Something’s off.

It’s telling me I charged 2811 kWh but consumed 2133 kWh.

But I didn’t know about this summary - thanks for posting it so I could be inspired to look for mine.

 

Crazy isn’t it ? How do you normally charge ? I can cofirm through my Tesla gateway that the “charged” amount is accurate but where the hell did almost 1 megawatt go?!

 

I use a combination of mostly at work L2 chargers and DCFC at Electrify America.

 

@24ixmax @LuisBoston Charging losses

"ADAC in Germany conducted a charging test with a new BMW iX, which was hooked up to a 22 kW (16 amp) AC wall charger with an ambient temperature of 73.4°F (23°C).

It found that to charge the iX’s 105.2 kWh battery pack, it actually took around 125.2 kWh. That equates to about 20 kWh (or 20 percent) losses, which seems like a lot, but it’s not far from the average loss expected when charging EVs, which is around 15 percent.

Another example of this being documented can be found in Tesla’s certification documents filed with the EPA, as quoted by Car and Driver. The data there shows that adding a little over 81 kWh to a Model Y Performance’s completely depleted battery pack via a 240-volt Level 2 charger actually required 92.2 kWh of electricity, which equates to a 14 percent loss.

Basically, the main pieces that affect charging losses when using an AC (Level 1 or Level 2) charger are the EV’s onboard AC-to-DC converter, the charger, and charging cable, the EV’s battery (and whether it has thermal management), and the charging power. Some of the electricity lost is simply attributed to what is known as 'transmission losses,' some of it is lost to heat, and some is used to keep the battery temperature optimal during charging."

 

@24ixmax @LuisBoston Charging losses

"ADAC in Germany conducted a charging test with a new BMW iX, which was hooked up to a 22 kW (16 amp) AC wall charger with an ambient temperature of 73.4°F (23°C).

It found that to charge the iX’s 105.2 kWh battery pack, it actually took around 125.2 kWh. That equates to about 20 kWh (or 20 percent) losses, which seems like a lot, but it’s not far from the average loss expected when charging EVs, which is around 15 percent.

Another example of this being documented can be found in Tesla’s certification documents filed with the EPA, as quoted by Car and Driver. The data there shows that adding a little over 81 kWh to a Model Y Performance’s completely depleted battery pack via a 240-volt Level 2 charger actually required 92.2 kWh of electricity, which equates to a 14 percent loss.

Basically, the main pieces that affect charging losses when using an AC (Level 1 or Level 2) charger are the EV’s onboard AC-to-DC converter, the charger, and charging cable, the EV’s battery (and whether it has thermal management), and the charging power. Some of the electricity lost is simply attributed to what is known as 'transmission losses,' some of it is lost to heat, and some is used to keep the battery temperature optimal during charging."

Wow that’s pretty wild. This basically means the consumption needs to be bumped up by 20% in order to remain accurate when it comes to actually figuring out driving costs.

 

This is kinda old news, but yours still looks really high. What is the charge rate of your home charger? Some of the EPA ratings include charging losses. The lower the rate of charge, the higher the % losses. There are material fixed losses during a charge.

Mine was 2,529 kWh consumed to 2,949 kWh charged, so 17% losses. I charge almost entirely at 11 kWh, so relatively high percent losses. I am curious how that compares to cars charged DCFC often and to cars that charge slower, like 7 kW.

 

How is mine really high ? 17 or 20% pretty much similar. That’s a deep double digit loss of charge that I was not aware of when purchasing this car. Yea blah blah could have done even more research I suppose.
I charge 90% of the time at L2 at home or work. Home is at 40amp, work at 32 so 9.6kw/hr or 6.6kw/hr

 

I have a 21.6% charging loss then, considering there’s about 70 kWh in the battery right now.

Of 2811 kWh charged, 1337 kWh were at Electrify America. So safe to assume ~50% DCFC for me.

 

Wow that’s a massive added cost

 

I don’t think that the “total consumption” includes the energy used to precondition the car prior to driving, so if you use 1kWh to warm (or cool) the car before each journey that adds up to a large amount of energy that is not included in the journey statistics.

 

I do not on the regular. For example there are months where I don’t use heating or cooling here in California and the discrepancy remains

 

This is mine. I charge mostly level 2 and i throttle the speed to 9.6kw. I think the 10.5% loss is normal and i rarely precondition the car.

 

Where is your total “used”?

 

Hold on - there’s another profile on my car. Does the total used include that drivers profile???

I cannot see their trip statistics in my profile. They drive in their profile maybe 5-10% of the time.

I’ll need to look it up later.

 

Hold on - there’s another profile on my car. Does the total used include that drivers profile???

I cannot see their trip statistics in my profile. They drive in their profile maybe 5-10 of the time.

I’ll need to look it up later.

this is main thing i dislike about the bmw app as you cannot see your total consumption for the whole vehicle.

 

December, which was 82% DCFC due to my road trip:
Total Charged: 1,553 kWh
Total Consumption: 1,410.5 kWh
Charging Overhead: 10.1%

All of 2024 (51% AC, 49% DCFC):
Total Charged: 6,688 kWh
Total Consumption: 5,785.8 kWh
Charging Overhead: 15.6%

Half of the DCFC in 2024 were in peak summer, the other half in winter (temps from 40s to 60s). AC charging is done all year round, as needed, and typically at 48A.

I believe the EPA's MPGe and energy consumption ratings as stated on the Monroney sticker factor such overhead losses. For example, my sticker shows consumption at 39 kWh/100 mi which equates to 390 Wh/mi. However, the 315 mile EPA range rating based on 106 kWh usable pack is more like 336 wh/mi. The difference is 16% and aligns with expected losses.

One always has to expect losses to resistance and overhead to cooling and charging systems in the vehicle. When calculating economics of charging, one should factor in these losses. Most are unaware that this information is available on the Monroney with the application of a little math.

 

Maybe there are three high-level break points around expected charging losses†:

• Level 1 - 20%
• Level 2 - 15%
• DCFC - 10%

†These are not meant to be precision or absolutes, just rough order of magnitude expectations for the typical charge rates we encounter. Plus, there are probably some additional modifiers driven by ambient and battery temperature at time of charge.

 

That makes a lot of sense. The least efficient method to charge one's vehicle is L1. There is a certain amount of overhead incurred to charge one's vehicle because components in the charging system, like inverters, charge port, computer, sensors, cooling, etc. have to be energized. Losses don't stop at the charge port, they continue throughout the system.

I've read in various Tesla threads that 48A tends to be the sweet swot for efficient charging at home. I can imagine the iX is approximately the same in this regard. I have yet to hear my iX cooling fan ramp up at 48A. In fact, it sounds the same as when I charge at 16A.

 

Hi
There is something seriously wrong with the charging data in the app.
From our annual summary - we have driven 17241 km in 2024 and consumed 4526.7 kWh
The charging screen shows that we have charged 8006 kWh in 2024.
98% of our charging was done at home using our Tesla 11kw wall box

There is no way that we have charged nearly double what we have consumed!
Cheers
Steve

 

are you adding kwhs consumed among all user profiles? the app only shows consumption for 1 profile.

 

Since acquiring my iX every charge session has been recorded: almost all AC charging (78% of all charging) has been done at home so Home Assistant has queried the charger (a Zappi) for the charge added in session; for DC charging it's a matter of reconciling kWh from apps/invoices.

The AC charging depends on the EVSE internal CT, which is consistent with grid CT readings and can be assumed to be >99% accurate.

The HPDC charging (22% of all charging) is dependent on the provider, but nowadays the charge added in session is to 3 decimal places and like an AC session is consistent with the vehicle's recorded charge. (One may assume that HPDC stations have a good degree of accuracy in measuring power and energy as the business model largely depends on getting this stuff right). Charge stations used mainly include Tesla, Fuuse, Gridserve, Fastned, CPS.

The magic numbers obtained using this methodology over about 8,000 miles are:
AC charge loss = 14.04%
HPDC charge loss = 11.44%

The graph plots of charge sessions based on kWh per percent battery are remarkably linear, and the AC and HPDC lines are very close together. There will be some error in the data acquisition due to the vehicle/app only reporting integer percent numbers: so consequently the higher charge added sessions are somewhat more reliable from a data accuracy perspective.

An observation regarding reported battery percentage and miles possible: it seems remarkably linear. The i3 is largely similar but goes to pieces below 25% remaining; the iX feels really consistent in terms of miles possible per x% battery.

Everybody's experience will be slightly different based on battery size, weather, cables, connectors, EVSE efficiency, battery health, CCU health, etc. However it is hoped that these data points are useful to some folk who are interested in this type of - frankly - geekiness

 

Ability to charge at home with solar is the gold standard!

 

Absolutely, and even better, if you have solar and are retired, as I am, because then you can do it before the sun sets and shortly after the sun comes up, before getting up yourself.

 

Fight for net metering in your country so that the time of day doesn't matter. It's all about end of the billing month tallies!

 

From "Go-E" in the UK:

You can use the data provided by reputable testing organizations.


For instance, ADAC has conducted an ecotest using the same 22 kW wallbox (AC) and the same ambient conditions (23°C) to discover the charging loss. The charging losses turned out to be considerable.


For instance, the result shows that 125.2 kWh must be charged to fill the 105 kWh battery of the BMW iX. The situation is no better in the case of the less expensive Jaguar i-Pace - 100.8 to 90 kWh.

 

This is spot on Ty.