Technology is such a topic of discussion that one can spend days talking about the way it has touched our lives and the speed at which it has changed. When we factor in automotive technologies, the discussion is bound to go on. However, one of the things that stand the risk of being ignored is car battery. So many changes have taken place inside a car’s battery while its outer appearance has stayed the same. This has led everyone to think that batteries may be among the most primitive of things in a car. However, nothing can be further from the truth. To explain the changes, we bring you the types of car batteries (by design),that are available in mass-market cars today:
Flooded Lead Acid
Batteries have always been central to a car’s functioning. However, since most folks do not look under their car’s hood just for the sake of it, the knowledge regarding the sealed lead acid type battery has been limited. A typical battery has six cells arranged in a series circuit. Each cell produces 2 volts, with total output going up to 12 volts. Here comes the change â€“a flooded lead acid type battery contains electrolyte (Sulphuric Acid) in liquid form, making it unsuitable for many portable applications. Water levels also need to be maintained in the cells. An advantage of all this is that peak power output of flooded batteries is higher than those of other types.
Valve-regulated Lead Acid
Valve Regulated Lead Acid (VRLA) batteries are also called maintenance-free batteries. Now, car batteries are supposed to get discharged and then recharged. However, if the charging current is more than requiredÂ during recharge cycle, some current is wasted in decomposing water in the cells to hydrogen and oxygen. A flooded lead acid battery, due to its design, releases these gasses, thereby needing water top-up. A VRLA battery, on the other hand, retains these gases as long as the pressure remains within safe levels. These gases can either recombine with each other, with or without the help of a catalyst. However, if the pressure exceeds prescribed limit, safety valves of the battery open up to release the gasses. A downside to all this is that in case water levels drops in cells, it cannot be topped off, as in the case of flooded lead acid batteries, even if they are flooded-type VRLA batteries. These batteries are more suited to applications where charge/recharge cycles are slow, like power storage applications.
Why they are used in cars?
This is simple – unlike flooded batteries where electrolyte always moves around, in VRLA batteries, it is kept immobilised by using either fibreglass mats or by using silica and gelling agents to turn it into a paste-like gel. This leads to classification of VRLA batteries as Glass-mat batteries and Gel batteries (we have already mentioned Flooded VRLA battery type above).
Differences between the two types
There are a few important differences between Flooded Lead Acid and VRLA batteries. Here are those differences:
- Both Glass-mat and Gel batteries have shorter recharge cycles than flooded lead acid type. This is because calcium is added to their plates to reduce water loss.
- While neither battery type can tolerate overcharging, the Flooded Lead Acid batteries can stand the abuse more than either Glass-mat or Gel batteries. In the case of Glass-mat or Gel batteries, overcharging can lead to premature failure much earlier than flooded lead acid type.
- The lifespan, given everything is maintained properly, is shorter for Glass-mat and Gel batteries, as compared to Flooded Lead Acid type.
- Glass-mat and Gel batteries discharge less hydrogen than flooded lead acid type, which we have earlier talked about.
- As opposed to flooded lead acid batteries, both glass-mat and gel batteries can be used and positioned in any orientation of user’s choice. This is the primary reason why they are preferred for use inÂ automobiles.