Charger efficiency

A lot has been written, assumed, wrongly (and rightly) measured and interpreted about the efficiency of the charger. The biggest problem has always been that the big capacitors in the the charger filter section create a fairly large phase shift (phi) so real power is not the same as RMS voltage times current. This is not inefficiency. It’s, at most, ineffectiveness.

I have been in contact with an Italian professor in Power Electronics and he has put an R110 on some serious lab equipment. The results are as follows

Set point current (A)Power battery (W) *)Power AC (W)Current AC (A)Power efficiency (%)
326043707031.685.5
285325630028.184.5
244366523023.483.5
203543427019.681.1
162840356016.280.7
131881254011.874.1
10134119409.369.0

*) Battery power (DC) was derived from CanZE, voltage times current

Conclusion: If charging at a 16A setpoint (single phase), the efficiency is only a few percents lower than the highest measured. 85.5% is nothing to write home about but not bad. 80.7% at 16A is surely not as bad as some people would like you to believe.

I hope to get my hands on some 3 phase measurement. There is reason to believe the efficiency could be better, as there is a lot less curve following to do.

4 Comments on “Charger efficiency

  1. I have tried to measure as well with much less qualified equipment. However, there is a huge difference when charging and the battery cooling (or heating) system is running or not. So the above number should state to what extend the cooling (or heating) was in operation. I was only able to measure using a metering device vs. the CanZE values on a R90. The values have been at 11kW:
    96% (!) without cooling
    82% with cooling

    so my second measurement (with cooling) matches the above results at 16A pretty good. The measurement was taken in spring time in the evening. So ambient temperature was rather cool. Since I charge only during night, I usually can charge without cooling activated which makes a big difference obviously.

    Is there a statement from the person measuring under what conditions the charging has taken place? I was always wondering if the 96% can really be that high.

    • I will ask about the cooling, though I suspect it was not cooling, maybe just the back fans. 96% sounds unrealistically high, to be honest. But, I am promised to get 3 phase data too, so we’ll see.

      Edit: answer: there was PROBABLY no cooling, but can’t be 100% sure unfortunately.

  2. I assume this is all 1-phase testing. Isn’t the ‘ineffectiveness’ mostly applicable to 3-phase charging? Any data on 3-phase as well?

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