SOLAR BATTERIES: LUMIUM OR LEAD-ACID

The Differences Between Lead Acid and Lithium Batteries

What batteries for Solar


New solar power generation systems have received a lot of attention lately, despite the concept of energy storage having been around for decades. There has been a dramatic increase over the last few years in the number of homes and businesses transitioning off the grid, and their upward trajectory shows no signs of slowing down. Solar energy systems, comprising a million homes of 2.5 gigawatts, have been installed in Canada in 2016 - which is equivalent to 2.5 gigawatts.

Solar battery technology has also grown significantly, as a result of the worldwide popularity of solar energy. The energy storage systems used today are bigger, better, and more environmentally friendly than ever before.

The main storage device for solar energy was traditionally nickel-based batteries, used by both home and business owners. Lithium-ion and lead acid batteries are the current battery types that are more efficient and better than what was available a few years ago.

As we progress through this article, we will examine how lithium-ion and lead acid batteries compare with one another after solar energy has been generated.

SOLAR BATTERIES: LITHIUM-ION VS LEAD-ACID: THE BASICS

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You can choose from three main varieties of batteries when you build your solar generation system:

LITHIUM


Lithium Iron Phosphate (LFP/LiFePO4) batteries are the best lithium battery chemistry for use in solar applications. The longer lifespan makes it possible to put this new technology through more cycles. In addition, lithium-ion batteries do not need to be vented or maintained because they do not contain lead acid.

Over the lifetime of the batteries, lithium batteries, despite having higher initial costs, are potentially more cost-effective than traditional batteries due to their superior capacity efficiency.

FLOODED LEAD-ACID (FLA)


FLA batteries are distinguished by having submerged electrodes, or "plates" as they are called in common parlance. Ideally, FLA batteries should be inspected and refilled once every one to three months in order to perform optimally.

Batteries whose maintenance is not properly performed can have their warranties voided and their lifetimes reduced dramatically. Further, FLA batteries require a ventilated enclosure in order to avoid battery gases condensing inside.

SEALED LEAD-ACID (SLA)


Gel and absorbent glass mat (AGL) batteries are the two most common types of SLA batteries. Neither of them requires much maintenance, have spill-proof properties, or are spill-proof. Generally, gel batteries have a lower capacity and rate of charging than AGM batteries. It typically takes them longer to recharge and they are less powerful since they cannot handle as much charge current.

The Cost of Lithium-ion and Lead-Acid Solar Batteries


In comparison to lithium-ion batteries, lead acid batteries are much cheaper up-front. Compared to a lithium-ion setup of similar size, a lead acid solar battery system may be hundreds or thousands of dollars cheaper.

The balance of power remains roughly balanced regardless of whether lead-acid batteries or lithium ion batteries have lower purchase and installation costs.

Comparing LITHIUM-ION and LEAD-ACID Batteries


Let's look at how these two batteries compare now that we've given you a basic understanding of how they work. In comparison to each other, the following principles are different.

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CYCLE LIFE


In the process of emphasizing the charging of a battery through solar panels, during which electricity is first discharged (used to power appliances), a single charge cycle is created. We measure battery life in terms of how many charge cycles a battery can handle before it dies, not in terms of how long it lasts. Putting miles on a car is similar to this concept. The odometer reading is a much more important feature to consider in evaluating the condition of a pre-owned car than its year of manufacture, isn't it?

Likewise, batteries and the amount of charge cycles they've experienced should also be considered. Despite using the same setup at your home and vacation home per year, an SLA battery at your vacation home may only have experienced 100 cycles within five years. There is no point in trying to figure out which setup is better. Also, the cycle life of batteries is determined by how deep they are discharged (how much capacity they use before they are recharged). Battery life shortens as you deep discharge it, as it is stressed more and has a shorter cycle  life. 

Stanford scientists carried out a study on grid-scale battery technologies in order to calculate their carbon footprint. They designed a new method for quantifying long-term energetic costs

Energy stored on investment, or ESOI, is the formula they developed. This is a measure of ESOI. Divided by the energy needed to build an object, the energy that can be stored by a technology. ESOI measure shows how energy efficient a storage technology is in relation to other storage technologies. 

With an ESOI score of 10, lithium-ion batteries were the best performers. Battery with lead-acid had an ESOI of 2, the lowest among all battery types studied. Then, a traditional lead-acid battery can only store twice as much energy as its own production required.

EFFICIENCY


Lithium-ion batteries are significantly more efficient than lead-acid batteries in terms of energy storage. Therefore, you will be able to store and use more of the solar energy.

Based on the condition and the model, lead acid batteries are only 80 to 85% efficient.  After the charging and discharging process, there will be 800 to 850 watts of available solar energy if you have 1000 watts of solar power coming into the batteries.

In contrast, lithium-ion batteries have a higher efficiency rating of more than 95%. Therefore, your power supply would be able to provide more than 95 watts.

DEPTH OF DISCHARGE


A deep discharge means using up the maximum capacity of a battery before it is recharged, as we've just discussed. A battery's depth of discharge would be 50% if half of its capacity is used. 

Lithium-ion batteries have a higher usable capacity than most other batteries because they can handle deep discharges up to 80%.

Lead-acid batteries, on the other hand, are said to perform better if no more than 50% of their charge has been dissipated. Batteries can be negatively affected by discharging them beyond this point.

Charge times are sped up as efficiency increases. In addition, it may prevent you from purchasing many panels and a larger generator depending on your system's configuration.

CHARGE RATE


In addition, lithium-ion batteries are capable of handling higher charging currents. Because they can be refilled more quickly, they are more convenient than lead-acid batteries.

The charging current which lead acid batteries can handle is limited. The reason is that if charged too soon, they start to overheat. In addition, when you reach full capacity, the charging rate decreases considerably.

High Temperature Battery Performance


When it comes to high temperature applications, lithium outperforms SLA hands down. A lithium cell at 55°C will still have twice the cycle life of a lithium cell at room temperature. When exposed to elevated temperatures, lithium is superior to lead in most conditions.

Cold Temperature Battery Performance


All battery chemistries are significantly reduced in capacity at cold temperatures. For this reason, when comparing batteries for extreme cold, four factors are important to consider: charging and  discharging. Low temperatures (below 32 F) don't allow lithium batteries to receive a charge. Low current charges can, however, be accepted by an SLA at low temperatures.

Lithium batteries, on the other hand, have a higher discharge capacity at cold temperatures than SLA batteries. So it is not necessary for lithium batteries to be overly designed for cold temperatures, but charging might be a problem. SLA discharges at 45% of its rated capacity at zero degrees F while lithium discharges 70% of its rated capacity.

Whenever you want to charge your lithium battery it is a good idea to keep in mind the state of the battery in a cold environment. The battery will be able to accept a charge from the charger if it has just been charged after being discharged. If the battery was allowed to cool down before being charged, the battery might not accept a charge if it is below 32 degrees.

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EFFICIENCY


Lithium-ion batteries are significantly more efficient than lead-acid batteries in terms of energy storage. This means you use and store more solar energy.

Based on the condition and the model, lead acid batteries are only 80 to 85% efficient. As a consequence, if you have 1,000 watts of solar power entering your battery, after charging and discharging you will have up to 850 watts left.

ENERGY DENSITY


There will be a noticeable weight difference between a lithium-ion and a lead-acid battery of the same capacity. Although most installers aren't going to run into this issue, if you are installing the batteries yourself, it may be quite challenging.

However, there is a cost associated with this. Lead acid batteries have a lower battery density than lithium-ion batteries. The space you have is therefore used more efficiently. The power of a 5.13-kilowatt system can normally be provided by eight lead acid batteries. However, you could accomplish the exact same task with just two lithium-ion batteries. So, when you consider the size and weight of the entire battery bank, you will see that lithium batteries weigh 2.35 times as much as lead-acid batteries. When working with a limited space, this is an excellent option.

ENVIRONMENTAL IMPACT

Lead acid batteries don't impress when it comes to their environmental impact. Lead acid batteries, which provide a similar level of solar energy storage capacity as lithium-ion batteries, require significantly more raw materials. Consequently, a greater carbon footprint is created with more raw materials.

Moreover, the lead-acid industry currently consumes a tremendous amount of energy. Energy is used for even the production of the battery. Pollution is dumped into the environment as a result of this process.

Though lithium-ion batteries derive their materials from mining, the amount of material each battery requires is less, so environmental impacts are minimized. Lithium-ion solar battery  manufacturers are also exploring renewable energy sources as a potential power source, which may result in a significantly smaller carbon footprint.

In a new manufacturing plant that uses renewable energy to run the batteries for storing renewable energy, we would create batteries that can store renewable energy. This is a win-win for all parties involved, isn't it?

And just little bit more in detail,

In comparison with lithium-ion batteries, lead acid batteries are less environmentally friendly. To hold the same amount of energy, lead acid batteries require large quantities of raw material, which has a much larger environmental impact during the mining process. As a result of its heavy use of energy, the lead processing industry also emits large quantities of pollution. The risks associated with lead to humans are negligible due to both the manufacturing method and the battery packaging. There are some environmental problems associated with lithium. Mining for lithium carbonate, copper, aluminium, and iron ore is the main component of a lithium-ion cell. Mineral extraction, specifically lithium mining, is highly resource intensive, but lithium constitutes only a small proportion by mass of a battery, so the environmental impact of aluminium and copper is much greater than that of lithium. Even though lithium-ion recycling is still merely a small industry currently, it has demonstrated high levels of recyclability and recovery, so the industry is predicted to rival lead acid recycling rates soon.

RECYCLING

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Due to the higher recycling rate of lead acid batteries, they are seen as environmentally friendly since they are more eco-friendly than lithium-ion batteries. Even though they're recycled less frequently than lead acid batteries, lithium-ion solar batteries are still very effective and recyclable.

Since lithium-ion batteries are relatively new, and the equipment needed to recycle them is still being developed-making recycling them pricey-the former is more likely to be recycled more frequently than lead acid batteries. Nevertheless, as lithium-ion battery use and recycling grow, lead acid battery recycling will likely catch up to lithium-ion battery recycling in a short period of time. Lithium-ion batteries have the potential to be even more eco-friendly than lead acid battery recycling, thanks to the cost-effective use of recycled lithium compared to mining for new lithium. As the lithium-ion solar battery recycling industry looks set to grow dramatically in the next few years, it's safe to say it'll be an exciting time.

What Should You Choose Among LEAD-ACID versus LITHIUM-ION?

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Lithium-ion batteries are a much higher upfront investment, but the long-term costs are relatively similar between the two types of batteries. We therefore do not recommend their solar energy generation system to those who will not be using it every day.

Using Lithium Ion batteries is becoming an increasingly popular choice due to the significant benefits Lithium Ion technology offers over lead-acid batteries. One needs to pay attention to a couple of factors when deciding to switch from a lead-acid to Lithium Ion battery bank.

Other factors, such as how the system is used and what batteries you need, can also affect what type of batteries you need. Our recommendations for batteries for different applications are as follows:

FULL-TIME OFF-GRID ESTABLISHMENT


We recommend FLA batteries (if you don't mind regular maintenance) for off-grid solar power generation systems, or Lithium-ion batteries for infrastructure that uses them heavily.

OFF-GRID VACATION HOME/CABIN


A few times a year is the most likely frequency of visitation to an off-grid vacation or hunting cabin. In other words, FLA batteries would require significantly more care than you could provide them. The best way to go is to use SLA batteries. Leaving them unused for a few months won't cause them to go flat, and they don't need to be maintained at all.

BATTERY BACKUP SYSTEM


If you build a power generation system with battery storage as a backup system in case of a power outage, you'll be able to generate power. If the power grid in the area is extremely unreliable, you may only be able to use the system once or twice a year. Now, you won't need to invest in lithium-ion batteries since the system is not frequently used.

Another option could be to use FLA batteries. Again, regular maintenance is necessary, and if the system is only used occasionally, this can be a real headache. Thus, the best option would be SLA batteries.

REMOTE INDUSTRIAL USE


There is not much difference in the way decisions are made here. A lithium-ion solar battery can be a wise investment for industrial sites that are used extensively off the grid. As an off-grid outpost, you can use SLA batteries to run rudimentary monitoring equipment. You won't have to schedule regular maintenance visits, and you can save money, too.

SAFETY


The lead acid and the lithium ion batteries can both go into a "thermal runaway," whereby the electrolyte, flames, and poisonous fumes make their way out of the battery. Because the lithium-ion battery has a higher degree of energy density and smaller volume, the probability and consequences of an event are higher. The safety of cells and packs is maintained by taking various precautions for preventing trigger events, such as short circuits and overheating, yet incidents still occur.

The Closing Words


The demand for solar power generation and energy storage solutions will increase as fossil fuel prices rise and emission standards tighten around the globe. Our article has summarized the pros and cons of both solar battery technologies and ultimately it depends on your specific needs and budget to decide which one you prefer.

For any other questions please contact us