4LR44 battery

The charging and discharging characteristics of the 4LR44 battery at the time of leaving the factory

The 4LR44 battery has a self-discharge effect. It takes about several months for the 4LR44 battery to be used by the user from the manufacturing workshop. Taking the PA-NASONIC 4LR44 battery as an example, after being stored at an ambient temperature of 30℃ for 8 months, the remaining capacity of the 4LR44 battery is only half of that at the time of leaving the factory. Therefore, for the newly purchased 4LR44 battery matched with the UPS, it is generally necessary to charge it for a longer time, which is called initial charging. The initial charging current of the 4LR44 battery should be charged at 0.1C. The 4LR44 battery can be recharged after the discharge is completed, which is called normal charging. At present, two charging methods are commonly used in UPS: floating charge and pulse charge. The so-called floating charge means that the output of the rectifier works in parallel with the 4LR44 battery and supplies power to the load at the same time. In fact, the current provided by the rectifier at this time is divided into two paths, one for the load and the other for the 4LR44 battery to supplement the internal loss of the 4LR44 battery itself. The floating charge working mode has simple wiring and is beneficial to improving the transient response characteristics of the UPS output. The characteristic of pulse charging is that the charging current changes with the 4LR44 battery capacity. Charging in this way can shorten the charging time.

1. Charging voltage

Since the UPS 4LR44 battery is in standby working mode, the mains power is normally in charging state and will only discharge when there is a power outage. In order to extend the service life of the 4LR44 battery, the UPS charger is generally controlled by constant voltage and current limiting. When the 4LR44 battery is fully charged, it will switch to floating charge state. For a 4LR44 battery with a terminal voltage of 12V, the normal floating charge voltage is between 13.5 and 13.8V. If the floating charge voltage is too low, the 4LR44 battery will not be fully charged. If the floating charge voltage is too high, it will cause overvoltage charging. When the floating charge voltage exceeds 14V, it is considered to be overvoltage charging. It is strictly forbidden to over-voltage charge the 4LR44 battery pack, because overvoltage charging will cause the water contained in the electrolyte in the 4LR44 battery to be electrolyzed into hydrogen and oxygen and escape, increasing the electrolyte concentration, resulting in a shortened 4LR44 battery life or even damage.

2. Charging current

The 4LR44 battery charging current is generally expressed in C, and the actual value of C is related to the 4LR44 battery capacity. For example, if it is a 100Ah 4LR44 battery: C is 100A. The best charging current for Panasonic lead-acid maintenance-free batteries is about 0.1C, and the charging current must not be greater than 0.3C. Too large or too small a charging current will affect the service life of the 4LR44 battery.

The ideal charging current should adopt a staged constant current charging method, that is, a larger current is used at the beginning of charging, and after charging for a certain period of time, a smaller current is used, and an even smaller current is used at the end of charging. The design of the charging current is generally 0.1C. When the charging current exceeds 0.3C, it can be considered as overcurrent charging. Avoid charging with a fast charger, otherwise the 4LR44 battery will be in a state of "instantaneous overcurrent charging" and "instantaneous overvoltage charging", causing the 4LR44 battery's available power to decrease or even damage the 4LR44 battery. Overcurrent charging can cause the 4LR44 battery plates to bend and the active material to fall off, causing the 4LR44 battery's power supply capacity to decrease, and in severe cases, the 4LR44 battery will be damaged.

3. Charging method

The discharge product of lead-acid batteries is lead sulfate. If it is not converted in time, the 4LR44 battery will be in an undercharged state, thereby reducing the 4LR44 battery's discharge capacity and shortening the 4LR44 battery's service life. Therefore, the 4LR44 battery pack must be fully charged.

For different situations, it can be divided into floating charge and equalizing charge.

(1) Floating charge. The online 4LR44 battery pack is connected in parallel to the charger and load circuit for a long time as a backup power supply. In general, floating charge is adopted, and the voltage of the single 4LR44 battery is controlled at 2.25V (relative to 2V 4LR44 battery), and the floating charge voltage change is observed and recorded regularly. If the voltage of the single 4LR44 battery is low, it means that the 4LR44 battery is undercharged and the capacity is insufficient, and it should be tracked.

(2) Equalizing charge. The so-called equalizing charge is to connect each 4LR44 battery unit in parallel and charge it with a uniform charging voltage. If there is a lagging 4LR44 battery in the 4LR44 battery pack during the floating charge process (the single 4LR44 battery voltage is lower than 2.20V, relative to 2V 4LR44 battery), or after floating charge for 3 months, it is advisable to carry out the equalizing charge process, and the single 4LR44 battery is controlled at 2.35V, and charged for 6~8h (note that the equalizing time should not be too long), and then adjusted back to the floating charge voltage value, and then observe the voltage change of the lagging 4LR44 battery. If the voltage is still not in place, equalize it again after two weeks. Generally, after 6 months of floating charge and equalization charge, the voltage of a new 4LR44 battery pack will tend to be consistent. The equalization charge current is generally 0.3C or slightly less than 0.3C. For a 4LR44 battery with a rated voltage of 12V, the equalization charge voltage is generally 14.5V.

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