a. Control the power charged, avoid overcharge, to reduce the amount of gas degassed.

b. No open fire near the batteries during charging process and keep good ventilation.

c. During charging, the connection should be firm to avoid sparks due to loose connection.

d. Adopts constant current and limited voltage charging method, which generates less gas evolution.

e. Prevent sparks or even fire and explosion due to short circuit.

f. Keep the degassing hole unobstructed for the maintenance-free sealed batteries, otherwise, the increased internal pressure may accumulate too high to cause bulge or even explosion.

a. If density is too high, it will cause plate sulfation and accelerate grid corrosion; while if desnity is too low,it will affect discharge capacity.

b. Under normal charging conditions, if the density does not increase significantly or even remain unchanged, there is a possilibity of plates sulfation , which may need countermeasures to eliminate sulfation.

c. After the battery is charged, if the density decreases significantly during the resting period, it indicates the sever battery self-discharge, which may be caused by too much impurities in electrolyte. If electrolyte shows abnormal color or smell, or even shows turbidity, it indicates that the electrolyte is impure and impurities has got into the battery.

d. If electrolyte shows the color of metal ions, there is a possibility of contamination.

The high temperature of electrolyte after acid filling of new batteries is due to the neutralization reaction between the acid and the oxidized negative plates, which will generate lots of heat. During this period, charging shoud start when the electrolyte temperature drops to about 40 ℃, or charge the battery with low current.

During normal charging process, if electrolyte temperature is high or even exceeds 45℃, cooling measures should be taken, or adjust the charging current to a low value. If temperature shows no decrease, possibility of battery internal short circuit or plates sulfation should be considered.

During normal usage of battery, if the temperature is too high. There are two possilibities to this: one is because the surrounding ambient temperature is too high, and the heat generated by battery is not easy to dissipate. The other is that the charging voltage or current is too high.

When recharge a normal battery, no massive bubbles(gas) would be generated at the  primary charging period, since the current charged only serves for the electrochemical reaction of active mass. While at the end of charging period, along with the completion of electrochemical reaction, current charged begins to electrolyze water, and degases hydrogen and oxygen.                                                                               

When recharge the battery after usage, if only little gas is generated at the end charging period, it may be because the charging current is too low or battery is still not fully charged.If one single cell shows no gas generation during battery charging, this may indicate internal short circuit.If the whole battery produces too much gas and too early, this indicates the possibility of plates sulfation, which shoud be treated with repeated discharge and charge processes. If the battery produces gas in resting period or discharge process, it may be caused by much impurities in electrolyte.

After charging, the voltage of each single cell should be around 2.1V(may be affected by elctrolyte density ). If the voltage is low during primary usage, check if battery is fully charged or if electrolyte density is too high or too low .

If battery shows comparatively higher voltage during charging, along with numerous bubbles,and voltage drops fast during discharge, this may indicate plates sulfation. Fully discharge the battery with low current and then charge the battery with low current (0.1C20), repeat the discharge and charge steps several times. The effect of this method may be affected by the sulfation degree.

a. Sulfation; (over-charge, repeated charge, hydrotherapy for desulfurization )

b. Pollution of electrolyte; (after multiple flushings with distilled water, change the electrolyte)

c. Whether batteries show partial short circuit.

d. Phenomena like grid corrosion, plate breakage, active mass shedding,etc.at the end of service life.