THE RULES IN FORCE FOR THE CALCULATION OF THE BATTERY INPUT
The cold test current is a criterion for measuring the starting capacity of a battery at temperatures below -18 ºC.
DIN (German industry standard) 43 539 T2 The test is carried out at - 18ºC.
The fully charged battery is discharged with cold test current (lCC) up to 6 V. After 30 seconds the voltage must still be at least 9.0 V (U30 ³ 9.0 V) and the period until reaching 6 V must still be at least 150 seconds (16V> 150 sec.).
SAE (American Standard) The test is carried out at -18 ºC.
The discharge time with cold test current up to 7.2 V must be at least 30 seconds.
IEC (International Electrotechnical Commisslon> 95-1 The test is carried out at -18 ºC.
In a discharge process with cold test current (lCC) after 60 seconds, the voltage must still be at least 8.4 V.
EN (European Standard) 60095-1 The test is carried out at -18 ºC.
In a discharge process with a cold test current (lCC) at a closing voltage of 7.5 V, the discharge time must be at least 10 seconds.
In recent years, the latter has become the standard method of expressing the cue.
Also, the battery must meet two further requirements. The period up to the closing voltage of 6 V must be equal to:
Based on C1: t6V ³ 90 seconds
Based on C2: t6V ³ 150 seconds
Since the prescribed levels are defined in EN, the currents will have to be adjusted up or down:
<200 A - 10 A level
200 - 300 A - level 20 A (220, 240, 260, 280 A)
300 - 600 A - level 30 A (330, 360, 390, 420, 450, 480, 510,540, 570 A)
600 - 800 A - 40 A level (640, 680, 720, 760 A)
> 800 A - level 50 A
THE RESERVE CAPACITY
Reserve capacity is the reserve of energy that the battery can provide in terms of minutes in the event of an alternator failure until the nearest repair shop can be reached.
However, it depends on the car users.
The IEC provides for the following test:
Discharge with 25 A up to a closing voltage of 10.5 V at a temperature of 27 ºC. Time measured in minutes = Reserve capacity