy AGM super cycle batteries installation in Accra

Automotive companies are jumping on the energy storage bandwagon

Home energy storage technology and electric vehicles are a lot alike: they both use advanced batteries to create more efficient, sustainable products that can reduce greenhouse gas emissions.

As electric vehicles become more popular, more companies are dedicating significant research and development funds to developing batteries, and they’re expanding into the energy storage business. Tesla is the first mainstream example (with their Powerwall battery), but Mercedes-Benz and BMW are also bringing standalone batteries to the market in 2017.

How long do solar batteries last?

There are two ways to answer this question and the first is to determine how long a solar battery can power your home. In many cases, a fully charged battery can run your home overnight when your solar panels are not producing energy. To make a more exact calculation, you’ll need to know a few variables, including how much energy your household consumes in a given day, what the capacity and power rating is for your solar battery and whether or not you are connected to the electric grid.

For the sake of a simple example, we’ll determine the size of a battery needed to provide an adequate solar plus storage solution with national average data from our research at Nocheski Solar. The average Ghana household will use roughly 15 kilowatt-hours (kWh) of energy per day and a typical solar battery can deliver some 5 kWh of capacity. Thus a very simple answer would be, if you purchased three solar batteries, you could run your home for an entire day with nothing but battery support.

In reality, the answer is more complicated than that. You will also be generating power with your solar panel system during the day which will offer strong power for some 6-7 hours of the day during peak sunlight hours. On the other end, most batteries cannot run at maximum capacity and generally peak at a 90% DoD (as explained above). As a result, your 5 kWh battery likely has a useful capacity of 4.5 kWh.

Ultimately, if you are pairing your battery with a solar PV array, one or two batteries can provide sufficient power during nighttime when your panels are not producing. However, without a renewable energy solution, you may need 3 batteries or more to power your entire home for 24 hours. Additionally, if you are installing home energy storage in order to disconnect from the electric grid, you should install a few days’ worth of backup power to account for days where you might have cloudy weather.

 

Solar battery lifespan

The general range for a solar battery’s useful lifespan is between 5 and 15 years. If you install a solar battery today, you will likely need to replace it at least once to match the 25 to 30 year lifespan of your PV system. However, just as the lifespan of solar panels has increased significantly in the past decade, it is expected that solar batteries will follow suit as the market for energy storage solutions grows.

Proper maintenance can also have a significant effect on your solar battery’s lifespan. Solar batteries are significantly impacted by temperature, so protecting your battery from freezing or sweltering temperatures can increase its useful life. When a PV battery drops below -1.1 ° C, it will require more voltage to reach maximum charge; when that same battery rises above the 32.22 ° C threshold, it will become overheated and require a reduction in charge. To solve this problem, many leading battery manufacturers, like Tesla, provide temperature moderation as a feature. However, if the battery that you buy does not, you will need to consider other solutions like earth-sheltered enclosures. Quality maintenance efforts can definitely impact how long your solar battery will last. Temperatures in Ghana range between 25-35 deg Celsius.

What are the best batteries for solar?

Batteries used in home energy storage typically are made with one of three chemical compositions: lead acid, lithium ion, and saltwater. In most cases, lithium ion batteries are the best option for a solar panel system, though other battery types can be more affordable. Order you Lithium batteries in Ghana here

  1. Lead acid

    Lead acid batteries are a tested technology that has been used in off-grid energy systems for decades. While they have a relatively short life and lower DoD than other battery types, they are also one of the least expensive options currently on the market in the home energy storage sector. For homeowners who want to go off the grid and need to install lots of energy storage, lead acid can be a good option.This is the most common solar battery type in Ghana.

  2. Lithium ion

    The majority of new home energy storage technologies, such as the , use some form of lithium ion chemical composition. Lithium ion batteries are lighter and more compact than lead acid batteries. They also have a higher DoD and longer lifespan when compared to lead acid batteries.  However, lithium ion batteries are more expensive than their lead acid counterparts.This is the least common solar battery type in Ghana

  3. Saltwater

    A newcomer in the home energy storage industry is the saltwater battery. Unlike other home energy storage options, saltwater batteries don’t contain heavy metals, relying instead on saltwater electrolytes. While batteries that use heavy metals, including lead acid and lithium ion batteries, need to be disposed of with special processes, a saltwater battery can be easily recycled. However, as a new technology, saltwater batteries are relatively untested, and the one company that makes solar batteries for home use (Aquion) filed for bankruptcy in 2017.This battery type is virtually non existent in Ghana.


Solar Power ,energy excitement in Nigeria.The market at Sabon Gari in Kano state, Nigeria, has 12,000 shops where you can buy everything from vegetables to visual arts. It’s so big they call it ‘Mini Africa’. Several kilometres of bustling passageways and roads, packed with shoppers and the shouts of traders calling attention to their bargains, makes for an exhilarating atmosphere …you simply can’t visit Nigeria and not go there!

Solar energy POWER excitement in Nigeria World recognition for huge Solar-Powered Market 8

© Alexander Kohler, Source Persistent Energy

However until recently there’s been something else in the atmosphere, too: quite a lot of smoke!

Noise and fumes

Grid electricity supply problems resulted in 72% of the shops which needed electricity deciding to generate their own power using petrol and diesel generators – a survey found. Apart from the pollution and the noise, the market regularly experienced destructive fires causing damage estimated in the millions of Naira.

Solar power, energy excitement in Nigeria World recognition for huge Solar-Powered Market

© Alexander Kohler, Source Persistent Energy

To address this and similar issues, The Federal Government of Nigeria, through the Rural Electrification Agency launched Energising Economies Initiative (EEI), to focus on building a reliable energy infrastructure at markets and other economic hubs – together with private developers.

Solar power energy excitement in Nigeria World recognition for huge Solar-Powered Market 5

His excellency the Vice President of Nigeria, Yemi Osinbajo accompanied by REA CEO/MD Damilola Ogunbiyi conducting inspection of one of the energy hubs at Sabon Gari.

 

His excellency the Vice President of Nigeria, Yemi Osinbajo accompanied by REA CEO/MD Damilola Ogunbiyi conducting inspection of one of the energy hubs at Sabon Gari.

Survey, design, install

The Nigerian based off-grid energy specialist Rensource – who aims to build West Africa’s largest portfolio of electricity micro-grid utilities using best-in-class technologies – were asked to carry out the installation.

Rensource recruited and trained 100 engineers, administrative staff, and craftsmen. Like so many countries, Nigeria has a large jobless population – new recruits were drawn from amongst Nigeria’s unemployed.

The first goal was to win the confidence of market stall holders that reliable power provision could be a reality – it was something no one had experienced before. A ‘needs’ survey provided the team with information essential to their system design …some shops needing only lighting; others had  air-conditioning and refrigeration units.

Solar power energy excitement in Nigeria World recognition for huge Solar-Powered Market 2 

How was it achieved

Working from survey results, a colossal 1.6MWh bank of Lithium-iron Phosphate batteries from hybrid battery manufacturer and technology partner BOS AG, based in Germany was selected as the power storage solution. The power installation was zoned into 160 10kWh systems – each providing power for between 60 and 80 shops.

Solar power energy excitement in Nigeria World recognition for huge Solar-Powered Market 3

800kVA of power is made available using 160 Victron MultiPlus inverter/chargers. These inverters have a peak power capability equal to double their continuous output – which ensures smooth power supply even as air conditioning units, for example, cycle on-and-off.  320 Blue solar MPPTs 150/70 units harvest the power from a 1.6MWp solar array, optimising the charge current to the Lithium iron battery bank.

Solar energy excitement in Nigeria World recognition for huge Solar-Powered Market 6

The system allows for future expansion – which is just as well because business is booming and demand for power is growing.

This clean electricity – made affordable by smart meters – brings only benefits it seems: Whereas the price of generator-produced electricity was around 1000 Naira per day, smart energy has brought that cost down to 116 Naira, typically.

International recognition

The success of this huge project has received deserved international recognition – Rensource won the Excellence in Climate Solutions award at the Transformational Business Awards ceremony (also known as ‘the Oscars of the renewables world’) which was held in June 2019, hosted by The International Finance Corporation (World Bank Group and Financial Times.

Since the completion of this project, four more markets now benefit from renewable electricity with a further fourteen scheduled. These developments are bringing welcome employment and training to enthusiastic young people who are really enjoying being involved with such a worthwhile scheme.

Rensource team after the inauguration ceremony! This project helped create many jobs for the youth of Nigeria.

Veeresh Anehosur of BOS AG says: The key to these mini grids and micro utility projects is that they need to be commercially attractive and sustainable in long-term. This is possible only if the technology works flawlessly over the years. ‘Low’ or ‘No’ system downtime and good system-level performance helps win customer confidence in the project – which decreases non-payment risk …a perfect scenario to recoup the initial investment. How do you ensure an efficient and cost-effective mini grid over time? One key element is to include lithium. Lithium has one of the least LCOE [Levelized Costs of Energy] compared to Lead acid. For projects where an initial low-capital investment is critical, a combination of Lead acid and Lithium can be used which gives a cost-effective high-performance solution.

Let’s have a look around the market, and hear how market traders are getting on with their new clean power:


How the Digital Inverter Compressor Has Transformed the Modern Fridge.For decades, Refrigerators or Fridges  had single-speed compressors that were always either off or on. A compressor is the engine that powers the refrigeration cycle, moving refrigerant through the inner and outer heat exchange pipes. With a single-speed compressor, when the temperature inside the fridge reaches above a certain temperature, the compressor suddenly switches on – a noise almost everyone is familiar with. The single-speed compressor operates at full power, producing enough cool air until the temperature has sufficiently decreased before abruptly shutting off.

Enter the digital inverter compressor (a compressor that can operate at variable speeds because it is operated with a digital inverter). Unlike the standard single-speed compressor, which is either off or operating at full speed (typically about 3,600rpm), the digital inverter compressor is almost always on, but can operate at different speeds – from 1,100 to 4,300rpm. This ensures high efficiency and consistent temperature inside the refrigerator. It also results in significant cost savings, a reduced carbon footprint, less noise and a longer lifespan for the compressor. The digital inverter compressor is one of the most important innovations in the history of Fridges and food preservation and Samsung has led the way.

Today, digital inverter compressors are the main technology used in Samsung’s signature appliances eg, air conditioners, washing machine & Fridges, including those that are part of the Chef Collection, the T9000, as well as food showcases and large-capacity premium Fridges. This has played no small role in Samsung’s ascent to become the world’s top refrigerator manufacturer.

In addition, Samsung has become a technical leader, as one of the world’s top manufacturers of this game-changing technology. Samsung produced more than 40% of the world’s digital inverter compressors in 2014 as other major manufacturers now use Samsung’s superior compressors in their Fridges.

Samsung really began its rise in this area in 1999 when the company pushed investment in BLDC (brushless direct current) inverter compressors. Since then, Samsung has continued to expand its investment in research and development, hiring a highly skilled team of researchers, which has enabled the company to remain on the cutting edge of technology. From 2000 to 2014, Samsung sold a total of 27.5 million BLDC inverter compressors, which are highly efficient and less noisy compared to a single-speed induction motor compressor. BLDC motors are also better in terms of reliability and longevity. The current Chef Collection refrigerator employs a fifth generation technology of BLDC inverter compressor.

The benefits are obvious. A fridge with a Samsung digital inverter compressor consumes up to 46.9% less energy than a single-speed induction motor compressor, and thus contributes far less in the way of greenhouse gases. Because the digital inverter compressor gradually speeds up and slows down, it does not have to work as hard to manage the temperature. This means that Fridges with digital inverter compressors suffer less wear and tear on components and are therefore far more durable than fridges with conventional compressors. This has allowed Samsung to offer a 10-year warranty on its digital inverter compressors.

The lack of abrupt starts and stops means no sudden, potentially startling disruptive noises interrupting your dinner. Digital inverter compressors are also far less noisy overall: up to 3 decibels quieter. And the consistent, uniform cooling that maintains the desired temperature means food lasts longer because changes in temperature can lead produce, meat, fish and dairy to spoil more quickly. It all means that consumers will save money on both their electric bills and food costs.

When Samsung sought input from its highly influential group of culinary experts, also known as the Club des Chefs, they emphasized that temperature uniformity is a crucial component of any fridge that may be used in a Michelin-starred kitchen. Chef Collection Fridges boast “Chef Mode,” which ensures that the temperature fluctuates no more than plus or minus 0.5 degrees celsius. The Chef Collection refrigerator is equipped with three evaporators and two compressors to control humidity. It is also made of stainless steel panels, which help to keep the temperature consistent.

These Digital Inverter technology based appliances are best used with solar power options for 2-5 bedroom homes from Nocheski


Interfacing for up to 25 charge controllers

Adding to Victron’s comprehensive range of Solar Charge Controllers, we can now announce new models with VE.Can connectivity. These currently include the SmartSolar MPPT 150/70 & 150/100 VE.Can with auto-select voltage for systems of 12, 24, 36 and 48 Volts.These new models are replacements for the BlueSolar MPPT 150/70 & 150/85 CAN-bus generation.The new VE.Can 150/70 and 150/100 models are now in stock and available for delivery. Further models will follow and are detailed later in this blog. Dealers can check availability and stock levels via E-Order.

Why VE.Can?

With the VE.Can interface up to 25 Charge Controllers can be daisy-chained and connected to a Color Control GX or other GX device. Each controller can be monitored individually, for example on a Color Control GX and on the VRM website.

VE.Direct and Bluetooth data communication are also features of these controllers.

To learn more about data communication such as VE.Can – see the PDF ‘Data communication with Victron Energy products’, in our Whitepapers section of the main website.

Comparison of VE.Can SmartSolar MPPT to the previous BlueSolar MPPT CAN-bus generation

  • Improved: each charger is displayed individually on a GX Device and on the VRM Portal; whereas with the previous models all units were operating synchronously and were seen as one; which made it impossible to see individual PV string performance.
  • Improved: supports ESS and control by Intelligent (canbus) batteries, just like today’s VE.Direct models; which was not possible with the previous generation. Note that this will require Venus OS v2.40, which is not yet released yet but is expected in October.
  • Synchronisation: the mechanism to operate synchronously is the same as before: equal device instances enables synchronised charging. Since they are all configured with Device instance 0 out of the box; they’ll automatically start synchronising as soon as you connect them together with the network cable.

Note: These new models cannot synchronise with the previous generation. They can of course still be used together in the same system; but will then operate autonomously.

Future developments & firmware

In addition to these new 150V, 70 & 100A models, there will also be a 150V, 85A plus 250V, 70A & 100A models. They are expected by the end of this year.

Furthermore some special and not commonly used features have not yet been released, but will come later as a firmware update. These are the virtual load output, street light, alternate TX/RX pin functions and the PAYG features.

Key product features & similarities

Key features are listed below, yet these new VE.Can SmartSolar MPPT is also very similar to the existing range of SmartSolar Chargers with a VE.Direct port; in that the hardware design is based on that reliable and proven range, they can be configured with the VictronConnect app and they support all the exact same charger settings and options.

  • Ultra-fast Maximum Power Point Tracking (MPPT)
  • Advanced Maximum Power Point Detection in case of partial shading condition
  • Outstanding conversion efficiency
  • Flexible charge algorithm
  • Extensive electronic protection
  • Bluetooth Smart built-in
  • Internal temperature sensor and optional Smart Battery Sense
  • VE.Can: the multiple controller solution
  • VE.Direct or VE.Can
  • Remote on-off
  • Programmable relay
  • Optional: SmartSolar pluggable LCD display

To read more about the features listed above, see the product page and PDF datasheet. The downloads section in that page includes all the usual certificates, product dimensions, photos, manuals and system schematics too.


EnGo – Smart Solar Street light pole is made by   EnGoPlanet ,the  sustainable solar lighting experts   recently launched a stylish new street light pole product which can even be retrofitted.The attachable design is of a solar cylinder module which can be quickly and easily mounted on any suitable pole for easy installation and disassembly.

Using 6 slim solar panels, with a solar cell efficiency of up to 21.2%, fixed to a hexagonal frame, ensures that half of them will face sun light at any time of the day.

The off-vertical cluster arrangement of the panels makes them less vulnerable to high-winds, less likely to accumulated dust and grime, and easier to clean.

The energy is harvested by a Victron SmartSolar MPPT 75-15. Bluetooth enabled, SmartSolar MPPTs include features which protect the battery from being too deeply drained, and have intelligent dynamic charge algorithms which work with the seasons to ensure the battery will at least periodically be returned to 100% charge.

EnGoPlanet use their own high-quality Lithium batteries, making the unit suitable for off-grid applications where night lighting is required. EnGo – Smart Solar Street light pole can also be used where a grid connection is present – in which case the units will run from their own batteries except where long-continued spells of poor weather require a power supplement to be drawn from the grid. This option is recommended for locations which are often cloudy, or shaded.

Alternatively, grid connected poles can be supplied without battery. Energy produced by the panels will be sent directly to the grid. Savings of up to 80% are possible.

EnGo – Smart Solar Street light pole  installations are also able to collect valuable environmental data which can be interrogated online. Other applications for the poles are for uses such as CCTV, sensors, wifi hotspots, and even phone charging points.

At Nocheski, we  look forward to installing  EnGo – Smart Solar Street light pole  soon

Justin Tyers


In the dark of night, students in a rural village in Ghana huddle around a kerosene lamp to complete their homework. Others shine flashlights to illuminate textbooks. The lack of electricity, nonetheless computers, dimmed the prospects of a bright future for students in the village of Kpantarigo. This was until Francis Abugbilla, a second-year doctoral student at the Henry M. Jackson School of International Studies at the University of Washington in Seattle, brought electricity to them in the form of solar power.

“The world is technologically-driven. I want to empower the children in my community by giving them a quality education,” he said. “I don’t want the children in my village [of Kpantarigo] to lag behind the world.”

Even though his village of over 1,500 had no electricity, computers, schools or clinics, he knew from his own experience that education is the impetus for change.

Making education matter
Born and raised in a small farming community, Abugbilla worked as a shepherd and began his formal education at 12. He was determined to excel. He walked nearly two hours a day to and from the elementary school in another village. The money his family scraped together paid for the kerosene to light the lamp for his studies.

“I was economically disadvantaged,” Abugbilla said. “Education was the key to change my family’s situation and my community.”

At 17, he participated in a French quiz competition in the regional capital of Bolgatanga. This day changed his life: It was the first time he saw a computer.

“At first, I thought it was a TV because of the desktop monitor,” Abugbilla laughed. “I needed to know how it worked and how I could use it.”

Later in high school, he looked over the shoulders of his classmates. He was mesmerized as they pounded keys and information magically appeared on the screen. He wasn’t confident enough to try. Until his instructor publicly shamed him.

“He said why can’t you do the basic things on a computer,” Abugbilla recalled. “My self-esteem was quite low.”

Determined to prove his instructor wrong, Abugbilla practiced typing with the help of a friend. Not long after, he bought his own Hewlett-Packard laptop as part of a scholarship he earned for his studies.

Becoming a global steward
Abugbilla excelled in his undergraduate studies at the University of Cape Coast, Ghana, where he earned a bachelor’s of education in French honors degree with a minor in English. But he had his sights on coming to America. He applied to the University of Arizona, Tucson and received a full-ride scholarship.

Francis Abugbilla

Francis Abugbilla, a Jackson School doctoral candidate, shares solar power with students in Ghana. Pictured is Francis giving a solar lamp to one of three winners of a global affairs competition that he initiated, September 2018.

As one of five to graduate from college in his village and the only one to obtain a master’s degree, Abugbilla was determined to climb the highest rung of education.

After completing his master’s degree in French, he applied for doctoral programs at 10 universities including the University of Washington’s Henry M. Jackson School of International Studies.

He received six acceptances with four full-ride scholarships. But the UW’s Jackson School stood amongst the crowd.

“I chose the Jackson School because of the accelerated nature of the program. It is not like the traditional doctoral program. I wanted to experience academia and the practical side of the policy world,” he said.

Abugbilla also received the Henry M. Jackson Doctoral Fellowship, funded by the Henry M. Jackson Foundation, that annually supports a deserving doctoral student with promising potential.

Finding a meaningful solution
Despite all his accomplishments, Abugbilla didn’t forget about the young people in his village.

“I had this idea of bringing electricity to my village through solar panels,” he said. “It was this daunting task. I didn’t know who to reach out to, where to turn, how would I fund this?”

Abugbilla shares a Ghanaian proverb: “The gods that look for yams for a child in the forest, will look for a hoe for digging the yams.” Where there is a vision, there is a provision, he explained.

In 2018, he found that chance thanks to the UW Marcy Migdal Fund for Educational Equality, a $1,000 fund supporting exceptional students engaged in finding meaningful solutions to global problems. With the support, Abugbilla installed a solar panel in the village school, allowing teachers to prepare lessons and students to have computer lessons and return to the school in the evening to do their homework. He also initiated an annual global studies competition in the school.The equipment installed include the Victron Energy Phoenix Inverter VE.Direct 500VA and  Victron Energy BlueSolar MPPT 75/15 

The Marcy Migdal fund is administered by the Center for Global Studies, which is housed at the Jackson School and is also a U.S. Department of Education National Resource Center. Students from all three campuses are encouraged to apply for the fellowship in February, with awardees announced in June.

Joel Migdal, professor of international studies who set up the Migdal fund in his late wife’s name said: “I couldn’t think of a project that my late wife, Marcy, who was an educator and social justice activist, would have found more meaningful than that of Francis’s. It brought tears to my eyes.”

Abugbilla continues to fundraise on GoFundMe to expand the solar panel project. He said he has been overwhelmed by the support he received from UW students, professors and others in the community.

“The Marcy Migdal fund was the tool to get me to dig the yam,” Abugbilla beamed. “It was the opportunity that opened more opportunities for me.” Tamara Leonard, Managing Director of the Center for Global Studies, added that the project exemplifies the kind of work that the Fund is intended to support.

Teaching others at UW and beyond
Shortly after initiating his solar power project, Abugbilla was invited to and participated in the Clinton Global Initiative University Annual Conference at the University of Chicago, an event honoring student leaders dedicated to addressing pressing challenges in the world. He also recently served as the keynote speaker for the 2019 Africa Now Youth Leadership Conference, an organization based in Seattle dedicated to inspiring African youth. In June 2019, he will attend the Global Youth Advancement Summit at the Michigan State University to talk about his solar power project.

Thanks in part to support from Carnegie Corporation of New York, in winter 2020 Abugbilla will help teach a course in the Donald C. Hellmann Task Force Program, an experiential learning capstone for undergraduate international studies majors. The Task Force, on energy interventions in Sub-Saharan Africa, will be led by Danny Hoffman, a professor in anthropology at the UW.

While Abugbilla plans on continuing his research at the Jackson School with a focus on peace, violence and security, his heart is still in Ghana.

“The goal is to electrify the schools  with solar power and then scale it up to the entire community,” he said. “It is important that people take their destiny into their own hands and effect the needed change in their lives. I want to spur them into thinking innovatively and outside the box.”

As just one of five in his village and in his family to graduate from college, and the only one to earn a master’s degree, Abugbilla is well on his way to propelling his community with solar power and the world forward.

Interested in learning more or supporting Francis’s “Empower Kids Through Technology” project? Click here.

About the author
Mary AndomMary Andom is a graduate student in the master’s in applied international studies program at the UW’s Henry M. Jackson School of International Studies and has a keen interest in immigration and national security issues. She spent eight years working in multinational environments in Germany, Hungary and Kyrgyzstan as a Non-Commissioned officer in the United States Air Force. Prior to enlisting in the military, Mary worked for various news organizations as a reporter and columnist for The Seattle TimesSeattle Post Intelligencer and The Chronicle of Higher Education.

 


Intersolar Europe 2019 is almost upon us and will be held at Neue Messe München from May 15-17, 2019.

As ever Victron Energy will be exhibiting. Our stand this year is number B2.480, where many new and updated products will be on display. Four key new products and one new product range are:

  • EasySolar-II 48/3000/35-32 MPPT 250/70 GX
  • MultiPlus-II 48/3000/35-32 230V GX
  • MultiPlus-II 48/5000/70-50 230V
  • Inverter RS 48/6000 230V Smart Solar
  • SmartSolar MPPT VE.Can range

These new products will be launched at Intersolar, however in this preview blog we can delve into a little more detail and compare the new models above with previous models where appropriate.

EasySolar-II 48/3000/35-32 MPPT 250/70 GX

Building on the existing EasySolar (which contains a MultiPlus Inverter/Charger and BlueSolar MPPT Solar Charge controller) this new model has a number of improved features and brings other welcome changes.

The EasySolar-II 3000VA GX (when compared to the earlier EasySolar) is based upon the Multiplus-II, giving the whole unit a more compact and modern design, along with improved standby power efficiency, reduced weight and volume.

The GX suffix indicates that there is a GX device for control and monitoring built-in. A GX device is usually a standalone device such as a Color Control GX, Venus GX, Octo GX or a CANvu GX – but in this instance it is a new integrated GX device, which is already connected to the internal Multiplus-II and MPPT charge controller.

In addition there is a small two line display showing what the unit is doing, and if relevant it can also show a detailed error code  – no more counting blinking LEDs!

The EasySolar-II 3000VA GX allows connection to CAN-bus battery management systems, the VRM remote data monitoring portal via Ethernet or built-in WiFi, enables ESS functionality, and much more.

Another update is the AC and DC rated circuit breaker protection is no longer supplied. This change is based on feedback from our customers who are now able to connect the EasySolar-II GX to their own AC and DC fuses or circuit protection – in other words that which is best suited to a particular application and any regional requirements.

The integral MPPT has had the input voltage increased from 150V to 250V, giving greater flexibility when choosing solar panel configurations. In addition, because the MPPT is Victron Smart, there’s all the usual VictronConnect App functionality people have come to expect from Smart enabled products.

If paralleling and using three phase with the EasySolar-II 3000VA GX, there can only be one GX device in such a system. Indeed one GX device is enough and therefore it does not make sense to buy three of the EasySolar-II 3000VA GXs and put them in a three phase installation. Instead what you do is buy one and then buy two normal MultiPlus-IIs with the same rating.

MultiPlus-II 48/3000/35-32 230V GX

This model is the existing MultiPlus-II 3000, with the addition of built-in GX features. It has all the advantages that you’ve come to expect from GX devices. We’ll keep both products in stock after intersolar Europe 2019.

Like the EasySolar-II 3000VA GX there is a small two line display showing what the unit is doing, and if relevant it can also show a detailed error code  – no more counting blinking LEDs!

Building a split- or three-phase system, or parallel system, with the MultiPlus-II GX models can be done. But there can only be one GX device in such a system. Indeed one GX device is enough and therefore it does not make sense to buy three of the MultiPlus-II 3000VA GXs and put them in a three phase installation. Instead what you do is buy one and then buy two normal MultiPlus-IIs with the same rating.

Another option is of course to use multiple normal MultiPlus-IIs, and then choose a GX device to your liking.

Below you can see the plethora of available connection options available on the GX version. Click the image to enlarge it.

MultiPlus-II 48/5000/70-50 230V

This new MultiPlus-II is simply a larger version of the existing 3000 version. See the product page and choose the datasheet to compare the new MultiPlus-II 48/5000/70-50 to the MultiPlus-II 48/3000/35-32.

Inverter RS 48/6000 230V Smart Solar

Yet another exciting new product, Victron Smart too.

Here are some key features of the RS 6000:

  • Built-in solar charge controller with 450V max PV input. Previously the highest max PV voltage of Victron Energy products was 250V. PV specification limits are 450V, 18A in, 4000Wp
  • Victron’s first all in one inverter+solar charge controller
  • HF inverter – a first for Victron Energy
  • Excellent voltage stability
  • Handy 4 x 20 character display display

The image below shows the bottom cover removed, to reveal various connections which include 1 x VE.Direct and 2 x VE.Can connections. Click the image to enlarge it.

Note: The Inverter RS 6000 cannot be configured for parallel operation nor three phase at present.

SmartSolar MPPT VE.Can

Last in the list of new products presented today is the SmartSolar MPPT VE.Can series.

There will be a series of 150V models available, as well as 250V. More detailed news will be shared in a future blog post after Intersolar Europe 2019 .

More information, pricing and availability

More technical information will be made available in the coming days and weeks: product pages, datasheets, and other documentation is being finished and made available on our website.

For availability and pricing, email [email protected]

Conclusion

As is often the case Intersolar  Europe 2019 serves as a launchpad for many new Victron Energy products. That doesn’t mean other new products aren’t released throughout the year – it’s simply that Intersolar Europe 2019 is one of the best places to see, learn and try the latest Victron products.

Oh! – And of course there’s Victron’s infamous Intersolar Stand Party to attend…

John Rushworth

Links

Intersolar Europe Website – https://www.intersolar.de/en/home.html

Intersolar Europe Facebook – https://www.facebook.com/Intersolar


Victron Energy CANvu GX …information you can touch! It’s so convenient to be able access all your system information via touch screen – and because the Victron Energy GX is a sealed-unit, you can install it in some challenging environments!

P67 rating of the Victron Energy  CANvu GX means that it is completely protected against dust ingress, and can even withstand half an hour’s immersion in water 1 metre deep!

The Victron Energy CANvu GX is the latest addition to the Venus family – the information gateway which allows you to set-up, monitor and manage all the component parts of your private energy installation. In exactly the same way as you use the CCGXVenus GX; and Octo GX – the Victron Energy CANvu GX gathers data from your Inverter/ChargerBattery MonitorSolar Charge Controller, and batteries to allow optimal communication between components, maximising battery-charging and solar harvest.

And, of course, it allows you to interrogate the status of each device. But amongst the whole family, it is the Victron Energy CANvu GX which is ideal when the information is required to be displayed outdoors, or in difficult environments.

The arrival of the Victron Energy CANvu GX will be welcomed particularly by those users who work in the open. It is entirely at home on board vessels at sea, or on building sites – in applications such as the control panel of Hybrid Generators. It is also ideal in factories where industrial processes are wet, or dusty.


The unit comes with a dash/fascia mounting kit:


Please note that in order to operate the Victron Energy  CANvu GX you will need an IO Extender and wiring kit, and that this must be ordered separately:

The full colour screen of the Victron Energy  CANvu GX will be familiar both in appearance and size to anyone who has seen or used the CCGX. The system offers 3 VE.Direct ports and one USB port; a second, separate CAN-bus port; and it can receive digital inputs. It doesn’t have a buzzer. WiFi is not built-in, but a USB WiFi dongle can be attached. A comparison of features between all members of the GX family can be found here.

Justin Tyers


Lithium SuperPack batteries – an all in one solution .These new Lithium-Ion, LiFePO4 chemistry batteries are often an ideal replacement for many 12V and 24V marine, automotive, caravan, motorhome, work vans and similar battery applications. It might even be for an overland motorcycle if using the smallest 20Ah version; to recharge a camera, phone or laptop for instance.

Other examples – take a typical small boat or van which may have a 110Ah to 220Ah lead-acid leisure battery for light continuous loads such as lighting, laptops, phones, instruments, powering a diesel heater, a fridge etc. And for shorter term loads maybe add a small inverter to charge power tools, run a small microwave or travel kettle for example. Using one SuperPack battery it matches well with the Phoenix Inverter VE.Direct 250VA – 1200VA range. Maybe you’ll add in around 100 to 200Wp of solar panels too using a small MPPT.

Regardless of the use, whichever SuperPack you choose it’ll be lighter than lead, can be smaller if you wish or give you more Wh in the same space – plus give you around 5 times the cycle life.

The main difference to Victron’s other lithium (often more kWh) offerings are the SuperPacks keep everything in one package, by having an integrated BMS and safety switch built-in. No additional components are needed as the internal switch will disconnect the battery in case of over discharge, over charge or high temperature. Simple, compact and safe.

If you are considering a new battery don’t immediately discount Lithium as being too costly. Whilst it is true that the capital cost of Li-ion is greater than that of quality AGM or Gel batteries – it is also true that the cost of ownership can be less than lead acid types. Much depends on your application, but rest assured – life with Li-ion is far less hassle than lead.

Over the last 8 years on my sailing yacht I’ve run AGM lead leisure batteries and Lithium-Ion propulsion batteries. Initially it was AGM for propulsion before discovering the effectiveness of Lithium. That journey taught me a lot about loads, capacity, cost and battery life – it’s one of the reasons why I think we’ve reached a tipping point and why these new SuperPack batteries may just be the ticket for your next project or battery replacement.

If in the first instance you are unfamiliar with AGM vs Lithium, then here’s a blog that explains that.

When to use a SuperPack?

Every battery size and type has it’s own particular use. For instance you may use the Lithium battery 12,8V & 25,6V Smart and the Lithium battery 24V (LiFePO4 & NMC chemistries) ranges (all of which have an external BMS) in quite different applications to the new SuperPack range. So, where to use the SuperPacks?

When it comes to replacing lead acid type batteries such as AGM and Gel in many applications, the SuperPack range can be considered the next generation after lead – making it far easier to replace lead with lithium. The only caveats being replacement is down to certain parameters being met, namely – Capacity (Ah), Voltages (12.8V & 25.6V), Discharge and Charge currents (C rates). Do in that case be sure that your chosen replacement fits your criteria by checking the datasheet and be aware the SuperPacks can be connected in parallel, but not in series. Hence in that case you would consider the other Victron lithium products named above.

The Lithium SuperPack

Victron Energy’s recently introduced Lithium SuperPack range comes in the following capacities and voltages:

12.8V & 25.6V Lithium SuperPack batteries:

  • 12.8V – 20Ah
  • 12.8V – 60Ah
  • 12.8V – 100Ah
  • 12.8V – 200Ah
  • 25.6V – 50Ah

These SuperPacks will give you 2,500 cycles to 80% depth of discharge at 25°C, much more than lead.

Comparison: SuperPack 60Ah LiFePO4 vs 90Ah AGM

Let’s compare the 60Ah Li-ion to say a typical 90Ah AGM battery discharged to the commonly accepted economic cycle life of 50% discharge for lead. That would give us 600 cycles at that DOD for the AGM compared to 2,500 at the even deeper discharge of 80% for the LiFePO4. Already you can see you may need to replace your lead-acid type battery 2 to 4 times as often as the Lithium. Of course loads, operating conditions and calendar life have to be factored in too. Regardless you get the idea – Lithium does more and lasts longer.

The benefits of Lithium don’t stop there though. Whilst LiFePO4 chemistry is considered the safest of them all, it’s worth considering other factors too to decide whether the reduced weight and volume of say NMC is of more importance for your application than LiFePO4 for example. Victron Energy do both types. These star graphs do a good job of explaining the differences: https://batteryuniversity.com/learn/article/types_of_lithium_ion

60Ah SuperPack

90Ah AGM

Weight
9.5kg 27kg
Size (mm)
229 x 138 x 213 350 x 167 x 183
Useable energy @ 25°C
614Wh 540Wh
Cycle life
2,500 cycles 600 cycles
Cost
x 2.5 (approx)  x 1

Notes for the table above:

  • Useable energy and cycle life are based on 80% depth of discharge for Li-ion and 50% for AGM, these being considered the most economic use of those battery types.
  • Higher loads with lead will further reduce available Wh (Peukert’s Law) when compared to Li-ion.
  • Capacity is also reduced for both types by temperatures below their 25°C temperature rating (see their respective datasheets)

Make what you will of the above and whilst you are pondering the pros and cons don’t forget to take these additional factors into account for the comparison above.

  • Shipping: If you are replacing your lead from 2 to 4 times as often as Li-on and the fact that the lead weighs around 3 to 4 times as much (depends on Li-ion chemistry used) – then do consider the extra shipping costs.
  • Voltage stability: The voltage profile is far flatter for Li-ion compared to lead.
  • Voltage sag: Subject to the load, voltage sag with lead is significant compared to Li-ion.
  • Li-ion has much faster charge times and if charging from a generator it saves on generator runtime.

Other factors to consider

Is the above enough to convince you of why Lithium might be a better alternative than AGM or indeed Gel? Personally I’m sold on Lithium, but if you are not here’s a few things further to consider:

  1. A lead-acid battery will fail prematurely due to sulfation if it operates in deficit mode for long periods of time (i.e. if the battery is rarely, or never at all, fully charged). It will also fail early if left partially charged or worse, fully discharged.
  2. By comparison a Lithium-Ion battery does not need to be fully charged. This is a major advantage of Li-ion compared to lead-acid which needs to be fully charged often to prevent sulfation.

  1. Efficiency. In several applications (especially off-grid solar), energy efficiency can be of crucial importance. The round-trip energy efficiency (discharge from 100% to 0% and back to 100% charged) of the average lead-acid battery is 80%.
  2. The round-trip energy efficiency of a Li-ion battery is 92%.

  1. The charge process of lead-acid batteries becomes particularly inefficient when the 80% state of charge has been reached, resulting in efficiencies of 50% or even less in solar systems where several days of reserve energy are required (battery operating in 70% to 100% charged state).
  2. In contrast, a Li-ion battery will still achieve 90% efficiency even under shallow discharge conditions.

Make the switch?

Are you ready to make the switch from Lead to LiFe? If you’ve considered all the above I suspect you might be. And if you need more useable Ah why not run the sums on say a 100Ah Lithium SuperPack vs 220Ah AGM using the process I have above. Or indeed a 200Ah Li-ion SuperPack vs your choice of lead.Lithium SuperPack batteries – an all in one solution

Don’t forget too that Lithium has little or no Peukert effect when compared to Lead types. This is especially important when considering loads with lead-acid higher than 0.05C (Battery Ah divided by 20 or Ah multiplied by 0.05). In other words for a 100Ah AGM with a Peukert of say 1.15 or more and discharging at 0.25C (25 Amps in this case – which is 5 times the 20 hour rate) there will be significant reduction in capacity – as there will be at colder temperatures too. Li-ion has a Peukert of around 1.05 when compared to lead of around 1.15 to 1.25.

So – if you were discharging that 100Ah lead at 5 Amps (the 20 hour discharge rate at a temperature of 25 degrees centigrade) then the full capacity of 100Ah is still availaable and it’s not shrunk due to Peukert. But now if it were 0.25C, it’ll be around 80% of that original 100Ah capacity – or less, subject to load type and duration.Lithium SuperPack batteries – an all in one solution

The bottom line is you no longer have the Ah you purchased, whereas with Lithium there is little to no effect, helped by a lower Peukert and good voltage stability. That is especially important with constant inverter loads – a place where lithium shines. If you want to learn more about Peukert and run a spreadsheet to see such effects, then I have found this link most helpful.

Finally and one I’m always grateful of is vastly reduced charge times, no more waiting for hours of lead absorption charging to get from 80% to 100% SOC. Conversely Li-ion flies up to around 98% SOC in bulk with those last few percent in absorption to fully balance the cells – and unlike lead you don’t always have to fully charge to 100% as often. Note that your 12V charging system needs to accommodate 14.2V – 14.4V ‘absorption’ and ‘13.5V’ float. If charging from an alternator also note the maximum continuous charge currents for the 12.8V range, by checking the datasheet.

Downsides

Not wanting to sound too evangelical, we also need to consider the few downsides of Li-ion.

  • Higher upfront cost and to some extent higher capital risk.
  • Charging is restricted to the +5°C to +45° range, subject to an internal means of blocking the charge source when the temperature is below +5°C. Note this is currently automatically possible with Victron MPPTs when used in conjunction with the Smart Battery Sense for instance. Other products are being worked on to achieve this too and documentation to that effect will be updated in due course.
  • The SuperPack (unlike other Victron Lithiums) is not designed for series connections.
  • The peak and maximum continuous discharge current of the SuperPack range is not as much as some of our Lithium batteries as its related to the BMS and the disconnect being internal to the battery – so do check the datasheet to make sure the current peak and discharge ratings suit your needs – or choose from the Lithium battery 12.8V & 25.6V Smart or the Lithium battery 24V range or build a parallel SuperPack bank.Lithium SuperPack batteries – an all in one solution

Conclusion

Whatever your decision when purchasing new batteries, maybe it is time to give the Lithium SuperPack batteries a chance. There’s LiFe after Lead you know – but as I’ve shown that all depends on what you want to achieve. Is it less weight, less volume, maybe it’s capacity or voltage or any of the multitude of factors that go into choosing a battery system.Lithium SuperPack batteries – an all in one solution

Whatever you choose Victron have plenty of choice – with a large range of battery types and sizes: https://www.victronenergy.com/batteries

John Rushworth


Lithium-ion vs AGM Battery has been a very popular topic in independent power circles in recent times In light of my last post concerning the use of the DC or Hybrid concept for electrical power, it occurred to me that the system could also have used monobloc AGM/Gel batteries or indeed a bank of long life 2 volt gel cells. In that case why was Lithium chosen? Hopefully this post may go some way to highlighting that decision process.

Across all markets over recent years Lithium-ion batteries have been gaining in traction . To the uninitiated it is easy to dismiss Lithium-ion as an expensive alternative to VRLA (valve regulated lead acid) technologies such as AGM (absorbed glass mat), if simply looking at the amp-hour (Ah) rating. This was the initial mistake I made a few years back. Digging deeper it became clear to me that there is a lot more than Ah ratings to consider, when choosing the best batteries for your application.Lithium-ion vs AGM Battery

In the marine world (which is where I have the most experience) the choice these days and especially with higher loads – often simply comes down to Lithium-ion vs AGM Battery. In the comparisons below whilst Gel batteries are shown, they do have a lower effective capacity at high discharge currents.  They cost about the same as AGMs, assuming both types are monoblocs, as opposed to 2 V long life gel cells. Wet cell or flooded lead acid (FLA) batteries whilst referred to are not considered for the crux of this particular comparison, primarily due to maintenance and safety considerations in the marine environment. This of course may not apply to other markets.Lithium-ion vs AGM Battery

Useable energy and cost

It is generally accepted that the most economic and practical depth of discharge (DOD) for an AGM battery is 50%. For Lithium-iron-phosphate (LiFePO4 or LFP) which is the safest of the mainstream Li-ion battery types, 80% DOD is used.

How does this work out in the real world? Let’s take two Victron 24V battery examples and compare useable energy for a small yacht:

  • 1 x Victron Lithium-ion 24 V 180 Ah

The nominal voltage of the LFP cell is 3.3 V. This 26.4 V LFP battery consists of 8 cells connected in series with a 180 Ah rating. The available energy is 26.4 x 180 = 4. 75 kWh. Useable energy is 26.4 x 180 x 0.80 = 3.8 kWh.

  • 2 x Victron AGM 12 V 220 Ah

The nominal voltage of the lead-acid cell is 2.0 V/cell. Each 12 V monobloc battery consists of 6 cells connected in series with a 220 Ah rating. Connecting 2 x 12 V 220 Ah batteries in series to give 24V and 220 Ah, the available energy is 24.0 x 220 = 5.28 kWh. Useable energy is 24 x 220 x 0.50 = 2.64 kWh.

This begs the question, what Ah rating of AGM batteries would be the equivalent of the 3.8 kWh useable energy of the Lithium-ion battery? To get 3.8 kWh of useable energy from an AGM battery it would need to be twice that size to start with due to the 50% DOD economy rule i.e. 3.8 x 2 = 7.6 kWh. At 24V that would mean 7,600/24 which gives us a battery rating of 316.66 Ah, which is moving closer to twice the rated capacity of the Lithium-ion 24 V 180 Ah. Note this does not take into account, the ageing of the batteries, temperature derating or the effect of higher loads. For AGM batteries, higher loads have a greater effect than on Lithium. See the section – Useable energy: effect on discharge capacity and voltage with differing loads, below. Based on all this it is reasonable to say that an AGM battery will need to be twice the Ah rating of a Lithium one.

What about price? Using the Victron price list we see that a 12V 220 Ah AGM is € 470 ex VAT or 2.136 €/ Ah. For 316.66 Ah that is the equivalent of € 676.50 at 12V or € 1,353 at 24 V. The 24V 180 Ah Lithium is € 4,704 for the same amount of useable energy and is therefore 4,704/1,353  = 3.48 times more expensive (or less if we consider the factor of 2 referred to above) when comparing Ah ratings.

 

Based on this you might immediately conclude that Lithium is not cost effective, however useable energy compared to price is only part of the story.Lithium-ion vs AGM Battery

Usable energy

 

Weight

Most Ah ratings of batteries regardless of type are specified at the 20 hour rate. This was fine in the days of light loads, but as the number of loads and the size of loads has increased over time, we also need to look at high short term loads, medium and longer term ones for differing types of equipment. This can mean a large battery pack. At the extremes we might have air conditioning running for 10 hours using 10 kW, compared to an LED light using 100 Watts in that time. Balancing these differing requirements and all the loads inbetween becomes key. With a large pack as shown below to achieve this, it becomes clear just how heavy Lead Acid can be compared to Lithium. 1360/336 = 4 times heavier.

Weight

 

Useable energy: effect on discharge capacity and voltage with differing loads

As stated earlier most batteries Ah rating are quoted at the 20 hr rate. In the image below for the lead acid battery, if that were a 100 Ah battery at the 20 hr rate, you can see that 0.05C means 100 x 0.05 = 5 Amps for 20 hours = 100 Ah available until the battery is totally flat. As we use only 50% of the battery we can see that the voltage will still be 24 V at 50% DOD for a 5 Amp load over 10 hours, and therefore we would have consumed 50 Ah.

Increasing the current draw (as the graphs below show) can affect the useable energy available and battery voltage. This effective shrinkage in the rating is known as Peukert’s effect. With lead acid the higher the load, the more you need to increase the Ah capacity of your battery to help alleviate this. With Lithium however a load  of even 10 times greater at 0.5C can still have a terminal voltage of 24V at 80% DOD/20% SOC, without going up on the Ah rating of the battery. This is what makes Lithium particularly suitable for high loads.

Note: In the graphs below Discharge Capacity vs Terminal Voltage is shown. Usually you will see AGM graphs as Discharge Time vs Terminal Voltage. The reason we plot Discharge Capacity (instead of Discharge Time) is that Lithium has a higher and more stable terminal voltage than AGM, so plotting the curves with Discharge Capacity in mind gives a more accurate comparison of the chemistries, showing that Lithium increases useable energy at higher loads due to higher and more stable terminal voltages. Whilst you may consider this a grey area (in part too due to the varying internal resistance of batteries also) it is probably the only true way to compare the technologies. This is further demonstrated in the images below the graphs.

Lithium – Discharge Capacity vs Terminal Voltage

LithiumLead Acid – Discharge Capacity vs Terminal Voltage

Lead_Acid, Lithium-ion vs AGM BatteryUseable Energy (Lead Acid)

Useable_Energy_Lead_Acid

Useable Energy (Lithium)

Useable_Energy_Lithium Lithium-ion vs AGM Battery

 Charge Efficiency

Much that we have seen in the discharge process is also true in the converse process of charging. Don’t be put off by the large generator sizes shown below, as this blog merely shows a range of scenarios. Solutions are scalable in principal. First let’s compare charge efficiency of Lead Acid on the left to Lithium on the right, during the complete charge cycle. Charging the last 20% of a lead acid technology battery is always slow and inefficient when compared to Lithium. This is borne out in the fuel costs (or whatever charging source you use) in the images further down. Note the difference in charge times too.

Note: Charge rates

The recommended charge rate for large size AGM batteries is 0.2C  i.e. 120A for a 600A battery consisting of paralleled 200Ah blocks.

Higher charge rates will heat up the battery (temperature compensation, voltage sensing and good ventilation are absolutely needed in such a case to prevent thermal runaway), and due to internal resistance the absorption voltage will be reached when the battery is charged at only 60% or less, resulting in a longer absorption time needed to fully charge the battery.

High rate charging will therefore not substantially reduce the charging time of a lead-acid technology battery.

By comparison a 200Ah Lithium battery can be charged with up to 500A, however the recommended charge rate for maximum cycle life is 100A (0.5C) or less. Again this shows that in both discharge and charge that Lithium is superior.

Charge_Efficiency Lithium-ion vs AGM Battery


Charge_Efficiency2 Lithium-ion vs AGM Battery


 

Charge_Efficiency3 Lithium-ion vs AGM Battery

Battery choices, markets and cycle life

Depending how you treat a battery you can reasonably expect the range of cycles below, subject to the DOD and the battery banks being properly sized for the loads. Operating temperature also comes into play. The hotter the battery the less time it will last. Battery capacity also reduces with ambient temperature. The baseline for variations due to temperature is 25 degrees Centigrade.

Battery_Cycle_Life


Battery_Cycle_Life2 Lithium-ion vs AGM Battery


Battery_Cycle_Life3 Lithium-ion vs AGM Battery

 

Conclusions

Clearly AGM batteries will need to be replaced more often than Lithium. It is worth bearing this in mind as this entails time, installation and transportation costs, which further negates the higher initial capital cost of Lithium as does the lower cost of recharging Lithium.

No matter what battery choice you make there is also both a capital cost and technological risk at the outset. If you are in a position of having the capital for the higher upfront costs of Lithium, you might find that life is easier and that choice is a cost effective one over time. Much of this depends on the knowledge of the operator and how they treat a battery system. There is an old saying that batteries don’t die, they are killed. Good management practices are your insurance against early failure, regardless of the technology used.

Lithium-ion vs AGM Battery? The choice is yours. Personally I think the time is right to consider Lithium in the marine industry as a cost effective, reliable, high performance solution. Last week (it was only out of curiosity you understand) I went for a test drive in a Lithium-ion powered Tesla Model S – and as we know, no self-respecting electric vehicle manufacturer would still use lead acid based battery technologies today. Time for the marine industry to catch up with the Lithium-ion vs AGM Battery debate?

John Rushworth

Credits

Thanks to Reinout Vader and Johannes Boonstra for the images and technical advice in writing this blog.

Further reading

Whitepapers, inc Energy Unlimited by Reinout Vader:  https://www.victronenergy.com/support-and-downloads/whitepapers

Battery choices: https://www.victronenergy.com/batteries

 

 

 

 

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