What's your Wh/mile efficiency from the wall?

[sandeen]

I got a Model 3 LR AWD at the end of 2018, and I've been tracking kWh used from the wall, based on the meter built into my EVSE. So far I'm at 2262kWh for 4164 miles driven (with only a very small amount of charging elsewhere). This gives me 543 Wh/mile, while the car odometer reports 1507kWh used while driving, for 363 Wh/mile. This is a very significant difference, almost 50% more from the wall (i.e. purchased) vs what the car reports as used while driving. To recap:

• Wall meter: 543 Wh/mile: 2262kWh for 4164 miles driven
• Car: 363 Wh/mile: 1507kWh for 4164 miles driven

Without getting into the why yet, I'm curious - for anyone else who is similarly able to track these numbers (either via something like TeslaFi, or a separately-metered EVSE) what is your Wh/mile efficiency from the wall (not what's reported by the car?)

Thanks,
-Eric

p.s. I think this is different from the "charging efficiency" threads - I know that some of the loss is due to charging efficiency, but I'm seeing a much bigger delta than what's expected for charging losses at this point.

 

[P85_DA]

I get about a 98% efficiency but my run is less than 3feet and I’m using #2 THWN wire on 100a circuit...number of factors play into ...ie what’s ur load when charging on house , what cable u using ..distance of run ..weather etc ..not sure this is an apples to apples comparison as most folks have differing setups

 

[sandeen]

To recap: I'm not asking about charging efficiency per se. I'm asking about net energy use efficiency in terms of Wh/mile - total kWh consumed from the wall divided by total miles driven.

 

[Funkmobile]

I got a Model 3 LR AWD at the end of 2018, and I've been tracking kWh used from the wall, based on the meter built into my EVSE. So far I'm at 2262kWh for 4164 miles driven (with only a very small amount of charging elsewhere). This gives me 543 Wh/mile, while the car odometer reports 1507kWh used while driving, for 363 Wh/mile. This is a very significant difference, almost 50% more from the wall (i.e. purchased) vs what the car reports as used while driving. To recap:

• Wall meter: 543 Wh/mile: 2262kWh for 4164 miles driven
• Car: 363 Wh/mile: 1507kWh for 4164 miles driven

Without getting into the why yet, I'm curious - for anyone else who is similarly able to track these numbers (either via something like TeslaFi, or a separately-metered EVSE) what is your Wh/mile efficiency from the wall (not what's reported by the car?)

Thanks,
-Eric

p.s. I think this is different from the "charging efficiency" threads - I know that some of the loss is due to charging efficiency, but I'm seeing a much bigger delta than what's expected for charging losses at this point.

Your charging efficiency greatly depends on the temperature of your battery and how deep your charge for. My efficiency can range anywhere from 65% to 95% depending on those factors.

 

[SSonnentag]

The less you drive your car and park at home, the higher your Wh/mile will be. Our X is parked most of the time, so its topping itself off every day or two. That's 2-3 kWh every couple of days with no miles being driven.

With that said, we don't meter the power going to the cars. However, using last month as an example, our solar power production was 1696 kWh and our total home power usage was 587 kWh (that includes both cars). So the parked X has little net effect in our electrical situation.

 

[sandeen]

FWIW, ours is a daily driver, 20-30 miles/day. Not a ton of preheating or sentry mode use.

 

[ewoodrick]

FWIW, ours is a daily driver, 20-30 miles/day. Not a ton of preheating or sentry mode use.

A suggestion is to not leave the car plugged in every day. Stay unplugged until you need it, say around 100 miles. See what happens to your numbers. I haven't plugged my car in for about a week and it is extremely happy.

Also, what does the consumption look like when the car is not actively charging? Is it using power?

And you are partially correct that you aren't looking for efficiency numbers, but a big portion of your number may be efficiency. And a portion is parasitic drain. Also, check the manufacturer documentation and see what the accuracy of your meter is. Is it +/- 10%??

 

[sandeen]

I'd like to get a sense of what's normal before speculating on causes...
It'd be great if anyone could just provide their numbers, either from teslafi ("total kwh used" on the charging summary, divided by odometer), or from the evse meter if you have one.

 

[P85_DA]

As was mentioned above your not accounting for phantom drain which is not going to he reported in your car ..u mention I use TeslaFi? If so there is a setting to put the car to sleep if that isn’t set than that can account for some drain ..sentry mode always on accounts for some ..u are in a cold climate ..battery heating accounts for some loss as well

 

[sandeen]

As was mentioned above your not accounting for phantom drain which is not going to he reported in your car

I understand all that. I'm asking.... begging ... to see what anyone else's actual numbers look like.

 

[willow_hiller]

A suggestion is to not leave the car plugged in every day. Stay unplugged until you need it, say around 100 miles. See what happens to your numbers. I haven't plugged my car in for about a week and it is extremely happy.

Isn't that the exact opposite of what the Model 3 owners manual says?

 

[seattlite2004]

Some data from the wall here: M3 MR vs Chevy Bolt (energy consumption)

 

[swaltner]

I keep track of my electricity using a TED 5000 system that has a set of CTs around the feed lines going to the EVSE in the garage. I fill in a spreadsheet on a month basis with my mileage and electricity expenses.

Pay particular attention to Home kWh + Supercharger kWh compared to Trip kWh (what the car's trip meter says it consumed) for a specific month. This is the energy lost in the transfer of energy into the battery, vampire drain, and pre heating/cooling of the cabin.

The Home Cost column is a little wonky because I have home solar and some months, I only pay for a portion of the electricity usage on the car. I'm still tracking the actual electricity that went to the EVSE and then the car battery though. Also, many of the Supercharger stops are estimates of the kWh since the ones in the MidWest seem to charge by the minute, not the kWh. Also note that the kWh in May/June of last year were a little strange. I purchased on May 31 and it took well into the morning on June 1 to recharge from the mini road-trip home. Also during June, the original software release didn't sleep very well, so there was pretty substantial vampire drain.

I put 58,250 miles on the 2013 Leaf SV before this. Used the same electricity monitor for that. Over that life, the efficiency at the main breaker panel was 3.56 miles/kWh or 281 Wh/mile. On a monthly basis (usually 1,000 miles of driving), I saw efficiency as high as 4.54 miles/kWh (220 Wh/mile) and as low as 2.77 miles/kWh (or 361 Wh/mile).

The displayed efficiency on the Model 3 is much better than the Leaf, but the Model 3 has much higher vampire drain, so in reality, the efficiency of the Model 3 is much lower. In addition, I judiciously use the phone app to heat/cool the Model 3, where I would only turn it the climate on a couple minutes ahead of getting in the car. Add to that that I lost the cellular service for the last year and a half of ownership on the Leaf (it came with a 2G cellular modem that I didn't want to pay to replace), so for 30% of its life, I couldn't remotely activate the climate control.

 

[sandeen]

Good info, thanks. So you're also seeing over 400Wh/mile in the cold months, with Feb approaching 500Wh/mile. OK, I don't seem to be an insane outlier ...

 

[AlanSubie4Life]

Good info, thanks. So you're also seeing over 400Wh/mile in the cold months, with Feb approaching 500Wh/mile. OK, I don't seem to be an insane outlier ...

Yeah, as you have seen in the other thread, you’re not an outlier.

There is another Tesla forum where a guy did some very detailed long term measurements, and in the end, if you want a basic rule of thumb, this is what he provided...It is linked to somewhere around here but don’t remember exact forum:

Displayed value in car * 1.2 for warm months. (This is probably 9-10 months in Southern California - might be just 6 months elsewhere)

Displayed value in car * 1.4 for really cold months.

This is for a typical 12k miles per year - the mileage matters due to vampire drain which is a little less than a 10% adder (included in the scaling factors above) for this annual mileage assumption.

Obviously just a rough rule of thumb, and specific user behaviors could easily skew it one way or the other, and the exact degree of cold matters too of course. Just a rough estimate for budgeting purposes.

 

[BioSehnsucht]

Charge speeds matter, too. There's some overhead in operating the inverter and heating/cooling systems and so on, and the longer the car is charging the more of these fixed-per-unit-time power costs come into play. Charging at 120V 12A should be much less efficient than 240V 48A due to this.

 

[edigest]

I understand all that. I'm asking.... begging ... to see what anyone else's actual numbers look like.

Climate seems to be a significant factor. I'm in a warm climate and my numbers are improving marginally as the weather warms up, but through 100 local trips over the past couple months, I totaled up 589 miles and added 147.6 kWh. That averages out to 246.8 Wh/mile.

I'm currently charging with 120V averaging about 78% efficiency so my Wh/mi is closer to 300 when factoring in the electrons used by the charger.