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BRL Electronics

What is the difference between AGM, lithium and sodium batteries?

AGM, lithium and sodium are different battery technologies with different characteristics in terms of weight, capacity, charging and applications.

The most suitable technology depends on what the battery will be used for.

AGM batteries

AGM stands for Absorbent Glass Mat and is a type of lead-acid battery where the electrolyte is held in glass fibre mats.

AGM batteries are used in applications including cars with start/stop systems, vehicles with high electrical loads and certain audio installations.

Advantages:

  • Generally withstand repeated charging cycles better than traditional starter batteries.

  • Have low self-discharge.

  • Are sealed and normally require no maintenance.

  • Can deliver high starting current.



Lithium batteries

Lithium batteries come in several variants, such as LiFePO4 and other lithium-ion chemistries.

They are used, for example, as leisure batteries in motorhomes, boats and customised audio installations.

Advantages:

  • Low weight relative to capacity.

  • Can often deliver high power.

  • Normally have a long cycle life when used correctly.

  • Can offer high usable capacity.

Lithium batteries require appropriate charging conditions and a suitable battery management system (BMS). Not all lithium batteries are intended for use as starter batteries.



Sodium batteries

Sodium batteries, often called sodium-ion batteries, are a newer battery technology that uses sodium ions instead of lithium ions.

The technology has the potential to offer good performance at low temperatures and uses different raw materials from traditional lithium-ion batteries.

However, characteristics vary between manufacturers and battery models.



Which battery is best?
No single battery is best for every application.

AGM is an established option in many vehicles, while lithium and sodium may be of interest for specific installations where weight, cycle life or high current capability is important, for example.

Important: These battery technologies are not automatically interchangeable. Always check compatibility with the vehicle’s charging system and follow the battery manufacturer’s instructions.