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It sounds like you almost have enough numbers to calculate the ball-park efficiency.

Grid -> condo battery ~85% (basically an L2 charger)

Condo battery -> L3 charger let's say ~96%[0] because it's a high discharge rate

L3 charger -> car ~90%

It's simple math now: 0.85 * 0.96 * 0.90 = ~74% end-to-end efficiency.

[0] https://www.researchgate.net/figure/Energy-efficiency-map-of...




I don't think the efficiency can be partitioned like that. An L3 charger is supposed to output the same electricity that goes directly into the car's battery, with no additional conversion. An L1 or L2 charger has no conversion inside the charger - it's just a wire and a little electronic tag that says what the amperage is.


The losses are different, but still exist.

In the L3 case there is still a voltage conversion because the input voltage needs to be higher than the battery voltage in order to put energy into the battery. There will be a loss at that stage.

But a big part of the loss during L3 charging is in the battery chemistry. The relatively high charging rate is less efficient than slower charging rates. The high powers involved also generate heat, which often requires active cooling which is an additional reduction in plug-to-wheel efficiency.

In the L1/L2 case there is a conversion from ~240v AC to DC but it's inside the vehicle. Plus the battery chemistry charging losses, but they are much lower than in the L3 case.

These are all ballpark numbers anyhow, so you are welcome to suggest difference values which you believe are supported.




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