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gg_got_a_tesla
Model S: VIN 65513, Model 3: VIN 1913
Jerry, can you please share the 30-mile energy graph from one of these days that you do your 25-mile commute at 200 Wh/mile?
Would love to get a feel for your speed curve too over that distance.
How are these numbers even humanly possible?!
Would love to get a feel for your speed curve too over that distance.
How are these numbers even humanly possible?!
His gauge is broken. See how it's stuck at like 1 kW? Easy to get those numbers with gauges like that.How are these numbers even humanly possible?!
Al Sherman
It's about THIS car.
My July numbers.
Indiana/P85/21 inch
427.2 mi
128.9 kWh
302 Wh/mi
Lifetime:
3425.3 mi
1067.9 kWh
311Wh/mi
Indiana/P85/21 inch
427.2 mi
128.9 kWh
302 Wh/mi
Lifetime:
3425.3 mi
1067.9 kWh
311Wh/mi
LOL!!!
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That's the only way I could see myself doing that kind of efficiency also. My feeling for every day driving is drive like you normally would drive and then look at your number if you wish (unless you're on a huge road trip, etc.).
mknox
Well-Known Member
Charger and Vampire Losses as High as 29%
So I record and reset my Trip A odometer at the beginning of every month (and leave Trip B showing "lifetime" stats) plus I record the values from my dedicated EV circuit meter over the same time period.
I've tried to compare what the car is telling me vs. what I see from the meter, but my numbers are usually skewed due to the fact that I'll do some "opportunity charging" from time to time and don't have data for those kWhs.
Well, in July it just so happened that the only outside of home charging I did was at a ChargePoint station where I was able to log on and see how much I'd added to the car. Finally, I have all the numbers. Here they are for July:
Distance: 1,258.6 miles
kWh from Car: 384.3
kWh from Sub-Meter: 469.099
kWh from ChargePoint: 25.751
So, the car is telling me 384.3 kWh while I know I put 469.099 + 25.751 = 494.85 kWh into the car.
This represents an unaccounted for 110.6 kWh of electricity, or a 29% increase over what the car is reporting.
Looking at it another way, the car reported I was getting 305 wh/mi, but based on the electricity I put into the car, it's really 393 wh/mi.
I'm not sure what conclusions to draw from all of this other than to say that the car's trip meters clearly do not represent how much electricity the car really uses, and by a significant margin.
So I record and reset my Trip A odometer at the beginning of every month (and leave Trip B showing "lifetime" stats) plus I record the values from my dedicated EV circuit meter over the same time period.
I've tried to compare what the car is telling me vs. what I see from the meter, but my numbers are usually skewed due to the fact that I'll do some "opportunity charging" from time to time and don't have data for those kWhs.
Well, in July it just so happened that the only outside of home charging I did was at a ChargePoint station where I was able to log on and see how much I'd added to the car. Finally, I have all the numbers. Here they are for July:
Distance: 1,258.6 miles
kWh from Car: 384.3
kWh from Sub-Meter: 469.099
kWh from ChargePoint: 25.751
So, the car is telling me 384.3 kWh while I know I put 469.099 + 25.751 = 494.85 kWh into the car.
This represents an unaccounted for 110.6 kWh of electricity, or a 29% increase over what the car is reporting.
Looking at it another way, the car reported I was getting 305 wh/mi, but based on the electricity I put into the car, it's really 393 wh/mi.
I'm not sure what conclusions to draw from all of this other than to say that the car's trip meters clearly do not represent how much electricity the car really uses, and by a significant margin.
deonb
Active Member
How are these numbers even humanly possible?!
Maybe his wife owns a flatbed for the hills.
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This is over a month right? So that's 3.6kWh per day, or about 12 miles of range per day loss.
That's consistent with daily vampire loss numbers.
Good news is that number should drop significantly by the end of the year.
mknox
Well-Known Member
That's a piece of it. I was away for about two weeks and observed from my meter logs that the car "topped itself up" to the tune of exactly 5 kWh every other day. That's 2.5 kWh / day in standby losses.
I think this'll be exacerbated in the colder winter months and certainly pre-conditioning the car from shore power will add to it (just as using remote start on an ICE would use more gas).
I guess my point is that the dash displays are a bit disingenuous. I would prefer if the car measured the amount of power coming in through the charge port and used that in its calculations. What matters to me is how much I put in to the car (just as what used to matter is how much gas I used to put in my ICE).
Owner
Active Member
I have the same problem with PG&E. With solar you can't get a real measurement of how much you have used during the year or how much you have produced. You only get how much you have net used. Took me a lot of data crunching to figure out how much energy my Roadster used with year to year comparisons pre Roadster, post Roadster, that of course were only reasonably accurate.
mknox
Well-Known Member
Yes. You really need sub-meters to be able to work these things out accurately. I assume your solar is simple net metering where the solar offsets your home's consumption, so yes, the utility meter will only show you the net difference.
You might want to consider something like the TED to help you understand what's going on in your home and with your vehicle.
From a cost perspective, this is indeed preferred.
EVs (at least Tesla EVs so far) are introducing something different from ICE vehicles -- namely that your fuel/energy can evaporate/decay over time just from sitting idle. As such, the "fuel/energy consumption while driving" and "fuel/energy consumption over time" diverge and you have two metrics of interest.
The first is the cost one as noted above -- and Tesla doesn't display this in the Trip UI.
The second is the consumption rate for driving -- and Tesla does display this in the Trip UI.
I don't think they should remove or adjust the second, but rather provide new UI for the first.
I don't consider Tesla's reporting disingenuous, I just think it's showing a different metric than you want.
There's also a 3rd metric -- that I don't expect them to ever implement -- actual energy cost including wire losses from the wall to the vehicle.
mknox
Well-Known Member
Fair enough, but I suspect the casual user isn't aware of all this and is assuming that if the car reports xyz kWh in a given period of time, then that's how much electricity they've paid for. Or to look at it another way, if someone wants to size a solar installation to cover their car's power requirement, they'd better add about 30% to what the Trip Meters are reporting.
I'm not sure, but I thought some Roadster owners reported that their cars could show input power.
deonb
Active Member
Still... the far more important metric is "how far can I get with a given charge". By watching wh/mi over time you get a sense of how the car performs on a given road at a given speed, and vampire losses are almost irrelevant on the road. After a while you can predict what your wh/mi would be for a given trip, which helps in planning.
If non-road usage are included in the kWh usage number it would render this very important metric fairly meaningless. You'd see 6000 wh/m by driving to the grocery store after a weekend stop.
I think if someone really care about every kWh that is poured into the battery, you'll also care about the power loss in the cable and UMC as well. In that case what you need is a second meter - nothing the car can do will help with that.
I believe this TED unit would help you.
Amazon.com: Energy, Inc. 5000-C TED (The Energy Detective) 5000: Home Improvement
TXjak
Owner/Investor/Advocate
I suspect that another piece of it has to do with how efficiently the charger(s) convert AC to DC. I installed a kWh meter in line with my 14-50 and have been recording data for a while. It should be interesting to see how the usage changes when we get the update to cut the vampire loads.
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