Lead/acid “gel” battery technology dates back to the 1950s when it was invented in Germany at the Sonnenschein company.
The electrolyte is frozen by the addition of silica gel. In some batteries, phosphoric acid is added to improve life in deep cycling.
Cracks are created during the first cycles through the gelled electrolyte between the positive and negative electrodes. This facilitates recombination by promoting the transport of gases.
Advantages of Gel batteries
Gel batteries are sealed batteries: no maintenance, no addition of distilled water. Reinforced safety compared to open lead batteries.
“Gel” batteries are well suited for deep discharges and are used in tubular batteries. Because the gelled electrolyte eliminates electrolyte stratification. Which is one of the main causes of the loss of open tubular batteries.
A gel battery can withstand 100% discharge and regains its rated capacity if the discharged holding time is short.
Good to very good cycle life. The best gel batteries such as the 12 V Solar Block batteries reach 2500 cycles at 50% discharge. For example a lifespan of 6 -10 years in solar applications.
Service life > 10 years for 2V tubular gel batteries.
The internal resistance of this type of battery is relatively high. And therefore they do not support the high charging and discharging speed. The charging current should not exceed C/20 and the charging threshold voltage is 0.2V lower than lead-acid battery types.
On the other hand, “gel” batteries are well suited for deep discharges and are. Used in tubular batteries because the gelled electrolyte eliminates the stratification of the electrolyte. Which is one of the main causes of the loss of open tubular batteries. Also visit: Dry Batteries Prices in Pakistan
Disadvantages of Gel batteries
The internal resistance of this type of battery is relatively high and therefore they do not support high charging and discharging speeds. Continuously, the charging current must not exceed C/10.
Gel batteries are therefore recharged relatively slowly. This point is important when the batteries are. Used for the storage of solar energy.
More than for other lead batteries, the charging parameters (floating voltage, charging and equalization, etc.) must be respected precisely: A Gel battery manufacturer writes that if the charging voltage exceeds the specified voltage by 0.7 V, battery life is reduced by 60%!
Note that the charging threshold voltage of gel batteries is 0.2V lower than other types of lead-acid batteries.
As with other Lead batteries, the life of Gel batteries is negatively affected by a rise in temperature (above 20°C, – 50% for life per 10°C increments for Flat Plate batteries, – 30% for tube sheets). As the charging voltage varies with temperature, gel batteries can be doubly affected if the charger and/or the charge regulator are not equipped with temperature compensation. This compensation is generally only essential if the temperature of the batteries varies outside a range defined by the manufacturer (15°C – 35°C).