Model Y charge stats discrepancy

[anarchi]

I have had my Model Y LR for just under four months now and have driven just over 2,200 miles. During this time I have charged the car from three sources: My office (Shell Recharge), Home (Hypervolt) and Tesla superchargers. According to these three sources I have charged the car with 819KwH. According to the lifetime trip meter on the Tesla (never reset), I have used 647KwH. The fact that the car is currently at 80% will account for some of this discrepancy, but not the full 172KwH. The trip screen in the car tells me that my average wH/mile is 286, whereas my calculation has it at closer to 360! I notice that charge amounts for the superchargers and shown in the car are always whole numbers whereas Shell and Hypervolt show decimals, but again rounding is not enough to account for the difference.

Is this a well-known thing? And if so, how do I figure my real consumption?

 

[OfficialMark_H]

Sentry mode will take a bit of power every day if you use that?

 

[anarchi]

Sentry mode will take a bit of power every day if you use that?

Thanks, but it's not the amount being used each day, it's the charge figures that are off. I have noticed that the number of KwH charged according to the Hypervolt and Shell Recharge apps is about 10% higher than the corresponding figure from the car. If I carry this across the board for those charging sources, then it makes up some of the difference, but not all.

 

[TheRealWatto]

Tesla reporting the amount of KWh that made it into the battery vs. the chargers recording what was delivered? Some will be lost to heating or cooling the battery, the cabin, etc.

 

[Matt Porter]

What @TheRealWatto said.

This article suggests about a 10% loss in fast charging.

Tesla Model 3 Charging Losses Explained

We examine the YouTube video from the channel, State Of Charge, that analyzes and explains charging losses when DC fast charging a 2021 Tesla Model 3.

insideevs.com

 

[ben_c]

Sentry mode will take a bit of power every day if you use that?

This

Trip meter only logs energy used when moving. When in park / sentry you’ll be using electrons not counted in the trip meter.

 

[anarchi]

This

Trip meter only logs energy used when moving. When in park / sentry you’ll be using electrons not counted in the trip meter.

Thank you for the interesting replies. What I take from this is:

The difference between what the Hypervolt and Shell Recharge charge points tell me and what the car says is about 10% and is probably due to the difference between what is pushed and what is accepted (and probably includes heat loss among other things).

A further 10 to 15% is then lost through sentry mode and the typical 1% per day wind down.

So the amount of electricity you put into the Tesla is about 20 to 25% more than the amount reported by the car in the trip meter.

That changes the cost/mile calculation, but it's very helpful, thank you.

 

[Jason71]

Thank you for the interesting replies. What I take from this is:

The difference between what the Hypervolt and Shell Recharge charge points tell me and what the car says is about 10% and is probably due to the difference between what is pushed and what is accepted (and probably includes heat loss among other things).

A further 10 to 15% is then lost through sentry mode and the typical 1% per day wind down.

So the amount of electricity you put into the Tesla is about 20 to 25% more than the amount reported by the car in the trip meter.

That changes the cost/mile calculation, but it's very helpful, thank you.

You are correct and it is something I am always banging on about here. It does change the cost calculation and it often gets ignored. When people talk about wh/m that number is only useful for calculating range between charges and in my experience if you want the true cost you need to add 30-35% This is based on a 4 month period when I first got mine which was winter so preheating in addition to what you have listed.

Interestingly the Tesla superchargers are metered by the car so the car reports what it receives in DC. Opinion varies as to whether that means Free HVAC while supercharging or if that is counted. but what is not in dispute is everyone else chargers for the AC consumed by the charger which means when looking at SuC prices you need to add 10% onto everyone else's to make them equivalent.

 

[kelvin 660]

I've found that ~8% is lost in the ac to dc conversion (when charging from ac) and ~8% filling the battery and another 8% in emptying the battery, making around 24% losses when compared to the car trip meter. Add in sentry and other losses and you will be nearer 28%

In my case, 2,077 reported by car trip meter and 2,655 kWh actually supplied to the car. And yes, it does make a difference to the cost per mile but it's still only a 1/10th of the price of petrol...

 

[bp1000]

I've found that ~8% is lost in the ac to dc conversion (when charging from ac) and ~8% filling the battery and another 8% in emptying the battery, making around 24% losses when compared to the car trip meter. Add in sentry and other losses and you will be nearer 28%

In my case, 2,077 reported by car trip meter and 2,655 kWh actually supplied to the car. And yes, it does make a difference to the cost per mile but it's still only a 1/10th of the price of petrol...

This pretty much nails it and has been my experience driving a model s since 2015.

The trip computer only tells you the energy consumed whilst driving.

As kelvin mentioned, energy loss as heat is a big factor and the car running auxiliary, ac and battery management is the rest.

 

[anarchi]

This pretty much nails it and has been my experience driving a model s since 2015.

The trip computer only tells you the energy consumed whilst driving.

As kelvin mentioned, energy loss as heat is a big factor and the car running auxiliary, ac and battery management is the rest.

My initial post was a query not a complaint. Even with the additional electricity and my heavy foot it still comes out at less than 9p per mile (total charge costs including superchargers). I haven't had that price since a Toyota Starlet in 2003. I just like to keep track of all costs and wanted to make sure I hadn't missed something.