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Lead Acid vs Lithium: Which Battery Wins for Solar Power?

Comparison of lead acid and lithium batteries in solar applications

When you're sizing up options to select the right battery for your solar system, you probably have a checklist—what voltage is needed, how much capacity, and whether you need it for daily cycles or standby power. Once you've got that sorted, you might find yourself asking, "Should I opt for a lithium battery or stick with the traditional lead acid?" Or even more critical, "What really sets lithium apart from lead acid?" These are the types of questions that can make or break your decision.

In this piece, we dive into the world of lead-acid and lithium-ion batteries—two of the frontrunners in solar applications. Both types bring their own strengths and challenges to the table, and understanding these can help you make a well-informed choice that suits your specific needs.

In This Article


Lead Acid vs. Lithium Batteries – Overview

At the core, lithium batteries are crafted using the lightweight and highly reactive element lithium, while lead acid batteries are built around the heavier and more stable element lead. Let's dive into the specifics of lead acid and lithium batteries to see which might be the best fit for you.

1. Lead Acid Batteries

Lead acid batteries have been the go-to choice for decades, known for their reliability and lower upfront cost. They come in several types, each with its own set of characteristics:

  • Sealed Lead Acid (SLA): This category includes Gel and Absorbent Glass Mat (AGM) batteries. Both types are spill-proof thanks to their sealed structure, making them a safer option in volatile environments. AGM batteries are particularly robust, offering higher output and quicker charging compared to Gel batteries, which have lower charge rates and output.

  • Flooded Lead Acid (FLA): FLA batteries are the traditional type, where the battery plates are submerged in water. They require regular maintenance, including water top-ups and ensuring they are stored in vented areas to allow gases to escape, which is crucial to prevent damage and ensure safety.

2. Lithium Batteries

On the flip side, lithium batteries are the newer technology on the block, bringing higher efficiency and a longer lifespan to the table:

Lithium Iron Phosphate (LiFePO4): Often considered the gold standard for solar applications, these batteries offer significant advantages over lead acid. They are maintenance-free, do not require venting, and can handle deeper discharge cycles, which translates to longer life and better performance.

Lithium-ion vs. lead acid batteries: who wins?


Lead Acid



$650 - $1,400+

$6,000 - $15,000+


1 - 6 kWh

15+ kWh


80 - 90%

95 - 98%

Depth of Discharge


80 - 90%


5 - 13 years

10 - 20 years

Why Lithium-Ion Batteries Seem to Outshine Others

  1. Compact Power: Their smaller size and higher energy density mean you can pack a lot of power into a little space. .

  2. Efficiency at its Best: With round-trip efficiency rates hitting around 95%, nearly all the energy you store is available for use again. This efficiency minimizes waste and enhances the overall system effectiveness.

  3. Cost-Effective Over Time: Though the initial investment might be higher, the extended cycle life of lithium-ion batteries means they can end up being more economical in the long run. They're designed to last longer, which means fewer replacements and better returns on your investment.

  4. High Performance: Lithium-ion batteries can handle being charged and discharged at high speeds and can operate effectively even when heavily depleted. This flexibility allows you to utilize a smaller battery to achieve the same or better performance as a larger lead acid battery.

How do lithium-ion and lead acid batteries compare?

When deciding between lithium-ion and lead acid batteries for your solar system, there are several key factors to consider. Each type has its unique advantages and drawbacks:

  • Cost: Initially, lead acid batteries may seem like a more budget-friendly option, costing significantly less than lithium-ion batteries. However, the lower upfront cost is offset by shorter lifespans and higher maintenance needs​​.

  • Rate of Charge: Lithium-ion batteries stand out for their quick charge rates, allowing them to take on large currents swiftly. For instance, a lithium battery with a 450 amp-hour capacity charged at a C/6 rate would absorb 75 amps. This rapid recharge capability is vital for solar systems, where quick energy storage is essential. In contrast, lead acid batteries are limited in how fast they can be charged. They overheat if charged too quickly and their acceptance rate declines as they approach full capacity. At about 85% capacity, the charging must slow down to prevent damage, making the overall charging process longer—often more than twice as long as lithium-ion batteries.

  • Depth of Discharge: Lithium-ion batteries allow for a deeper discharge without significant damage, typically up to 85% or more of their capacity. Lead acid batteries, however, should generally not be discharged beyond 50% to avoid affecting their lifespan adversely​​.

  • Energy Density: Lithium-ion batteries store more energy in less space due to their higher energy density. This means you can use fewer lithium batteries to achieve the same storage capacity as a larger number of lead acid batteries, which can be crucial in space-constrained installations.

  • Efficiency: Lithium-ion batteries boast efficiencies of 95% or greater, meaning that most of the energy stored is actually usable. Lead acid batteries typically have efficiencies between 80% to 85%, leading to greater energy loss during storage and retrieval​​.

  • Maintenance: Lead acid batteries require regular maintenance, including checking water levels and cleaning terminals to ensure optimal performance. Lithium-ion batteries, on the other hand, are virtually maintenance-free, which reduces ongoing care efforts and costs​.

  • Lifespan: Lithium-ion batteries generally last longer than lead acid, handling more charge cycles before their performance degrades. This longer lifespan can translate into better long-term value despite the higher initial cost​.

  • Recyclability: Currently, lead acid batteries are recycled at a higher rate than lithium-ion. However, as recycling technologies improve and become more widely available, lithium-ion battery recycling is expected to increase and potentially surpass lead acid in terms of environmental friendliness​.

How Lead Acid and Lithium Batteries Perform in the Cold

Lead Acid and Lithium Batteries Performance in the Cold

Dealing with cold weather? You’ll find that both lead acid and lithium batteries face challenges, but in different ways. Temperature drops affect battery performance across the board, reducing their capacity to hold and deliver power.

Charging in Cold Conditions: Lithium batteries typically struggle with charging when the temperature dips below 0 degrees Celsius (32 degrees Fahrenheit). They just don’t accept a charge well under freezing conditions, which could be a hurdle in colder climates. On the flip side, lead acid batteries can still accept a charge in these lower temperatures, although their overall efficiency is reduced.

Discharge Performance: When it comes to using the stored energy, lithium batteries have the upper hand in cold weather. Even at 0 degrees Celsius, lithium batteries can discharge about 70% of their capacity effectively. Lead acid batteries, however, only manage about 45% under similar conditions. This means lithium batteries provide more usable energy in the cold without needing to be oversized.

Battery Condition and Charging: There's an interesting twist with lithium batteries—if you've just used the battery and it’s still warm from discharge, you might manage to charge it even in colder temperatures. But, if it’s cooled down significantly, charging could be challenging.

So, when planning your solar system or other applications where cold weather is a factor, consider how each battery type might perform. Lithium batteries offer better discharge capabilities in the cold, although charging them can be tricky. Lead acid batteries are more forgiving when it comes to charging in low temperatures, but they don’t offer as much discharge capacity.

Our Thoughts

When it comes to choosing between lead acid and lithium batteries for your solar setup, the best answer isn't always straightforward—it depends on your specific needs and circumstances. If you're setting up a solar system for a rarely used RV or boat, a lead acid battery might suffice due to its lower cost and acceptable performance under infrequent use. This can be a smart choice that balances cost against utility, mitigating some of the drawbacks like shorter lifespan and lower discharge depth associated with lead acid batteries. And the cool part is – there is nothing stopping you from trying out the two together, experimenting to see how they complement each other in your solar setup.

Not sure which battery fits best with your solar system's needs? Contact us today! We’ll help you navigate through the options to find the perfect solution tailored to your setup. Whether you’re looking for portable solar panels, generators, or complete solar kits, we have the expertise and products to power your lifestyle. Reach out now and take a step towards efficient and reliable solar energy.


Why lithium over lead-acid?

Lithium batteries offer higher energy density, greater efficiency, and longer lifespans compared to lead-acid batteries. They are more compact, lighter, and typically have a deeper discharge capability without significant degradation, making them ideal for high-demand applications and reducing long-term replacement and maintenance costs.

Can I just replace a lead-acid battery with lithium?

Replacing a lead-acid battery with a lithium one isn't a straightforward swap due to differences in voltage and charging profiles. It often requires a compatible charger and a battery management system to ensure safety and efficiency. Additionally, the electrical system may need adjustments to handle the different characteristics of lithium batteries.

What are the disadvantages of lithium-ion batteries?

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