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Valve Regulated Lead Acid – Euro Energy Guide to Battery Chemistries number 2

Valve Regulated Lead Acid batteries (Often known as VRLA, Sealed Lead Acid, SLA or AGM) were first brought to market during the 1950s, but can still offer the ideal solution to power many products.

The technology used in lead acid batteries matured many years ago creating a robust, low cost battery, readily available globally from multiple manufacturers.

Their operation allows 99% of all gas produced to be recombined during normal use, so the need for regular topping up is removed and allowing them to be classified as ‘Non-Spillable’.

Anyone who ships batteries will know this classification greatly simplifies the delivery process.

Key to the design of lead acid batteries are glass fibre separators which sit between the lead calcium grids.

These hold the acid in suspension, so even if stored upside down they won’t leak!

This is coupled with a low- pressure relief valve, effectively a rubber cap over the filler spout, which keeps the acid in.

In the event of an incident such as over-charging, this will slowly allow the gas to release and disperse to atmosphere. So long as the enclosure is adequately ventilated, sufficiently to prevent a 4% concentration, they remain completely safe.

Some manufacturers are so confident in their lead acid batteries they approve operation in any orientation, including upside down!

The ‘block’ format of VRLA batteries also make them ideal to build into bespoke battery packs in either series or parallel battery pack configurations.

Here are a few of the batteries that we build here at Euro Energy that use lead acid batteries, demonstrating versatility of VRLA;

Euro Energy Guide to Battery Chemistries number 2 – Valve Regulated Lead Acid

Euro Energy Guide to Battery Chemistries number 2 – Valve Regulated Lead Acid

Euro Energy Guide to Battery Chemistries number 2 – Valve Regulated Lead Acid

The cycle life and operational time of lead acid batteries are heavily dependent on the way in which the battery is used and maintained.

Regular deep cycling will soon reduce capacity, as will high temperature operation (as the result of high ambient temperatures or aggressive charging regimes for example).

Storing after a full discharge without recharging is also bad for your battery.

This may cause ‘Sulphation’, where lead sulphate crystals begin to form within the battery which then act to prevent recharging and normal battery operation.

How to Keep your Lead Acid Battery Healthy

  • Always recharge after use, store fully charged
  • Recharge at least every 6 months if stored
  • Keep the battery in a cool place, cooler the better
  • Use a good quality charger – make sure it’s 3 stage charger if the battery is used in a cyclic application
  • Charge only at room temperature
  • If the battery will be used in a very hot or very cold location, consider reducing or increasing charge voltage in line with the manufacturer’s recommendations

And finally, always make sure the battery specified is the correct type for the intended use.

For example, a general purpose battery in a cyclic application will have a very short life.

Read our blog about the differences between cyclic & standby batteries here.

Here at Euro Energy, we stock a comprehensive range of Sealed Lead Acid batteries to ensure that most batteries are available for immediate despatch and our intelligent stock management system ensures that our lead acid batteries are in perfect condition when they leave our shelves!

We stock batteries from Cyclon, Fiamm, MK, Panasonic, PBQ, Powersonic, Sonnenschein and Yuasa. You can read more about our range of Sealed Lead Acid batteries here.

For further information on Sealed Lead Acid/Valve Regulated Lead Acid (SLA/VRLA) batteries and battery packs or to learn more about our custom battery pack design and build service, contact our friendly & knowledgeable Customer Service team on 0116 2340567 or email