Why does VRLA battery bulge?

Sealed lead acid batteries (VRLA) typically used in UPS can swell as they are manufactured in such a way to allow absorption of gasses released during the chemical process inside the battery.In other words, the gases caused by the chemical reaction taking place inside the battery due to age or chemical breakdown and …

What causes a lead acid battery to swell?

A battery becomes swollen as a result of overcharging. Excessive current will flow into the battery after the battery has reached a full charge. The constant current will cause decomposition of the water in the electrolyte and premature aging. At high rates of overcharge a battery will progressively heat up.

What would cause a battery to bulge?

Swollen batteries, while not common, are a significant risk. They are the result of too much current inside a cell of the battery, which causes a build-up of heat and gas. This can be caused by overcharging, manufacturer defect, deep discharge, or damage to the battery.

Do VRLA batteries require ventilation?

In terms of Hydrogen accumulation, VRLA batteries do not vent unless they are forced into failure mode. The IFC requires continuous ventilation that will handle the unlikely event of an excessively gassing battery, no matter what type it is.

Can VRLA batteries explode?

Our VRLA batteries contain high density energy. Incorrect operation can cause explosion, leaking acid, as well as extreme heat. Placing the battery in an hermetically sealed space can cause the battery to explode causing damage to the machinery or extreme personal injury.

What are VRLA batteries used for?

VRLA batteries are used extensively in power wheelchairs, as the extremely low gas and acid output makes them much safer for indoor use. VRLA batteries are also used in the uninterruptible power supply (UPS) as a backup when the electrical power goes off.

Can VRLA battery be charged?

Charging methods used for VRLA batteries have largely been similar or identical to those developed for flooded lead-acid batteries. Constant-current (CC) charging is also a viable approach for VRLA products, particularly in multi-cell strings — and the longer the string, the more it is appropriate.

How do you store swollen batteries?

You want to store it for as short a time as possible. For the most part, unless you stab it, an unused bloated battery ought to be reasonably safe. On a practical note, you want to leave it somewhere cool and dry, so a refrigerator is not the best place.

Do VRLA batteries off gas?

The volume of gas emitted by the VRLA battery is very small under normal float and equalization charging conditions and special mechanical ventilation would not normally be required. Hydrogen is lighter than air and disperses quickly throughout the surrounding atmosphere.

Overcharging or short-circuiting of the battery is the only reason for swelling up of the lead acid battery. The problem is not inherent in the battery itself. In order to avoid swelling up of the battery you need to tackle the underlying cause of the problem.

How do you reduce the gas emitted from VRLA batteries?

Critical to minimizing the gas emitted from the VRLA battery is the use of the proper float charging voltage of between 2.25 and 2.3 volts per cell and limited use of the equalization voltage of 2.4 volts per cell. As the charging voltage per cell is increased above 2.3 volts per cell the gassing rate increases dramatically.

How to prevent the battery from getting swollen up and expanding?

The lower storage voltage reduces corrosion of the positive plates. Once every week the charge voltage is increased to the absorption level for a short period to compensate for self discharge (Battery Refresh mode) The above tips will help you to prevent your battery from getting swollen up and expanding.

What is the float voltage of a VRLA battery?

However, this rate could increase by a factor of 20 or more at 2.5 volts per cell. For this reason, the VRLA battery float voltage should be limited to the recommended range of 2.25 to 2.30 volts per cell average at 77 degrees F, and the equalization voltage should be limited to 2.4 volts per cell.