What is the difference between a Lithium leisure battery and an AGM battery?
What is the difference between a Lithium leisure battery and an AGM battery?
Wet (flooded) lead-acid
This is old technology now for a leisure battery, it requires the most maintenance.
Maintenance: Requires periodic topping up with de-ionised water to maintain the electrolyte level.
Depth of Discharge (DoD): Should not be regularly discharged below 50% of its total capacity to avoid damage and shorten its lifespan.
Best for: Budget-conscious users who make infrequent, casual trips and are willing to perform regular maintenance.
Absorbed Glass Mat (AGM)
AGM batteries are an advanced type of lead-acid battery where the electrolyte is absorbed into a fiberglass mat. This makes them more durable and safer than traditional wet lead-acid batteries.
Maintenance: Maintenance-free, as the unit is completely sealed and spill-proof.
Depth of Discharge (DoD): Can be safely discharged to around 70% of its capacity, providing more usable power than a wet lead-acid battery.
Charging: Charges faster than traditional wet lead-acid batteries.
Durability: Highly resistant to vibration, making them ideal for mobile applications.
Best for: Frequent travellers who need a balance of good performance, durability, and a medium price point.
Gel
Gel batteries use a gelled electrolyte, which makes them completely sealed and spill-proof. This is particularly useful in applications where the battery might be tipped on its side.
Maintenance: Completely maintenance-free.
Durability: Very robust and can handle deeper discharges than standard lead-acid batteries.
Charging: Requires a specific, lower charging voltage than AGM batteries. Using the wrong charger can cause damage.
Best for: Campervans, mobility scooters, boats.
Lithium (LiFePO4)
Lithium Iron Phosphate (LiFePO4) batteries are the most advanced and highest-performing leisure batteries. They are significantly different from lead-acid technology.
Weight: Weigh about half as much as a comparable AGM or lead-acid battery.
Usable Capacity: Can be safely discharged almost completely (up to 95%), providing far more usable power than other battery types.
Lifespan: Offers a much longer cycle life, lasting for thousands of cycles compared to a few hundred for lead-acid versions.
Charging: Charges much faster and more efficiently. Many come with a built-in Battery Management System (BMS) to ensure safety and longevity.
Has the highest initial cost, but their long lifespan and superior performance can make them more cost-effective over time.
Best for: Serious campers and full-time travellers who need maximum power efficiency, a long lifespan, and are concerned about weight.
Conclusion
If you are looking to upgrade an existing system that has a simple lead acid battery already installed then an AGM battery will be compatible with the charging system that you already have.
If you wanted to upgrade an existing system, again, that has a simple lead acid battery but to a Gel or Lithium battery then you would need to check that your exiting charging system has a Gel or Lithium battery charging profile. You may require an overhaul of the charging system.
You will damage a Gel or Lithium battery if you use the wrong charger.
If you have a blank canvas to start with then a Lithium Iron Phosphate (LiFePO4) leisure battery is by far the best option, charge it up with a good quality DC-DC charger, mains charger and / or a solar MPPT charger. We recommend Victron Energy components for the charging system.