VRLA – Valve Regulated Lead Acid
Valve Regulated Lead Acid batteries are sealed lead-acid.
They include Absorbed Glass Mat (AGM) and gelled electrolyte (GEL) type, both of which have the following characteristics:
- Sealed using special pressure valves and should never be opened. Non-spillable , and therefore can be operated in virtually any position (except upside down).
- Is completely maintenance–free, does not need topping in service life.
- All of the electrolyte is immobilized (absorbed in AGM or fixed in Gel structure).
- Uses recombination reaction to prevent the escape of hydrogen and oxygen gases which are normally lost in flooded lead–acid batteries.
- Non-spillable , and therefore can be operated in virtually any position (except upside down).
GEL – In addition to the characteristics of VRLA, GEL batteries:
- Use thixotropic gelled electrolyte, it is in a solid state between the plates and separators.
- Unlike traditional AGM electrolyte "starve" designs, GEL batteries have 15 – 25% more electrolyte volume than AGM type.
- Utilize different separator material such as PE, PVC, etc.
Differences between GEL batteries and AGM batteries:
- Both are sealed recombinant batteries. Both are sealed valve-regulated lead-acid (VRLA). AGM batteries and GEL batteries are both considered “acid-starved” and the electrolyte does not flow like a normal liquid.
- The gel electrolyte has the consistency and appearance of petroleum jelly. Like gelled electrolyte batteries, AGM batteries are also considered non-spillable as all of the liquid electrolyte is trapped in the sponge–like matted glass fiber separator material.
- Due to the physical properties of the gelled electrolyte, gel batteries have higher internal resistance.
- AGM batteries have excellent performance for high current/power discharge and GEL excels in higher/lower temperature stability and lower current/power discharge applications.
- AGM batteries have higher specific energy density than GEL batteries, but GEL batteries have longer service life.
