Bringing this thread back.
I have a JuiceNet pro 40amp EVSE. I got my M3 AWD Dec 29th (just in time for the full tax credit). I was curious as to my usage as reported by the car compared to my charging as reported by the JuiceNet. I am disappointed by the result.
I reset a trip meter when I got the car so I would have lifetime stats. The car is showing 345KWh used so far. I took a look at the JuiceNet logs and they show I have sent 425.19KWh to the Model 3. I have only done one smallish SuperCharger session so far, so the actual is even a little worse. This represents a 81% charge efficiency (not including the loss sent to the JuiceNet that is lost before being sent to the car). Is this low efficiency the car's issue or the JuiceNet? All of the research I have seen points to a much higher Level 2 charging efficiency - IEEE states that the mean L2 charging efficiency is 89.4%. I am in Southern California and charge in the garage, so temperature is not a factor.
The only other factor that might contribute is that the the median charge amount is 7.52KWh - IEEE again states that "In those charges in which the battery took up less than 4 kWh, this difference in efficiency was even greater: 87.2% for Level 2..." So I would think this would increase, not decrease the overall efficiency.
I took a look at the Edmund's article @
jsmay311 refereed to, with a little higher efficiency then I am getting, the the graphics did not load, so I can not see the relevant data.
Bottom line - all the research materials point to a MUCH higher charge efficiency then I see or Edmund's apparently saw.
Any ideas?
IEEE abstract for reference (if you are interested) -
A comparison of electric vehicle Level 1 and Level 2 charging efficiency - IEEE Conference Publication
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Adding this thought - I seem to recall somewhere reading that the usage the car reports is for driving only, not 'idling'. As I do a fair amount of sitting in the car waiting for the kids at practice, I wonder if this has an impact. And if you are wondering, I do occasionally (when the car actually wakes up) pre-condition when the car is plugged in. But this is for 5 minutes max, so I can't image that is skewing things much.