12 VERSUS 24 V?

Can you please shed light on the use of 12 V electrical systems in cars and 24 V systems in trucks?

Would simply upping the battery size not be sufficient to keep all at 12 V? JEREMIAH MNISI Hazyview This is a valid question and there was a time when 6 V systems in cars were common. The main reason for upping the voltage is because of increased powerconsumption needs. Remember, electrical power equals voltage times ampere (P=VI). Therefore, to lower the amps through cables (as the amps determine the thickness needed) in high-power auxiliary applications, it is beneficial to increase the voltage. For example, many electric vehicles run at close to 400 V on the main battery to lower the amp draw by the main electric motor (and reduce cable thickness and mass).

Trucks normally run 24 V systems for the same reason, as their auxiliaries require more power than needed in a passenger car. Example: 240 W in a 12 V system needs 20 amperes through the cable. The same 240 W demand in a 24 V system would require

10 amperes through the cable.

With mild-hybrid systems being introduced in many vehicles employing electrical integrated starter-generator (ISG) units of a couple of kilowatts, 24 V – or even 48 V – may become the new default operating voltage of vehicles.