Samplex Europe SEC-1245E, Руководство пользователя

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UNITS OF BATTERY CAPACITY
The battery capacity is the measure of the energy the battery can store and deliver to a load.
It is determined by how much current any given battery can deliver over a stipulated period
of time. The energy rating is expressed in Ampere Hours (AH). For example, as one of the
bench marks, the battery industry rates batteries at 20 hour rate i.e. how many Amperes of
current the battery can deliver for 20 hours at 26,7 º C till the voltage drops to 10.5 Volts
for 12 V battery and 21 V for 24 V battery. For example, a 100 AH battery will deliver 5
Amperes for 20 hours. Other bench mark discharge rates are 8-hour rate for UPS batteries
&10-hour rate for telecom batteries. Battery capacity is also expressed as Reserve
Capacity (RC) in minutes. Reserve capacity is the time in minutes for which the battery
can deliver 25 Amperes at 80 º F till the voltage drops to 10.5 Volts for 12 V battery
and 21 V for 24 Vbattery. Approximate relationship between the two units is as follows:
Capacity in AH = Reserve Capacity in RC minutes x 0.6
TYPICAL BATTERY SIZES
Below is a chart of some battery sizes applicable for powering inverters:
BCI * Group Battery Voltage, V Battery AH
27 / 31 12 105
4D 12 160
8D 12 225
GC2** 6 220
* Battery Council International ** Golf Cart
REDUCTION IN USABLE CAPACITY AT HIGHER DISCHARGE RATES
As stated above, the rated capacity of the battery in AH is generally applicable at a discharge
rate of 20 Hours. As the discharge rate is increased, the usable capacity reduces due to
“Peukert Effect”. This relationship is not linear but is more or less according to the table
below:
Table 1. Battery Capacity versus Rate of Discharge for a 20 Hr Discharge Rate 0
Hours of Discharge Usable Capacity
20 100%
10 87%
8 83%
6 75%
5 70%
3 60%
2 50%
1 40%
Using the above table will show that a 100 AH capacity battery will deliver 100% (i.e. full
100 AH) capacity if it is slowly discharged over 20 hours at the rate of 5 Amperes. However,
if it is discharged at a rate of 50 Amperes then theoretically, it should provide 100 AH ÷ 50
= 2 hours. However, the Table above shows that for 2 hours discharge rate, the capacity is
reduced to 50% i.e. 50 AH. Therefore, at 50 Ampere discharge rate the battery will actually
last for 50 AH÷50 Amperes = 1 Hour.
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