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1.4.10.3 Example for Determining C-rate of Discharge for Particular Value of Discharge Current:
• Determine the Ah capacity (C) of the battery – say 100 Ah (C=100)
• Determine the value of discharge current – say 20 Amperes
• C-rate of discharge at 20A =
Multiple
of numerical value of Ah Capacity (C) = (20 ÷ 100) C = 1/5 C
1.4.10.4
Table 1.4.2 gives some examples of typical C-rates of Discharge and applications:
TABLE 1.4.2 TYPICAL “C-rates” OF DISCHARGE
C-rate of Discharge
(Column 1)
Examples of C-rate of Discharge
for 100 Ah capacity battery
(Column 2)
2C
200A
1C
100A
C/5 or 0.2C (Inverter application)
20A
C/8 or 0.125C (UPS application)
12.5A
C/10 or 0.1C (Telecom application)
10A
C/20 or 0.05C (Automotive application)
5A
C/100 or 0.01C
1A
1.4.11 CHARGE / DISCHARGE CURVES TO DETERMINE STATE OF CHARGE OF LEAD ACID BATTERY
BASED ON ITS TERMINAL VOLTAGE AND C-RATES OF CHARGE / DISCHARGE
1.4.11.1
Fig 1.4.1 shows examples of State of Charge / Discharge Curves for different
C-rates
for typical 12V / 24V
/ 48V Lead Acid Battery Pack/ Battery Bank at 80°F / 26.7°C. These curves are used to determine the State of Charge /
Discharge of the Battery Pack/ Bank based on its terminal voltage.
The Y-Axis shows the terminal voltage of the battery. The X-Axis shows % State of Charge. % State of Discharge can
be converted to % State of Charge using formula:
• % State of Charge = (100% -% State of Discharge) e.g. 80% State of Discharge = 100%-80% = 20% State of Charge
1.4.11.2 Example of Determining State of Charge (using Fig 1.4.1) when Charging 48V, 100Ah Battery
Bank at C-rate of 0.1C or C/10 or 10A:
Refer to Charge Curve marked C\10 of the upper 4 curves marked
“CHARGE”
. States of Charge at different battery terminal voltages will be: (a) At 61.2V = 100% charged; (b) At 57.2V
= 90% charged; (c) At 54.0V = 70% charged; (d) At 50.0V = 15% charged
1.4.11.3 Example of Determining State of Discharge (using Fig 1.4.1) when Discharging 48V, 100Ah
Battery Bank at C-rate of 0.33C or C/3 or 33.3A:
Refer to Charge Curve marked C\3 of the lower 4 curves marked
“DISCHARGE”
. States of Discharge at different battery terminal voltages will be: [a] At 38.0V = 100% discharged
(
0% charged
); [b] At 41.6V = 80% discharged (
20% charged
): [c] At 46.0V = 28% discharged (
72% charged
) and [d]
47.0V = 0% discharged (
100% charged
)
SECTION 1.4 |
General Information
–
Battery Related
Содержание Evolution EVO-4248SP
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