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If you used the same unit with both AC and CCS to charge the same car, the AC will use more to gain the same amount of battery charge due to losses in the AC charging, where as DC goes straight into the battery
 

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Renault ZOE ZE40 i Dynamic Nav June 2017
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If you used the same unit with both AC and CCS to charge the same car, the AC will use more to gain the same amount of battery charge due to losses in the AC charging, where as DC goes straight into the battery
The conversion losses for converting from AC to DC have to occur somewhere.

For an AC charge point the AC-DC converter is in the car (the charge point is not a charger), so the power losses occur in the car. For a DC charge point the converter is in the charge point (it is a charger) and the losses occur in the charge point. If the efficiency of the two converters is the same, the power loss will be the same.

I guess (can anyone confirm) that all charge points charge the user for the AC electricity consumed before the AC-DC converter. That is, you get charged for the AC power used, including any inefficiency in the conversion, in both cases. In that case, with the same efficiency conversion, the AC and DC heads on the charge point should use the same amount of AC power to put the same amount of energy into the battery, and you would be billed the same amount.

Of course, the car converter may be less (or more) efficient that the one in the charge point.
 

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That’s an interesting question. I’ve always understood that the DC delivered is what is charged for, so the network takes the hit on the conversion losses. When Björn does his range tests, he’s never included an additional % for losses in converting the AC to DC at the charge point, just the amount the charger has supplied. That does mean that AC charging costs us more then I guess, as the owner takes the hit in conversion losses at the car.

What I would like to know is what is the loss from DC charging, as it must be less than AC charging? There will be some losses as heat, but they must be less than when AC charging.
 

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From what I observed from the ABB Terra charging stations, they all show "kWhs delivered to the car", so the measurement takes place pretty much just before the kWhs leave the charging unit, not what is drawn from the mains - think this is an important distinction.

AC charging
The charger is on-board, so what the charging unit delivers is very close to what's being drawn from the mains and different than what goes into the battery; most losses are incurred by the car on-board charger. The charging unit will show how many kWhs have been drawn from the mains which is pretty similar to what's being sent to the Type-2 cable, as it has no clue about the efficiency of the on-board charger and so cannot calculate how much is actually going into the battery.

DC charging (speculative, I don't have yet the ABB Terra diagrams)
The charger is in the charging unit, so what the charging unit delivers is different than what is being drawn from the mains and very close to what is going into the battery; most losses are incurred by the charging unit during the rectifying (heat losses); exception would be the Taycan which runs on 800V and may have a second rectifier on board when charging from from a 400V charging unit. The charging unit will show how many kWhs have been delivered to the cable, not what's been drawn from the mains.

I believe that this is what explains the price difference, at least in Germany, between AC (29 cents) and DC (39 cents) charging, at the same charging unit. Price difference is quite high (about 33%), but it cannot be justified only by the wear and tear of the bridge rectifier and cooling fans, and I believe it takes into account to pay for the losses.
 
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