Rolls Surrette User Manual

SPECIFIC GRAVITY

The specific gravity of electrolyte in a battery is the most accurate measurement

to determine if the cells are in fact, fully charged. The specific gravity should be

constant for 3 hours for an accurate full charge reading. Check the state of charge

as related to specific gravity. Initial charging may take 10 hours. Once the battery

is fully charged, verify the electrolyte level in the cell once more. The fluid should

be 1/4”-1/2” below the vent tube on each cell as shown in Figure 7. Carefully add

distilled water to adjust as needed.

* Check specific gravity regularly to confirm charging parameters are properly

programmed, avoiding possible over/undercharge, resulting in possible cell

damage or battery failure.

Special order batteries may be shipped dry (acid shipped separately). To activate these

batteries, start by removing the vent caps. Using approved battery grade electrolyte

(1.265), slowly fill each cell until the liquid level reached halfway between the plates

and the bottom of the vent well tube. (See Figure 7.) It is important not to over fill

the cells as the acid will expand upon charging. If the cells are too full, the acid will

overflow and require cleanup. Allow electrolyte to saturate into the plates and separators

for at least 90 minutes. The temperature of the electrolyte will rise and the specific

gravity will drop. Once this is complete, place the batteries on charge at the finishing

rate (5%-10% of the 20 hour rate). The rate may be increased if the battery does

not begin to bubble and gas. Do not let the cell temperature exceed 52°C (125°F). If

the temperature becomes excessive or the cells begin to gas vigorously, reduce the rate

of charge. Continue charging until the cell (or cells) reaches within .005 points of the

specific gravity of the filling electrolyte corrected for 25°C (77°F). We recommend

allowing the charge to continue for an additional 60 minutes to insure no further rise in

specific gravity. A longer lower charge rate is better than a higher heavier charge.

FIGURE 6:

Temperature

Sensor

TABLE 3:

Specific Gravity

vs State of Charge

% Charge Specic Gravity* (SG)

100 1.255 - 1.275

75 1.215 - 1.235

50 1.180 - 1.200

25 1.155 - 1.165

0 1.110 - 1.130

NOTE: Specific Gravity is dependent on the electrolyte temperature. These values are

for a temperature of 25°C (77°F). To adjust, add/subtract 0.003 for every 5°C (10°F)

increase/decrease.

ACTIVATION AND INITIAL CHARGE OF

DRY-SHIPPED FLOODED LEAD ACID BATTERIES