Lead Acid vs. Lithium Batteries – Which One Utilize the Better Technology

With so many battery types available, the debate about lead acid vs lithium ion batteries continues.

Users want a reliable battery that gives them value for their money, with optimal power and performance. Two of the most sought-after battery types are lead-acid and lithium-ion (Li-Ion) batteries.

In this article, we will discuss the difference between these two types. You will learn about the performance of lead-acid vs lithium-ion batteries based on specific parameters.

How Does the Technology of Lithium-Ion Batteries and Lead Acid Batteries Differ?

A lithium-ion battery and lead-acid battery work using entirely different technology. Let’s examine each battery’s chemistry and the different types of each battery.

Lead Acid Batteries

These typically consist of a positive electrode (Lead Oxide) and a negative electrode (Porous Lead) dipped in an acidic solution of diluted sulphuric acid.

When discharging, the lead on each electrode breaks down to provide the electric current that flows through the electrolytes. During charging, lead forms on the electrodes.

Lead-acid batteries have vast applications, and several different types have been developed. Here are some of the most popular ones:

Flooded Lead Acid Batteries (FLA)

FLA models contain a liquid electrolyte that freely moves around the battery case. You have to keep them upright, or the electrolyte will leak out.

These are the cheapest batteries on the market and require high maintenance for long life.

Sealed Lead Acid Batteries (SLA)

Sealed lead-acid batteries are also known as valve-regulated lead-acid batteries (VRLA). The electrolyte is in a sealed container that contains a valve to release the gaseous buildup inside the battery system.

Two types of sealed lead-acid batteries are common:

Absorbent Glass Mat (AGM)

A glass fibre mat separates the electrodes in an AGM battery. The mat absorbs the electrolyte solution. There is sufficient electrolyte to wet the glass mat but not enough to leak out during a puncture.

Gel

In the case of gel batteries, the liquid electrolyte is replaced by an electrolyte gel. This silica-based gel has the consistency of a paste, which eliminates the possibility of leakage and significantly reduces evaporation.

Lithium (Li-Ion) Batteries

In lithium batteries, the movement of lithium ions between the positive and negative electrodes generates electricity. A lithium battery does not require a liquid electrolyte, which gives them a tremendous boost compared to lead-acid batteries.

There are many types of lithium batteries. They vary in size, application, and construction. The new technology in lithium batteries is Lithium Ferrous Phosphate (LiFePO4 or LFP). It is the best battery technology today.

How Do Lithium-Ion Battery and Lead Acid Battery Compare?

To have a clear idea about the difference in the performance of a lithium battery and a lead-acid battery, let’s evaluate them based on several factors that matter:

Depth of Discharge (DoD)

This is the percentage of the fully charged state to which a battery can be safely discharged, without harming it. In other words, how much energy stored can be used. A higher depth of discharge means you can use more energy stored in the battery.

Lead Acid Batteries

• In the case of a lead-acid battery, the depth of discharge is only about 50%. Once you have used half the battery capacity, you must recharge it, which significantly limits the battery performance and range.

Lithium Batteries

• For lithium batteries, the depth of discharge is 95% or more. If you invest in a high-quality lithium battery using LFP technology, the depth of discharge increases to 98%.

Winner: WIthout hesitation, lithium, especially the LFP batteries, offer the best depth of discharge.

Cycle Life and Lifespan

The cycle life is the number of charge cycles a battery can go through without a reduction in performance. One single cycle occurs once a battery discharges because of powering appliances and is then recharged.

A battery with a longer cycle life will last longer than one with a shorter cycle life.

Lead Acid Batteries

• For a lead-acid battery, you can expect a cycle life of about 300 cycles. Typically, you can expect a lead-acid battery to last about one to two years.

Lithium Batteries

• Lithium batteries are well known for their long lifespan. Eco Tree Lithium’s LFP batteries take this performance even further, providing a cycle life of about 5000 cycles. In terms of years, these LFP batteries can last upwards of 10 years.

Winner: Lithium batteries have a better lifespan than lead-acid batteries, typically lasting about six to ten times longer.

Self Discharge Rate (SDR)

This is the rate at which a battery discharges when not connected to any electrical load. This phenomenon occurs due to internal battery chemistries. A low SDR indicates a better-performing battery.

Lead Acid Batteries

• Lead-acid batteries typically have an SDR of about 4% per week. You must regularly check to ensure the battery has not discharged during storage.

Lithium Batteries

• The SDR for a lithium-ion battery is very low, about 1-2% per month. It means that it retains almost all the charge regardless of how long you store it.

Winner: Lithium-ion options are better than lead-acid batteries in terms of self-discharge rate, as lithium-ion batteries self-discharge ten times slower than lead-acid batteries.

Size and Weight

The size and weight of the battery are important factors for mobile applications such as electric vehicles, cycles, and motorhomes. Users prefer smaller, lightweight batteries that require minimum space.

Lead Acid Batteries

• Lead-acid batteries contain significant amounts of lead, a high-density heavyweight material. Additionally, the liquid electrolytes further add to the weight of the battery. On average, a 3 KWh lead-acid battery weighs around 30 kg.

Lithium-ion Batteries

• Lithium is 55% lighter than lead. You can expect a 3 KWh lithium battery to weigh about 6 kg. Lithium-ion batteries also have a greater energy density. So they don’t need the same physical space as conventional lead-acid batteries.

Winner: Lithium-ion technology is a better option if you want a lightweight and compact battery solution. Lead-acid batteries weigh 5 times more than lithium batteries.

Energy Density

Energy density is the amount of energy the battery stores in ratio to its size and weight. A battery with a higher energy density is better since it supplies more energy per unit mass.

Energy density is closely related to embodied energy, or the energy consumed to create the battery.

• Lead-acid batteries have one of the lowest energy density ratings since they are huge but provide the least power. Additionally, with a 50% depth of discharge, they only supply half of their rated battery capacity.
• Even a small lithium battery can supply significantly more energy than a lead-acid battery. Additionally, with a higher depth of discharge, almost the entire battery capacity is available for use.

Winner: Lithium-ion batteries have a very high energy density, and lead-acid batteries are the worst in this regard.

Charging Efficiency

Efficiency relates to how much input charging current is converted into energy stored in the battery. In some cases, much of the input power is wasted in many internal processes, leading to lower efficiency.

Lower efficiency is unsuitable for many applications, such as solar panels, where people want maximum energy storage in their battery backup system.

Lead Acid Batteries

• Lead-acid batteries have an efficiency of about 85%. That means that 15% of the current supplied to the battery is lost.

Lithium-Ion Batteries

• Lithium-ion batteries have an efficiency of 100%. All the energy supplied to the battery is stored and ready for use. Therefore, lithium-ion batteries are ideal for applications such as solar system storage.

Winner: The lithium-ion battery system is 15% more efficient than the lead-acid battery system.

Initial Cost

The initial cost refers to the upfront expense required to purchase a battery. When talking about cost here, we aren’t talking about cost over the lifetime or cost per kWh, just the price of a new battery.

Lead-Acid Batteries

• The initial cost is the only factor that keeps lead-acid battery systems popular on the market today. They are the cheapest option and cost about $65-$100 per kWh.

Lithium-Ion Batteries

• For Lithium-ion batteries, the initial cost tends to be higher. They can cost from $150 to $300 per kWh.

Winner: Lead-acid battery systems have the leading edge when we talk about the purchase cost of a battery. How cost-effective they are over a long time is another story.

Cost Over Their Lifespan

So to get a better idea about the real value for money when purchasing a battery, let’s consider the cost over its entire lifespan. That gives a clearer picture of the cheaper battery system to own.

Lead Acid Batteries

• While you can buy good quality 2 KWh lead-acid battery systems for about $150, they have a shorter lifespan of about 2 years. Not to forget, this battery has a depth of discharge of 50%, so you would be able to optimise only 1 KWh of power during any charge cycle.

Lithium Batteries

• In the case of a lithium battery, a 1 kWh battery costs about $200. A 1KWh lithium battery will provide the same performance as a 2 KWh lead-acid battery since the depth of discharge of a lithium battery is about 98%. Additionally, a lithium battery will last you for about 10 years.

Winner: Li-ion batteries are considerably more cost-effective. Yes, they have a slightly higher initial cost, but you get a battery that lasts six times longer.

Charge Time

Charge time refers to how long it takes a battery to recharge 100% when discharged. Users prefer a shorter charge time as it leads to better operational availability of battery systems.

Lead-Acid batteries

• A lead-acid battery typically requires about 8 hours to fully charge. For this reason, owners generally leave their battery systems charging overnight.

Lithium-Ion Batteries

• With sufficient charging current, a lithium-ion battery can go from discharged to charged in about 150 minutes. Their faster-charging speed makes them available for operation throughout the day.

Winner: Lithium-ion batteries are ahead in terms of charging time as their lead-acid counterparts take three to four times longer to charge.

Safety

Many applications place the battery close to people, such as in motorhomes where people sleep near them. Therefore, battery safety features are an important factor to evaluate.

Lead Acid Batteries

• For a flooded lead-acid battery (FLA), it is vital to keep it upright, or the toxic acidic electrolyte may leak out. A leak can lead to damage to property. With a sealed lead acid battery (SLA), you must ensure adequate ventilation to prevent gas buildup.
• These batteries release hydrogen gas that is highly toxic and flammable. Improper ventilation can cause human poisoning or even explosions of the battery.

Lithium-Ion Batteries

• In the case of lithium-ion batteries, there are no safety precautions that you need to take. Once installed, the battery is safe, and you can forget about it. In the case of Eco Tree Lithium’s LFP batteries, there are extra security measures such as a fire-resistant casing.

Maintenance

Most owners will agree that battery maintenance is one of the most tiresome hassles. More and more people are looking for maintenance-free battery options. So we should examine these two battery technologies in terms of the maintenance required.

Lead Acid Batteries

• FLA batteries require the most maintenance, such as regular topping up of electrolyte fluid and ensuring the battery is always upright. SLA batteries are often advertised as maintenance-free, but is it true?
• In the case of a sealed lead acid battery, you need to monitor the charging cycle to ensure the battery does not become overcharged, or it will be permanently damaged. Additionally, regular ventilation checks are required.

Lithium-Ion Batteries

• A lithium-ion battery is maintenance-free. There are no concerns about venting or electrolyte top-ups. Additionally, the newest models from Eco Tree Lithium LFP are so advanced that they have an inbuilt battery management system (BMS).
• A BMS protects the battery against being overcharged. Once the battery becomes fully charged, the BMS automatically stops the charging cycle. The BMS also monitors the operating temperature of the battery to ensure safety.

Environmental Impact

Your battery isn’t going to last forever. At some point in its lifetime, it will need to be replaced. This factor brings an important question concerning the environmental impact of the battery.

Lead Acid Batteries

• The two main components of a lead-acid battery, the lead plates and the acid, are both highly toxic. They can degrade the environment tremendously, and many additional costs are incurred to ensure they are disposed of safely.
• Also, a lead-acid battery releases very toxic gases into the atmosphere during its lifetime.

Lithium Batteries

• This type of battery is environmentally friendly. Its long battery life means that you will replace it less often. Additionally, using Phosphate in LiFePO4 variants has eliminated the toxic materials used in manufacturing them.

Winner: If you support the go-green initiative, lithium-ion batteries should be your choice.

Warranty

The warranty of a battery indicates the manufacturer’s faith in the battery life. With a longer warranty, you can expect an extended battery lifetime. Let’s compare the typical warranties available for both battery types:

Lead Acid Batteries

• For a lead-acid battery, the most common warranty period is 1 year. Certain manufacturers mention a ‘1+1 year warranty’ with their lead-acid battery models, which is simply a marketing gimmick and does not mean it has a 2-year warranty.

Lithium-ion Batteries

• Most lithium-ion batteries come with a warranty period of 5 years. Eco Tree Lithium batteries provide a written warranty of 6 years due to higher quality products and their longer lifespan.

Winner: Since a battery is expensive, having a written warranty for a specific time helps. Lithium-ion models win again, offering warranties for longer periods, such as five to six times longer than a lead-acid battery.

Lead-Acid vs Lithium-ion Battery – Application Comparison

Here are some applications where people might choose between these two battery technologies. We will mention which battery is ideal for the situation, along with the reasons why.

Solar Applications

More and more people are choosing to install solar panels in residential and commercial premises. For storing the power generated by solar panels and using it later, you require a high-capacity battery or battery bank containing multiple battery units.

For this purpose, lithium-ion batteries are the best choice, as previously mentioned. They have higher efficiency and handle deep discharges, meaning they can charge faster, store more energy, and provide that energy for far longer than an equivalent lead-acid battery.

Leisure Batteries

In leisure vehicles, such as motorhomes or caravans, owners want a battery that can power their appliances. Additionally, safety and maintenance are important factors.

Again, lithium-ion leisure batteries are a better choice since they provide far superior performance with much safer operation.

UPS Batteries

In the case of a UPS (Uninterrupted Power Supply), you want a reliable battery backup system available when required. Both lithium and lead-acid batteries can work as a UPS. However, lithium batteries are the cheaper option considering the lifespan savings.

Electric Vehicles

The preferred battery for an electric vehicle should have better performance and lighter weight. That’s why lithium-ion batteries dominate the EV market without even close competition from any other alternative. It can supply constant power over the entire discharge cycle.

The Verdict

Regardless of which way you look at it, lithium-ion batteries are leaps and bounds ahead of lead-acid batteries. Today, the debate of lead-acid vs lithium-ion is somewhat redundant since a lithium-ion battery is the best option overall.

Final Thoughts – Lithium Battery vs Lead Acid

When choosing a lithium ion battery vs lead acid battery, most users are replacing their traditional lead-acid batteries with better lithium alternatives such as Eco Tree Lithium’s LiFePO4 batteries. Especially for the applications previously mentioned.

Whether considering a battery’s capacity, battery efficiency, or battery life, LFP batteries are better than any other option. And as a cherry on top, the inbuilt BMS ensures long-lasting peace of mind.

FAQs

1. Which is better, a lead-acid vs lithium-ion battery?

A lithium battery is the better choice regardless of what parameters you consider when comparing lead acid vs lithium.

2. Can I replace a lead acid battery with lithium-ion?

Yes. It is safe and easy to replace your current lead acid battery with a lithium-ion battery.

3. How much longer do lithium batteries last than lead acid?

A lithium-ion battery typically lasts about six to ten times longer than a lead acid battery.