Quote:
Originally Posted by redpoint5
I don't quite follow your question.
Let me give an anecdote though;
I went from charging my Prius at 120v (L1) and 12 amps to charging at 240v (L2) and 12 amps (same EVSE modified to accept the higher voltage). Doubling either the voltage or the amps doubles the wattage. That means it takes half as long to charge the Prius. The line losses (which are fairly negligible) remain exactly the same because I'm charging at the same amperage.
The only explanation for that resulting in cutting losses in half is that the vehicle spent half the time running pumps and fans and relays and computers during the charging process. It spent half the time charging because it charged at twice the power.
Furthermore, 100% of line losses exhibit as heat, so if there was major line loss, the cables themselves would get quite hot. If someone was charging at 10 kW, and there was 10% line loss, that would be 1,000 watts of heat generated in the cable, which is a huge amount of heat. The cable would burn up, because it wasn't designed to be used as a space heater.
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The charger will only draw a fraction of what the conductors are rated for. It's a passive safety factor built in to all of them.
You cannot have line losses, as it's structurally impossible develop a voltage drop, which would affect the current draw.
The losses occur within the voltage step-up transformer windings.( You may have seen utility linemen pointing infrared scanners at pole-mounted trans-formers ).
A transformer converting 120-VAC into 400-VAC, then rectifying it into 400-VDC will have more heat loss than a 240-VAC transformer stepping up to 400-VAC, then 400-VDC.