Key Differences Between Lifepo4 Battery and AGM Battery

Batteries are some of the most widely used devices in the world today. Currently, lithium-ion and lead-acid batteries are the two most prevalent types, with Lifepo4 Battery (Lithium Iron Phosphate Battery) and AGM (Absorbent Glass Mat) battery being well-known for their energy storage capabilities. Despite both being popular for energy storage, these two types of batteries have significant differences due to their distinct materials and properties.

What are Lifepo4 Battery and AGM Battery?

Lifepo4 Battery

An Lifepo4 battery, or Lithium Iron Phosphate battery, is a type of lithium-ion battery that uses lithium iron phosphate for the positive electrode and carbon for the negative electrode. Its nominal voltage is 3.2V. One of its most reassuring features is its excellent safety performance, which is why many manufacturers favor Lifepo4 battery.

AGM Battery

An AGM battery is a type of valve-regulated sealed lead-acid battery that uses a glass fiber separator. Its positive and negative electrodes are made of lead and lead oxides, and it uses sulfuric acid as the electrolyte. The nominal voltage is 2.0V. AGM batteries have a long history and are among the most widely used batteries globally.

Differences Between Lifepo4 and AGM Battery

1. Weight and Volume

Lifepo4 battery is generally less than half the weight of AGM battery and is also smaller in size. For the same capacity, the size and appearance difference between these two batteries is substantial.

2. Energy Density

Lifepo4 battery typically have an energy density of 90-160 Wh/kg, with high-quality versions reaching 180-210 Wh/kg. AGM battery, on the other hand, have an energy density of 50-70 Wh/kg. This means Lifepo4 battery can provide more energy while occupying less space.

3. Available Capacity

The recommended Depth of Discharge (DoD) for LFP battery is 80%, whereas for AGM battery, it's about 50%. To achieve the same energy output, more AGM battery may be needed compared to Lifepo4 battery.

4. Service Life and Cycle Time

Under normal use, LFP batteries can last over 10 years with 3000-7000 cycles. In contrast, AGM battery typically last 3-5 years with 1000-1200 cycles.

5. Charge and Discharge Efficiency

LFP batteries charge much faster than AGM battery. An Lifepo4 battery can be fully charged in about 5 hours, while an AGM battery may take more than 10 hours. Lifepo4 battery support higher discharge rates (1C) compared to AGM battery (0.5C), making them more efficient in high-demand scenarios.

6. Temperature

Lifepo4 batteries are highly resistant to high temperatures but perform poorly in low temperatures and generally cannot be charged below 0°C. AGM batteries, however, have a broader operating temperature range and can be charged at low temperatures.

7. Safety

Lifepo4 battery is extremely safe, thanks to their chemistry and manufacturing. They do not explode even if subjected to severe abuse, such as being thrown from a height, squeezed, or punctured. AGM battery, with their sulfuric acid electrolyte, pose a greater danger in case of leakage.

8. Environmental Impact

Lifepo4 battery use more environmentally friendly materials and have less impact on the environment. AGM battery contain lead, a toxic heavy metal. Both types of batteries should be disposed of properly to minimize environmental harm.

9. Self-Discharge Rate

Lifepo4 battery have a self-discharge rate of 2-3% per month, whereas AGM battery have a rate of 4-6% per month (with other lead-acid batteries potentially reaching 20%). This means lifepo4 battery can be stored longer without needing frequent recharging. AGM battery should be stored at 100% State of Charge (SOC), while lifepo4 battery only need 50%.

10. Price

LFP batteries are more expensive upfront, costing more than three times the price of AGM batteries. However, over a lifespan of more than five years, LFP batteries can be more cost-effective and provide better overall performance, life, and safety.

Which is Better?

Both Lifepo4 battery and AGM battery have their merits, and the choice largely depends on your budget. If you have a higher budget, Lifepo4 batteries are the superior choice due to their longer lifespan, better performance, and safety. If you are on a tighter budget, AGM batteries are still a good option. However, generally speaking, Lifepo4 battery is recommended for their overall benefits and ability to replace almost any lead-acid battery, making them a valuable upgrade.