4v 400mAh

 Battery vrla Sealed lead Acid 4v 400mAh

Sealed Lead Calcium Maintenance Free Battery is an advanced and economic rechargeable battery. 

It has several properties different from other types of batteries Maintenance Free - As it is valve-regulated, sealed and glass-mat is utilized, acid is trapped inside. So, refilling is not needed and is leak proof. Discharge voltage remains stable even in conditions of high-rate discharge current [For equipment needing a high-rate discharge current, it's far more stable than other battery types].No Memory Effect - Some batteries, say nickel-cadmium batteries, will become conditioned to provide small power after repetitious short usage/discharge. Low Self Discharge - The self-discharge rate for SMF battery is about 2-3% per month at room temperature compared with 20-30% for other common battery systems Long Service Life - Utilizing thick and massive calcium grids, SMF battery has a long service life High Discharge Rate - Since the internal resistance is low, the battery can provide high rate of discharge. Wide Operating Temperature Range - SMF battery is rated at 200C and will operate from - 600C to +600C when it is fully charged.

Constant Voltage Charging

Charging at constant voltage is the most suitable and commonly used method for charging batteries. The charger voltage must be stabilized in a narrow range and with a device to suppress the initial current to less than 0.3C. The initial current limitation can be accomplished by a constant-current regulator, a properly designed output-voltage from the power transformer, or by designing the overall impedance of the circuit (such as using a current regulating resistor). During the final stage of charge, the current decreases automatically. Show constant voltage charger circuits provided with constant voltage functions, composed of transformers, transistors, silicon diodes, IC’s etc.

Constant Current Charging

It is an effective method for supplementary charge of many batteries at one time in series during storage but the charging time must be strictly controlled. It is because if the charging is continued at the same rate for an extended period of time after the battery has reached a fully charged state, battery voltage rises excessively, water decomposes, heat generates, and a severe overcharge may occur resulting in a heavy damage to the battery. For longest life, it is not recommended to repeatedly use constant current charging for refreshing batteries