A valve-regulated lead-acid (VRLA) battery, is a type of lead-acid battery characterized by a limited amount of electrolyte ("starved" electrolyte) absorbed in a plate separator or formed into a gel; proportioning of the negative and positive plates so that oxygen recombination is facilitated within the cell; and the presence of a relief valve that retains the battery contents independent of the position of the cells.
According to the technology, there are two kinds of lead-acid batteries: general type (AGM) and GEL. AGM battery uses glass fiber cotton (Absorbed Glass MAT) as a separator, and liquid electrolyte (the electrolyte is absorbed on plate and separator, and cannot flow in the battery). The GEL battery has silica as a solidifier and the electrolyte is adsorbed on the plate as colloid.
Accordingly, to using purpose, they also can be mainly divided by usage: starting batteries, stationary battery, and traction type, etc.
In the conditions of the stipulated design (such as temperature, discharge rate, and final voltage, etc.), the rated capacity means the battery should be able to release the lowest capacity, the unit is ampere-hour, expressed as a symbol of C. Capacity is strongly influenced by the discharge rate, so we often show the discharge rate by Arabic numerals at the lower right corner of the letter "C", such as C20=50Ah, it means that under the condition of 20-hour rate to discharge to the final voltage,the capacity is 50 ampere hours. Informally, the rated capacity of 50 ampere hour of battery in full charge of state, the battery can be discharged for 50 hours with 1 A of current.
Refers to the battery in the non-work state which the condition of the battery without any external load current flows, the Value of battery voltage between two terminals is measured by an electric meter. The Open circuit voltage measurement can not be utilized as a standard to measure the battery voltage, but it can be compared with each other, it also can determine different time change state of the charged battery itself, as a reference.
End of discharge voltage is the allowable minimum voltage of battery discharging.
When the battery voltage is lower than the end of discharge voltage, the voltage of the battery will drop rapidly if discharge it continuously, and it will cased over-discharge of battery, once the compound of battery plate is formed, and the plate will not easy to recover, which affect the lifespan of battery. The End of discharge is connected with discharge rate, and discharge current affect the end-of discharge voltage directly. Under the stated end of discharge voltage, the greater discharge current, the smaller capacity of battery.
When the battery is fully charged, the active material of the lead plates had reached saturation; the battery voltage does not raise anymore, even charge it continuously.
During battery using, the battery capacity is discharged a percentage of it rated capacity, we called depth of discharge, generally, DOD with 60%, which means the discharged capacity of battery reached 60%, and remained 40% of capacity. It’s a deep connection between depth of discharge and charging life, when deepen the DOD, the.
Recycling: The battery as a direct power supply of the equipment, which is mainly applied for circulation charge and discharge of Electrical hand tools, Portable electronic products and etc.
Float Use: The battery as an emergency power supply for equipment and system, to provide emergency power or energy storage, in order to prevent any inconvenience if any power interruption (Example: power plant, UPS power supply, emergency lighting, etc.)
There are mainly constant current charging, constant voltage charging, constant current with limiting voltage charging, equalizing charging, float charging and pulse fast charging.
Floating charging: A battery powered by a circuit when the normal power supply is interrupted. The terminal is always connected with a constant voltage power supply to maintain the battery in a close state of charge.
Equalizing charging: It is a continued charging way to ensure that each monomer of battery will be fully charged uniformly
There are several reasons as below,
① The battery charge is insufficient or the first charge is interrupted with a long time;
② Undercharge with long time.
③ Failed to charge timely after discharge;
④ Over discharging with small current or over charging frequently
⑤ The density of electrolyte or the temperature is too high, lead sulfate is formed and not easy to recover.
⑥ Battery stocked with a long time, and and it isn’t charged regularly.
⑦ The of electrolyte is impurity, which caused quickly self-discharge.
It requires good ventilation facilities, dry conditions (preferably with air conditioning), to maintain the environment temperature at around 25 degrees Celsius; and the ground to bear ability is strong, after 3 months storage should be charged.（The place where the battery installated should be safe and stable, and the battery should be charged once every 3 months stocked.