【 Weak current College 】 battery floating features】

(1) floating charge voltage

Battery for floating charge flow should meet compensation battery discharge current and maintain oxygen cycle needs. Lead-acid battery of floating charge voltage can be determined by the following formula:

Floating charge voltage = open-circuit voltage + polarization voltage

= (Electrolyte density + 0.85) V + (0.10 ~ 0.18) V

Valve regulated lead acid battery electrolyte for 1.30g/cm3, which is open-circuit voltage is 2.15V, single cells floating charge voltage of 2.25 ± 0.02V/a (25 ° c).

(2) end voltage deviation (static errors and dynamic errors)

Valve regulated battery voltage deviation there are two types of static state voltage deviation, i.e. open-circuit voltage deviations, the deviation shall not exceed 20mV; the second is a dynamic error, i.e. float State deviation, the deviation of the values in floating charge run into larger, run in the early days of 2 ~ 3 months will be gradually reduced. This is because the initial status of circulating compound of oxygen is not stable, as the running time increases oxygen cycle composite status will become more stable, Terminal voltage deviation. Therefore, the floating charge running Terminal voltage deviation value that is greater than static state.

When the average floating charge voltage change, deviation value also in changes in the average floating charge voltage, the higher the deviation increase, decrease, but instead the deviation. Battery remaining capacity and floating running battery terminal voltage of no direct relationship, it is difficult to judge from the battery terminal voltage high capacity of its surplus, end-to-voltage lower its surplus capacity is small.

(3) float charging current

Float charging stream If value should meet compensation battery from discharging current Is and oxygen compound current Ir. Therefore:

If≥Is＋Ir

Valve-regulated sealed lead acid battery self-discharge rate it is very small, so the corresponding float charging current values are very low. Japan standard in 80% of the rated capacity of one-night self-discharge rate not greater than 0.2%, even by 1%, then the battery from discharging current set temperature (20 ° c and 25 ° c), Is = (C10/24) × (1/100) = 0.00042C10A, calculation of Ontario by company Is = 0.42mA/Ah. Then take into account the needs of the oxygen cycle compound, floating charge flows through If = 1mA/Ah has been able to meet the requirements.

Since the discharge current (Is) in which a majority are used for grid corrosion (order corrosion current to Ic, Ic Is ≥), while oxygen compound current due to the presence of oxygen compound efficiency, only a small part is used to break down water. In this way, different grid materials, different manufacturing process, the floating charge flow naturally different. The smaller the floating charge flow, also means that on a grid of corrosion current and water loss of current.

(4) floating charging current relationship with life

Battery operating life and grid corrosion rate and water level. Grids of corrosion in the same alloy material condition, and the concentration of sulfuric acid electrolyte and electrolyte temperature: when battery floating charge voltage, and high proportion of the electrolyte, and floating charging current is large, the grid of the corrosion rate is large, it will inevitably lead to elevated temperatures, water loss speed, battery operating life of float also reduced. Small floating charge flow will achieve higher float operation life.