DC System Riddle No.1 - Battery short circuit current
How can I calculate the battery short circuit current? I just access to battery discharge curve which is issued by battery manufacturer.

#1
Sat, December 26th, 2009 - 20:08
it is not difficult. the battery short circuit currents for diffrent manifacturers are very similar so you can use the a similar known rate. besides if the internal resisatnce of battery is mentioned in catalogue if ypu divide the open circuit voltage of a cell by the internal resistance it yields to short circuit current.

#2
Wed, April 28th, 2010 - 19:12
If the manufacturer provides detailed discharge curves for individual cells or for a general design covering various cell capacities, the cell internal resistance may be determined graphically. The internal cell resistance is the slope of the “initial volts” line in the discharge curve (this is not the same resistance that would be measured with an impedance tester):

R Cell =ΔV /ΔI

where R Cell = cell internal resistance (Ω)
ΔV = voltage change (V1 – V2) corresponding to ΔI on initial volts curve (V)
ΔI = current change (I2 – I1) corresponding to ΔV  on initial volts curve (A)

Also the short-circuit current available from a battery is:

ISCB= VB / RB

where ISCB = short-circuit current at battery terminals (A)
VB = battery open-circuit voltage (V OC × N c) (V)
RB = total battery equivalence resistance including cell interconnection resistances (Ω)
Figure below shows typical short-circuit current magnitudes available at the terminals of telecommunications batteries. Variations can be expected for different brands and for models within a brand.