Hyundai 12ESH Operation Manual page 17

of the second stage to continue charging. When charging, the temperature of electrolyte shall never exceed 45℃.
When the temperature rises nearly to 45℃, reduce the current by half or stop charging temporarily. After the
electrolyte temperature reduces to below 35℃, continue charging, however the charge time needs to be extended
properly.
6.1.6 Evidence of full charge: When the voltage during the second stage charging reaches 31.2V (12 ×2.6V =
31.2V), the variation of the voltage is no greater than 0.005 (V); when the density of the electrolyte reaches 1.280
±0.005 (25℃), no apparent changes in 2 hours and there are fine air bubbles appear violently, it can be regarded
as that the batteries are fully charged. The charging amount is 4-5 times of the rated capacity and the charging time
is about 70 hours.
6.1.7 In order to accurately control the sulfuric acid content of the electrolyte, the electrolyte density of the
batteries should be examined during the last period of charging. If there is inconsistence, adjust with distilled water
or sulfuric acid with a density of 1.40. The electrolyte density and the liquid level should be adjusted to the stipulated
value within two hours in charging state.
6.1.8 After the initial charge is completed, the surface of the batteries should be cleaned. Close the cover of
the liquid hole plug and then the batteries can be used.
6.2 Use and maintenance
6.2.1 In order to guarantee the service life of battery, the battery in use should be fully charged. Insufficiently
charged battery must not be used. During the process of use, close attention should be paid to the discharge extent.
Over discharge is prohibited---the voltage reduces to 1.7V per cell (when the total voltage reduces to 1.7V×24
= 40.8V). When the density of the electrolyte reduces to 1.17, discharge should be stopped and charge should be
conducted at once. The battery should not be placed idle for an extended period of time. The supplementary
charge which is frequently conducted during use is called common charge.
6.2.2 Common charge: for common charge, current of the first phase is 30A, and the second phase is15A.The
charging method is the same as initial charge. The charge amount is 130-140% of the discharged amount. The
charging time is around 12hours.
6.2.3 The cells in normal use should avoid over-charge, but over-charge must be properly conducted for the
cells in following situations, i.e. equalizing charge.
a. The "lag-behind" cells--- cells with a voltage lower than that of the other cells in the discharging process and
the cells having been repaired for failure. (When equalizing charge is conducted, the positive and negative poles
of the "lag-behind" cell should be respectively connected with the positive and negative ends of the charger, the
DC power supply, and the charge should be conducted independently.)
b. Equalizing charge should be conducted for cells in normal use every 2-3 months.
c. Equalizing charge should be conducted for the cells which have not been used for a long period of time
before use them again.
6.2.4 Equalizing charge:
a. Charge with a 4A current.
b. When the charge voltage reaches 31.2V (12×2.6V =31.2V) and air bubbles occur in the electrolyte, the
current should be reduced by 50% (2A) and continue to charge.
c. When the cells are fully charged, stop charging for 0.5 hour and charge again with a 1A current for one more
hour.
d． Stop charging for another 0.5 hour and charge with 1A current for another one hour.
e． Repeat item d till air bubbles occur violently in the cells once the charger is switched on
13