Annexure 23 - Generator Battery Test

Annexure 23

Annexure 1 Prepared by Rohitha Rajaratne
Battery Visual Inspections

1. Check for cracks in the battery case and broken terminal. Either may cause electrolyte leakage,
which requires to battery replacement.

2. Dirt or acid on the case top. Use one of the following solutions to clean properly
 A mixture of 0.1kg of baking soda and 1 liter of clean water
 A mixture of 0.1 liter ammonia and 1 liter of clean water

3. Check for cracked or broken cables or connections. (Replace as needed)

4. Check for corrosion on terminal and cable clamps (use fine grade of sand paper to clean
terminals and cable clamps, clean the items until bright or shiny)

5. Check for loose battery hold-down or loose cable connections. (tighten the cable/s or hold
down)

6. Check for cloudy or discolored electrolyte.

7. Check the electrolyte level through translucent plastic case or removing vent cap and directly
looking into each cell. (add distilled water if necessary do not over fill)

Figure 1

XXVi (1/6)

Annexure 2 Prepared by Rohitha Rajaratne

Open circuit voltage test

1. Disconnect battery from all the loads
2. Measure the voltage using DC voltmeter
3. Check the state of the charge using Table 1 below
4. Recharge the battery if it registers 0% to 70% charged.

Percentage of Open circuit voltage
Charge
100 % 6V 8V 12V 24V 36V 48V
90 % 6.37 8.49 50.93
80 % 6.31 8.41 12.73 25.46 38.20 50.47
70 % 6.25 8.33 49.99
60 % 6.19 8.25 12.62 25.24 37.85 49.49
50 % 6.12 8.16 48.96
40 % 6.05 8.07 12.50 25.00 37.49 48.41
30 % 5.98 7.97 47.83
20 % 5.91 7.88 12.37 24.74 37.12 47.26
10 % 5.83 7.77 46.63
5.75 7.67 12.24 24.48 36.72 46.03

12.10 24.20 36.31

11.96 23.92 35.87

11.81 23.63 35.44

11.66 23.32 34.97

11.51 23.02 34.52

Table 1

Figure 1

XXVi (2/6)

Annexure 3 Prepared by Rohitha Rajaratne

Specific Gravity Test

3.1 Aim

To check charging level of the battery.

3.2 Specific Gravity testing procedure using hydrometer

1. Put on eye protection and rubber gloves.
2. It is recommended to disconnect the battery especially if on a high rate of charge /

discharge.
3. Remove vent cap. Carefully insert the hydrometer into cell. (Do not push down on the top

of the plates)
4. Carefully draw liquid into the hydrometer and avoid bubbles in the hydrometer (Figure

1). (Electrolyte should not splash or stick to the side of the glass tube)
5. Obtain a reading by looking directly at the electrolyte (Figure 2).
6. Return the electrolyte to the cell and replace the vent caps (wipe off any electrolyte that

might have been spilled).
7. Repeat steps 3 to 6 steps to reconfirm reading.
8. Repeat 3 to 7 steps to all cells.
9. RECORD the cell number and result.
10. Check the state using Table 1 below.

3.3 Temperature Correction

Add 0.004 to specific gravity reading for each 5°C above 25°C or subtract 0.004 from
specific gravity reading for each 5°C below 25°C

Charged Specific Gravity

100% 1.270

75% 1.230

50% 1.190

25% 1.145

0% 1.100

Table 1: Specific gravity at 250C

3.4 Observations

XXVi (3/6)

Prepared by Rohitha Rajaratne
 Each cell needs to have 75% charged or higher (specific gravity level 1.230 or higher

level).
 Variation in specific gravity among cells can not vary more than 0.05 (specific gravity

level variation in between the cell with highest specific gravity level and the cell with
lowest specific gravity)

Figure 1: Draw electrolyte from the cell

Figure 2: Check the electrolyte level by direct reading

XXVi (4/6)

Annexure 4 Prepared by Rohitha Rajaratne

Battery clamp - post resistance

Method

Use a volt meter to check resistance between battery post and the clamp.

Observations

Resistance must be equal to zero (0) else clean the post and clamp and recheck resistance.

Figure 1

XXVi (5/6)

Aitken Spence Hotel Management - Daily Battery maintenance log

Formulated by
Rohitha Rajaratne - VP Engineering

Battery No/Location : ……………………………. Month ………………………….

Maintenance Task 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

1. Visual Inspection (Annex 1)
1.1 Battery terminal tightness /corrosion
1.2 Electrolyte level
1.3 Battery case, cracks/dirt or acids
2. Open circuit voltage (Annex 2)
3. Specific gravity test (Annex 3)
4. Battery clamp - post resistence (Annex 4)

Remarks

…………………………………. ……………………………………….
Supervisor Chief Engineer

XXVI (6/6)