A Mathematical Model for Float Operation of Valve-Regulated Lead-Acid Batteries

Valve-regulated lead-acid batteries are often used in uninte-rruptible power supplies. In these applications, the battery is continuously charged at low voltage to avoid gradual self (dischlarge. During float charging, SCVCIeral rCeqlir-emients have to be imiet: * In each cell positive and negative electriodes should be polarized sufficiently to maintain full state of charge. . The rates of water decomposition and grid corrosion shiould be as low as possible to ensure long service life. . Scattering of cell voltages in a battery string shlold be small, to allow a relatively low float voltage and to avoid non-unifor-mii ageing of cells. In the scope of an investigationi of factors relevant to thsce irequireIcints. a ma(tlhemiiatical model for float charging of lead-acid batteries has been developed, describing cffects otf float conditions and kinetic cell paramleter s on electrode potentials and electrode reaction rates.