Valve controlled batteries are only set with a strict floating voltage (2.25-2.27V) for individual cells, mainly due to their unique structural principles. When charging under this floating voltage, the gas recombination efficiency generated inside the battery can basically reach equilibrium. Therefore, under normal floating conditions, there will be no excess gas left in the battery, thereby reducing the number of times the safety valve opens and closes. Start. Reduce losses and extend battery life.

The relationship between float inflation pressure and gas composite efficiency is as follows:

The combination efficiency of gases is closely related to the choice of floating voltage. The floating charging voltage is too low. Although the oxygen analysis rate is low and the recombination efficiency is high, individual cells may fail due to long-term insufficiency, leading to float charging passivation and shortening the battery life. If the float voltage is too high, the amount of gas released will increase and the gas mixing efficiency will decrease. The safety valve is mostly in the open state, which results in a significant loss of water and corrosion of the positive grille. It is generally believed that the water loss rate is 50%. The capacity has also decreased by 15%, at which point the battery life is considered to have ended.

The relationship between battery life and float charging voltage. Refer to Figure 5-1

From the graph, we can see the relationship between float voltage and battery life:

Floating voltage at 2.25V, with a single cell lifespan of 100%

The float voltage is 2.75V, and the individual lifespan is only 40%

The float voltage is 2.18V, and the individual lifespan is only 70%

For example, a 50AH UPS power supply with 2.27V/cell float charging has a combined efficiency of 99%. If each battery is used for more than 10 years, the water consumption is 40em3,

Only 5% of the total amount added.

Experience has shown that when performing permanent float charging at 2.4V per cell, the battery will

Expires in 18-24 months.