WHAT IS A COLD TEST CURRENT?
Cold start current is a measure of a battery's starting capability at low temperatures of -18 °C.
1. DIN (Deutsches Institut für Normung e.V. - German Institute for Standardisation ) DIN EN 50342
Testing is carried out at –18 °C. The discharge time should be at least 10 seconds after discharging with the cold test current Icc at a final voltage of 7.5 V. In addition, the battery must fulfil 2 further requirements. The time to 6 V final voltage should be:
after C1: t6V ≥ 90 seconds
after C2: t6V ≥ 150 seconds
2. SAE (American Standard)
Testing is carried out at –18 °C. The discharge time with the cold test current up to 7.2 V should be at least 30 seconds.
3. IEC (International Electrotechnical Commission) 95-1
Testing is carried out at –18 °C. When discharging with the cold test current (Icc), the voltage should still be at least 8.4 V after 60 seconds.
4. EN (European Standard) DIN EN 50342
Testing is carried out at –18 °C. The discharge time should be at least 10 seconds after discharging with the cold test current Icc at a final voltage of 7.5 V. In addition, the battery must fulfil 2 further requirements. The time until 6 V final voltage should be: after C1: t6V ≥ 90 seconds after C2: t6V ≥ 150 seconds
Since the prescribed gradations are defined in the EN, the currents are determined by upward or downward gradations:
< 200 A – Level 10 A
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 – Level 40 A (640, 680, 720, 760 A)
> 800 A – Level 50 A
When comparing batteries, pay particularly close attention to the capacity!
The capacity (K or C value) of a battery depends on the current with which it’s discharged. The lower the discharge current, i.e. the longer the discharge time, the greater the usable capacity. And vice versa, the greater the discharge current, the less the available capacity. The “K or C” index always indicates the discharge time in hours.
Because the capacity is usually more important than the cold start!
A few facts to briefly take note of: massively increased energy requirements in modern cars, the original batteries that are sometimes designed too tightly, as well as retroactively installed consumers ranging from the auxiliary heating to the sound system.
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