SAMLEX AMERICA INC. | 19
Reserve capacity is the time in minutes for which the battery can deliver 25 Amperes at
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battery and 42V for 48V battery.
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Capacity “C” in Ah = Reserve Capacity in RC minutes x 0.6
7.5 TYPICAL BATTERY SIZES
The Table 7.1 below shows details of some popular battery sizes:
TABLE 7.1: POPULAR BATTERY SIZES
BCI* Group
Battery Voltage, V
Battery Capacity, Ah
12
105
%
12
%
12
225
($
220
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7.6 SPECIFYING CHARGING / DISCHARGING CURRENTS: C-RATE
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stored energy is related to the amount of the active materials pasted on the battery
plates, the surface area of the plates and the amount of electrolyte covering the plates.
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the battery and is designated by the symbol “C”.
The time in Hours over which the battery is discharged to the “End Point Voltage” for
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as the “C-Rate”. If the battery delivers a very high discharge current, the battery will be
discharged to the “End Point Voltage” in a shorter period of time. On the other hand,
if the battery delivers a lower discharge current, the battery will be discharged to the
“End Point Voltage” after a longer period of time. Mathematically:
EQUATION 1: Discharge current “C-Rate” = Capacity “C” in Ah ÷ Discharge Time “T”
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TABLE 7.2: DISCHARGE CURRENT RATES - “C-RATES”
Hours of discharge time “T” till
the “End Point Voltage”
"C-Rate" Discharge Current in Amps =
Capacity "C" in Ah
÷
Discharge Time
"T" in Hrs.
Example of C-Rate
Discharge Currents
for 100 Ah battery
0.5 Hrs.
2C
200A
1 Hrs.
1C
100A
5 Hrs. (Inverter application)
C/5 or 0.2C
20A
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`
SECTION 7 |
General Information on Lead Acid
Batteries
