I was just thinking if you are on your computer anyway would it just use some of the excess electricity that your computer would have wasted or would it be worse than charging your phone from a charger while using your laptop separately.
I was just thinking if you are on your computer anyway would it just use some of the excess electricity that your computer would have wasted or would it be worse than charging your phone from a charger while using your laptop separately.
I’ve previously spoken with PSU engineers for enterprise power supplies – specifically for 48-54v PoE equipment – who described to me that today’s switch mode power supplies (SMPS) tend to get more efficient with increasing load. The exception would be when the efficiency gains from higher loading start to become offset by the heating losses from higher input currents.
This graph for a TDK PSU shows that North American 120 VAC nominal (see here for the small difference between nominal and utilization voltages) will cause a small efficiency hit above 75% or so. And this is exactly why data centers – even in North America – will run with “high line” voltage, which is 200 VAC or higher (eg North American 208VAC delta supplies, British 240/415 wye, European 230/400 wye).