I saw multiple old threads on the total charging efficiency of the Model S, but they all seemed to be the older 80A charger. Anyone have a ballpark figure of overall charging efficiency of the 72A charger on newer S/X and the Tesla HPWC? Looking for all losses - HPWC, wire runs, onboard charger, battery - how many kWh do I draw from the breaker panel for each kWh I see added to the car's battery meter. I'm just trying to estimate the total cost of fueling my car at home. I'm guessing it's 80% or 85%, given past posts and the fact that my car does get warm overnight in the garage when it charges, so I'm losing some to heat. Even the garage itself (a decent sized 3 car with high ceiling) warms up a bit. If it matters, I typically charge at 50A.
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overall charging efficiency of 72A chargers and HPWC?
- Thread starter Magellan55
- Start date
Tam
Well-Known Member
Not sure about the S but for my 2017 X, the best efficiency that I can see is only about 93%
Charged from 80% to 90%. Added 9.7kWh but used 10.4kWh from the outlet:
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Tam
Well-Known Member
I pulled up my old record for my 2012 Model S: Best efficiency is 92%
Charged from 78% to 90%. Added 9.0kWh but used 9.8kWh from the outlet:
Charged from 78% to 90%. Added 9.0kWh but used 9.8kWh from the outlet:
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Tam
Well-Known Member
No matter low or high, long or short, I could randomly hear the HVAC scream like a helicopter ready to explode!
2012 85 Model S:
Charged from 25% to 69%. Added 33.0kWh but used 36.8kWh from the outlet: Efficiency is 92%. Note that I decreased the Amperes down to 20A
Just wondering if you calculated the ambient temperature, the underground temperature and your car's tank's temperature when filling up with gas?
Tam
Well-Known Member
2018 Model 3 LR:
Charged from 37% to 100%. Added 47.0kWh but used 52.1kWh from the outlet: Efficiency is 90%. I set it to 20A out of the maximum allowable 48A for Model 3:
Charged from 37% to 100%. Added 47.0kWh but used 52.1kWh from the outlet: Efficiency is 90%. I set it to 20A out of the maximum allowable 48A for Model 3:
Tam
Well-Known Member
Um, OK I'll bite. So what does that have anything to do with figuring out how much it cost me to drive a mile? In an ICE car - it's simple, I drive 300 miles, put in 10 gallons @ $3.00/gallon or whatever, and it cost me $0.10 per mile. Done.
Not so easy in an EV when you charge at home, and there's other things pulling electricity at the same time you're charging so you can't just look at the meter. Early Tesla's reported only an 80% efficiency recharging. That's a pretty big number to ignore, so I was wondering what mine was. Plus there's vampire drain, about 3 miles per night in my car, and about 15 miles per day lost during the summer from cabin overheat (yes I can turn that off) when parked outside. All told, using 90% charging efficiency from @Tam's posts above, and my actual usage was 6,400 kWh over my first year (17,500 miles), when my car says it only used 5,100 kWh. Big deal? No, as that still comes out to only $.03 per mile - equivalent to getting 87 mpg using local regular gas prices here and 110 using premium (a fairer comparison given no 4 second 0-60 ICE car uses regular).
For fun, I then compared it to the Audi S7 I was also considering. Saving $2500/yr just in fuel! And that's without factoring in free supercharging or charging at work (both available, but I rarely use).
@Tam, thanks for sharing your data. 90% seems a fair number to use.
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