How to choose the best Solar battery in Ghana

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victron energy phoenix inverter compact in a box-bluepower+fronius lithium battery-agm vs lithium

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.

https://www.youtube.com/watch?v=CIVBpSs2ma0

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.

Lead acid battery charging in cold weather

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Lead acid battery charging in cold weather

This blog covers lead acid battery charging at low temperatures. A later blog will deal with lithium batteries.

Charging lead acid batteries in cold (and indeed hot) weather needs special consideration, primarily due to the fact a higher charge voltage is required at low temperatures and a lower voltage at high temperatures.

Charging therefore needs to be ‘temperature compensated’ to improve battery care and this is required when the temperature of the battery is expected to be less than 10°C / 50°F or more than 30°C / 85°F. The centre point for temperature compensation is 25°C / 77°F.

Cold weather also reduces a battery’s capacity. This is another factor that needs to be taken into consideration, along with the load and charge rate compared to the battery capacity (Ah). Both of these factors affect the correct and consequent sizing of a battery for your particular application.

Battery capacity in Ah is usually quoted as a 20 hour capacity rating at 25°C. The discharge rate or load can be written as 0.05C where for example C is the load factor of the 20 hour rated battery capacity at 25°C.

Worked examples: If a 100Ah 20hr rated battery then a 0.05 load would be 100 x 0.05 = 5 Amps or 100/20 which is also a 5 Amp discharge rate over that 20 hour period. A 10A load on a 100Ah 20 hour rated battery would therefore be a 0.1C discharge rate, a 0.2C discharge rate on a 200Ah would be 40A and so on. C ratings also relate to charge rates as well as discharge rates.

When buying a battery you may see its Ah quoted at 20 (the standard rate), 10 and 5 hour rates so you can see how load ‘shrinks’ the Ah. Some even quote at 25 hour rates, which often fools people into thinking they are getting a bigger battery than standard.

To recap – capacity reduces at low temperatures, as it does for higher discharge C rates above the 0.05C 20 hour rate. This reduction in capacity due to higher discharge rates is due to Peukert’s Law.

Graph showing the effect on battery capacity due to temperature and load:

Lead acid battery differences

Lead acid batteries come in a variety of types:
  • Wet lead with the ability to top up each of the six cells with de-mineralised water.
  • The so called ‘sealed’ wet lead leisure or rather maintenance free battery. These cannot be topped up and often have a green go or red no go cell inspection indicator.
  • AGM (Absorbent Glass Mat) valve-regulated lead-acid (VRLA), where the electrolyte is absorbed in a glass mat.
  • Similar to the AGM, but the electrolyte is held in a Gel.

All of the above are however lead based (as opposed to lithium) technology. Besides lithium batteries Victron Energy sell VRLA AGM and Gel monoblocs (6 x 2V cells in series) due to their superiority over wet lead monobloc types. Victron’s range consists of:

  • Gel (Better cycle life than AGM).
  • AGM (Better than Gel for higher loads and well suited for use with inverters).
  • AGM Telecom. Designed primarily for Telecom applications, but also excellent ‘footprint space savers’ for marine and vehicle applications.
  • AGM Super Cycle (Best if frequent discharge to 60-80% DOD is expected).
  • Lead Carbon Battery (Improved partial state-of-charge performance, more cycles, and higher efficiency).

Additionally Victron also sell specialist lead acid type batteries.

  • OPzV 2V individual battery cells. Long life, high capacity gel.
  • OPzS 2V individual battery cells. Long life high capacity flooded tubular plate batteries for specialist solar applications.

Temperature compensation and charging

Now we know about the kind of batteries, capacities and loads we are dealing with, we need to put some numbers together for temperature compensation and charging.

The recommended temperature compensation for Victron VRLA batteries is – 4 mV / Cell (-24 mV /°C for a 12V battery).

Besides accounting for cold weather charging the charge current should preferably not exceed 0.2C (20A for a 100Ah battery) as the temperature of the battery would tend to increase by more than 10°C if the charge current exceeded 0.2C. Therefore temperature compensation is also required if the charge current exceeds 0.2C.

How to achieve temperature and voltage compensated charging

There are a range of Victron products to achieve this.

With our range of inverter/chargers and since VE.Bus firmware version 415 was released some time back this has ensured that:

– Temp compensation continues down to -20C

– This is for all voltage set-points, except for float, storage and the start of bulk charging

– As soon as the temperature goes below -30C, the compensation mechanism is disabled (normal charge voltages are applied) and a warning is shown.

For systems that don’t use an inverter/charger – we can use Smart Battery Sense to ensure that charging sources provide optimal voltage and temperature compensated charging to your batteries, by wirelessly transmitting accurate battery voltage and temperature values to your Solar Charge Controller or Smart battery charger.

This information is then used to set the ideal charging parameters, resulting in more complete, faster charging – improving battery health and therefore extending battery life.

The Victron Toolkit app allows you to calculate cable sizes and voltage drop. Here’s an example where cable length is the round trip of the positive and negative battery charging cables. This is so you get an idea of what Smart Battery Sense automatically takes into account to ensure the correct charge voltage goes into the battery, by ensuring the charge voltage is compensated for and corrected due to any cable losses.

Victron’s range of SmartSolar MPPT Charge Controllers all work with the Smart Battery Sense. In fact I’ve just fitted one to my motorhome, along with the required Smart Battery Sense, due to the fact the leisure battery temperature location when compared to the location of the controller can have a difference of up to ten degrees. Definitely a case for ensuring accurate temperature compensation.

Other products can be connected too by using what we call ‘VE.Smart Networking support’. See the VE.Smart Networking page.

Conclusion

With the above solutions I know I’ll be happier now that my batteries are getting exactly the right charge due to optimal temperature and voltage compensation.

Why not make sure you are doing the same…

John Rushworth

Why Lithium-Ion Batteries Could Be A Game Changer

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Shrimp to Spark Flow Battery Storage Revolution

Lithium-ion batteries in Renewable energy resources – such as wind, water or solar solutions – hold great promise. They could provide energy while overcoming Africa’s infrastructural challenges. But this energy would still need to be stored. Lithium-ion batteries might provide a solution. The Conversation Africa asked Bernard Jan Bladergroen about the challenges and opportunities.

What are lithium-ion batteries and what are its benefits?

Lithium ion, or Li-ion, batteries are a type of rechargeable battery. They are a popular choice because when well looked after, they can be drained and charged literally thousands of times which makes them superior to commonly used lead acid batteries.

Lithium-ion batteries – like other batteries used to store energy – act as a buffer between power generation and consumption. The batteries are charged when power is available from, example, a wind turbine, solar panels or the grid, and then provide power when it’s not.

If Lithium-ion batteries could be manufactured in Africa, on the appropriate scale, they would become cheaper and power users could rely more on renewable energy than they do now. This would open the path for clean, sustainable energy, mitigating the effects of climate change. It could also boost economies.

Africa already has part of the solution: photovoltaic (PV) panels are common and the energy they produce in South Africa is approximately  40% cheaper than that generated from fossil or nuclear fueled power stations. The main drawback of PV power is that it can only really be generated between 5-7 hours daily (depending on what part of the continent one is located. That’s not when most people need to use it, so it has to be stored cheaply.

Lithium-ion batteries have been commercialized elsewhere in the world. Why not in Africa yet?

Li-ion batteries are used in many commercially available products, like power tools, toys, electric bikes, laptops and mobile phones. Large Li-ion battery packs in home and grid-power applications are becoming rapidly more popular in many countries, including Africa.

There are only a few Li-ion battery factories in the US, Poland, South Korea, Japan and China. Most of the companies that run them work closely with electric vehicle manufacturers and consumer good production sites. Some of the top 10 companies manufacturing the batteries include; Panasonic, Toshiba, Samsung SDI, LG-Chem and Tesla.

There are a few small companies in South Africa who assemble battery packs using imported cells. And, to the best knowledge of the author, there’s only one facility on the African continent that has the capability to produce Li-ion battery cells at pilot scale: the University of the Western Cape’s Energy Storage Innovation Lab. The lab has already been laying the groundwork for industrial Li-ion batteries assembly. Though I cannot say with certainty that Li-ion cells are not being produced elsewhere in Africa, it would be hard for a commercial plant to go unnoticed as it would have to be very large to be profitable.

freedom won lithium-ion battery installed in Accra

There is huge opportunity. South Africa has almost 80% of the world’s known reserves of manganese – an important component of the most popular battery. Because the companies that produce Li-on batteries have deep pockets, and because the price of manganese is relatively low, they have been able to import it from South Africa.

A growing market will eventually justify the creation of a local battery production plant. But to produce batteries at a competitive price, a large scale facility with an investment of at least $1 billion is required. Only in a facility that produced millions of excellent quality cells per day would the cost per cell be able to compete with cells produced on other continents. It will be challenging to raise the required capital in Africa.

What would be the major challenges in commercializing Li-ion across the continent?

To achieve commercialization across the continent, the cost of a Li-ion battery system needs to be lower than any alternative energy storage system. Currently, Li-ion batteries cost between $500-$1000/kWh, significantly more than Lead Acid batteries, but since they last much longer than Lead Acid, they can offer a better deal.

The desired shift away from our unsustainable fossil-fuel-based economy can be realized when we produce Li-ion batteries that last many years and cost as little as $300/kWh. Economy of scale is crucial to achieve these costs.

The electrification gains could be huge. Renewable energy – such as wind or solar solutions – combined with an energy storage device that could deliver electricity at the cost of electricity from a power station would be a game changer. And because Africa’s power distribution network is still underdeveloped, investors in the device could see returns sooner than in regions with a fully developed transmission network that’s already paid for.

Why do solar street lights fail in Ghana

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Why do solar street lights fail in Ghana ?Why are our streets so dark? Why are we not seeing working solar street lights in our streets today?

The answer is simple: some stand-alone solar street lights cause more problems than they solve. In some cases they don’t solve any problems at all.In Ghana a lot of streetlights are installed during  the election year ,streets are kept lit constantly and then all of a sudden the lights go out and never come on again.In recent times regular streetlights have been replaced with stand alone solar streetlights and some of them are quite fancy.

Smart Solar Street Light installation in Antigua and Barbuda

The real question is still whether this technology is economically feasible right now or whether we should wait for technology to evolve further before we take the inevitable plunge.The question of feasibility has reared its head due to bad decisions on the implementation of inadequate solar
components combined with “quick fix” solutions versus sustainable, long-term solutions.
The solar street light is a prime example of this. How many solar street lights have you seen that are not in working order? If you haven’t seen any solar street lights at all, it may be that the local municipality has not been convinced of the feasibility of these systems because so many systems have failed to date.
The solar street light is mostly sold as an LED street light with a battery box and a solar panel mounted on top of a 6 – 9 m pole. This is known as a “stand-alone” solar street light. The theory is that the solar panel will charge the battery during the day and, at night, the light will use the power stored in the battery to provide light.This idea should be considered a match made in heaven and a solution to many problems: streets lights use a lot of electricity and eliminating even only half of this consumption would lighten the strain burden on the grid. LED has a much longer life expectancy, so maintenance costs on the lights should
be minimal. So why do we not see this exciting development in our streets today? The answer lies with a combination of quality and longevity and with an understanding of the products.

Victron Energy’s highly efficient, ultra fast MPPT Solar Charge Controllers provide more efficiency in solar street lighting

The lighting units use quality components. The solar panels are 24% efficient (about as good as you can get commercially) and the LED lights are among the best at 160 lumens per watt (lm/W). The more lm/W a lamp produces the more efficient it is.A traditional incandescent light is around 15 lm/W, an energy-saving fluorescent bulb is around 60 lm/W. Easy then to see the attraction of solar power for free and lamps that are over 10 times as efficient as old fashioned bulbs – all which nicely meets companies requirements for improvements in sustainability and efficiency.

EnGoPlanet Inc ,a New York based company chose to use Victron Energy’s highly efficient, ultra fast MPPT Solar Charge Controllers, plus Victron batteries together with lighting options such as:

  • Wireless internet connection for remote control and management.
  • Smart Cameras.
  • Sensors for collecting various environmental data.
  • Mobile phone charging stations.

Their Smart Solar Street Lights are used in the Kuwait project, where 140 units have been installed. Petar Mirovic, CEO of EnGoPlanet tells me that the success of the project has interested other oil companies too, such as Saudi Aramco who are considering an installation of over 1,000 units in the coming months.

Well – that all sounds to me like a recipe for success!