Hot Cranking Amps (HCA) basically refer to the amount of current a battery can provide at 80° F. The definition includes the amps the battery can deliver and maintain for 30 seconds at the minimum of 1.2 volts per cell. This is a long definition which actually bares little relevance, as modern automotive industry requirements are based upon Cold Cranking Amps (CCA).
Most products displaying HCA rating promise better performance in warmer climates, but keep in mind that only CCA and CA (Cranking Amps) ratings are approved by the Battery Council International(BCI). The Cranking Amps rating is calculated by testing battery’s performance at 32 F or 0 C, for 30 seconds, maintaining at least 1.2 volts per cell. CCA is similar, but the temperature during testing is lower – 0 F or -17.8 degrees C.
So to summarize – Cranking Amps determine how much power you have to start your vehicle in most climates, Cold Cranking Amps do the same but for colder climates and Hot Cranking Amps – for warmer climates. Keep in mind that the HCA rating is not a standard and is not approved by the Battery Council International(BCI).