22 | SAMLEX AMERICA INC. SAMLEX AMERICA INC. | 23
80ºF (26.7ºC) till the voltage drops to 1.75V / Cell i.e. 10.5V for 12V battery or 21V for
24V battery.
Approximate relationship between the two units is: Capacity “C” in Ah = Reserve
Capacity in RC minutes x 0.6
7.5 TYPICAL BATTERY SIZES
The Table 7.1 shows details of some popular battery sizes:
TABLE 7.1: POPULAR BATTERY SIZES
BCI* Group Battery Voltage, V Battery Capacity, Ah
27 / 31 12 105
4D 12 160
8D 12 225
GC2** 6 220
* Battery Council International; ** Golf Cart
7.6 C-RATE OF CHARGE / DISCHARGE
7.6.1 The rate of charge / discharge of a battery is normally expressed in “C-rate”
which is a multiple of the numerical value of the battery’s Ampere Hour (Ah) Capacity
(C) (See Section 7.3 for information on Ampere Hour Capacity). Few examples of C-rates
(2C, 1C, 0.2C etc.) for 100Ah capacity battery (C=100 Ah) are given below:
• 2C = (2x100) A = 200A (As the battery capacity is 100 Ah, the battery will be
completely discharged in 0.5 Hrs.)
• 1C = (1x 100) A = 100A (As the battery capacity is 100 Ah, the battery will be
completely discharged in 1 Hr.)
• 0.2C (or C/5) = (0.2 x 100) A = 20A (As the battery capacity is 100 Ah, the battery will
be completely discharged in 5 Hrs.)
7.6.2 Example for Determining C-rate of Charge for Particular Value of
Charge Current:
• Determine the Ah capacity (C) of the battery – say 100 Ah (C=100 Ah)
• Determine the value of charge current – say 10 Amperes
• C-rate of charge at 10A = Multiple of numerical value Ampere Hour Capacity (C) =
(10 ÷ 100) C = 1/10 C or 0.1C
7.6.3 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
7.6.4 Table 7.2 gives some examples of typical C-rates of Discharge and applications:
SECTION 7 | General Information - Battery Related
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