Floating voltage = open circuit voltage + polarization voltage
=(electrolyte specific gravity +0.85)+(0.10～0.18)V
=(1.30+0.85)+(0.10～0.18)V
=2.15V+0.10V
=2.25V
For example, the specific gravity of the battery electrolyte of the United States Shengdi Company is 1.240g/cm3, so its float voltage is 2.19V. The float voltage of Japan's YUASA company is 2.23V.
The floating charge current of the fixed acid-proof explosion-proof battery has two functions:
1) Supplement the loss of battery self-discharge;
2) Provide current to daily loads.
The floating charge current of VRLA batteries has three functions:
1) Supplement the loss of battery self-discharge;
2) Provide current to daily loads;
3) The floating charge current is sufficient to maintain the oxygen circulation in the battery.
Deviation of terminal voltage (static deviation and dynamic deviation)
The dynamic deviation is relatively large in the initial stage of floating charge operation. In fact, the battery that has just left the factory may be affected by the saturation of the electrolyte in some of the batteries, which affects the oxygen recombination reaction, so that the float charge voltage is too high, and the battery with saturated electrolyte will decompose the water due to continuous charging. "Automatically adjust" to a non-saturated state, and the voltage deviation at the end of the 6-month period will gradually decrease. However, the large deviation does not rule out that it is related to the manufacturing quality of some manufacturers.
my country's GB13337.1-Q1 and Germany's DJN43539-84 stipulate that the static deviation range of fixed batteries is +0.1～0.05V of the average voltage.
According to YD/T799-1996 of the Ministry of Posts and Telecommunications, the deviation between the highest voltage and the lowest voltage value is 20mV in static state, and the deviation between the highest voltage value and the lowest voltage value should not exceed 50mV in dynamic state.
The Ministry of Electric Power DL/T637-1997 stipulates that the deviation between the highest voltage and the lowest voltage value is 30mV in static state, and the deviation between the highest voltage value and the lowest voltage value should not exceed 50mV in dynamic state.