Samlexpower PSE-12125A, Руководство пользователя

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16 | SAMLEX AMERICA INC. SAMLEX AMERICA INC. | 17
Table 6.2 below gives some examples of c-rate specifications and applications:
tABle 6.2: 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
8 hrs.
(uPS application) c/8 or 0.125c 12.5A
10 hrs.
(Telecom application) c/10 or 0.1c 10A
20 hrs.
(Automotive application) c/20 or 0.05c 5A
100 hrs. c/100 or 0.01c 1A
note:
when a battery is discharged over a shorter time, its specified “c-rate” discharge current
will be higher. for example, the “c-rate” discharge current at 5 hour discharge period i.e. c/5
Amps will be 4 times higher than the “c-rate” discharge current at 20 hour discharge period i.e.
c/20 Amps.
charging / Discharging curves
fig. 6.1 (page 18) shows the charging and discharging characteristics of a typical 12V /
24V lead Acid battery at electrolyte temperature of 80°f / 26.7°c. The curves show the
% State of charge (X-axis) versus terminal voltage (y-axis) during charging and discharg-
ing at different c-rates. Please note that X-axis shows % State of charge. State of
Discharge will be = 100% - % State of charge. These curves will be referred to in the
subsequent explanations.
Reduction in Usable capacity at Higher Discharge Rates –
typical in inverter Application
As stated above, the capacity of automotive battery is normally applicable at a discharge
rate of 20 hours. As the discharge rate is increased as in cases where the inverters are
driving higher capacity loads, the usable capacity reduces due to “Peukert Effect”. This
relationship is not linear but is more or less according to the Table 6.3 (page 18).
seCtIOn 6 | General Information on
lead Acid Batteries