is a Sealed Lead Acid Battery?
The sealed lead acid battery is by far one of the most popular
batteries that we receive questions on here at High-Tech Battery. I
have decided (finally) to post a few of the most common questions that
I hear from customers regarding sealed lead acid batteries here in our
Battery Information Center, so here it goes.
What exactly is a sealed lead acid
lead acid battery is what is originally known as a VRLA battery, or
a valve regulated lead acid battery. These batteries are a 100%
rechargeable, and based off a lead acid design. These batteries are
designed to be maintenance free (do not require the user to add water
to the cells), and spill proof. These batteries can be mounted in any
position and still operate to their full capacity without spilling a
drop of acid.
You may be wondering where exactly the valve regulated part of the
sealed lead acid battery comes into play. Every SLA (sealed lead acid)
battery is designed with a special safety release valve. These valves
act as a emergency pressure release system that activate to alleviate
the build up of gases within the SLA battery. During a period of an
extremely high rate of charge (extreme over-charging), gases will be
generated inside the battery that could potentially build up to
critical levels and force its way out - via exploding a side of the
battery out, or a simple crack in one of the cell dividers. To prevent
this from happening, all SLA batteries are designed with these small
pressure release valves.
Are there different types of sealed
lead acid batteries?
Yes, there are two different types of SLA batteries out on the market
today - AGM, and GEL batteries.
AGM batteries utilize a special plating process which optimizes the
effectiveness of electrolyte reaching the batteries lead plates. AGM
stands for absorbed glass mat, which is essentially what the entire
process consists of. A mat consisting of very thin glass fibers woven
together is placed between the internal lead plates of the battery.
This glass mat is capable of absorbing and holding the optimum amount
of electrolyte between the plates for the lifetime of the battery. This
technology cuts down on the use of electrolyte and increases the
efficiency and power of the battery.
The infamous GEL battery (confused with AGM SLA batteries on a daily
basis) utilize a special gel based mixture between the plates of the
battery instead of the typical electrolyte found in the common flooded
lead acid batteries (think car battery). In this case, the gel is a
combination of silica fume and standard sulfuric acid to create a type
of gelified electrolyte. This design enables the battery to suffer much
less internal corrosion, thus increasing the overall life of the
battery - assuming you take care of it properly