Can anyone answer this KWh discrepancies

[Turknhoff]

Hi can anyone answer this question for me, during the month of February from the very beginning to the end I have three different kWh usage readings as follows
Podpoint ev charger 237.8 kwh
Tesla phone app 222 kwh
Tesla trip A in car screen 129 kwh
Not a massive difference between the first two but when compared to what the car says it’s taken onboard there’s a huge drop of 100 kwh, I’m going to add the screenshots, would anybody be able to enlighten me please.
Thank you

 

[jjrandorin]

"Trip A" only shows energy used while driving. It has nothing to do with how much was actually put in the car, energy used while sitting, pre conditioning, etc.

What your charger puts out and what the car takes in is also subject to conversion in the car.

 

[MP3Mike]

The majority of the difference is likely because you have Sentry Mode enabled, and that energy usage doesn't get logged in a trip meter.

 

[Turknhoff]

Brilliant thank you very much, so the extra 100 kwh roughly would be me warming the car up and sentry mode ( I must say I have noticed sentry mode over the course of a day smashes the kw’s ) so if I hadn’t used anything other than the motors kWh to propel the car then I’d have saved 100kw
Also the cars trip display in a lot of ways is totally irrelevant as far as kw usage goes, to get the true picture you’d need to use the Tesla app for total kwh used.

 

[AlanSubie4Life]

Brilliant thank you very much, so the extra 100 kwh roughly would be me warming the car up and sentry mode ( I must say I have noticed sentry mode over the course of a day smashes the kw’s ) so if I hadn’t used anything other than the motors kWh to propel the car then I’d have saved 100kw
Also the cars trip display in a lot of ways is totally irrelevant as far as kw usage goes, to get the true picture you’d need to use the Tesla app for total kwh used.

Yes, mostly correct.

For such a short observation interval, with such small numbers involved, it is also important that the charge level of the car be identical at the beginning and end of the interval. Otherwise you may have added energy to the car that has not yet been used. (You could have had low SOC at beginning of observation interval, and high SOC at the end - your screen shows around 50%, so maximum error here would at most be 30kWh.)

But mostly it is all these other things mentioned above. Just was pointing out that this is important to account for with such measurements.

With 7-11kW charging, conversion losses are about 11-15%. Very low charge rates have higher overhead and much lower efficiency. These are accounted for in the Tesla app.

 

[Turknhoff]

Thank you for enlightening me, it seems my knowledge of ev’s is embarrassing, I thought charging at home on 7.2kw was the best way to charge these cars, we also have the solar panels so during the summer months it’ll mostly just be sitting on the driveway getting a trickle feed of juice, a lot of faff these electric cars so much easier to just pull up at the fuel station fill it up and forget about it for another month , between the solar panels and house battery plus buying the car I’d have been able to run a V8 for 30 years and still had change

 

[Rocky_H]

it seems my knowledge of ev’s is embarrassing, I thought charging at home on 7.2kw was the best way to charge these cars,

Well...yeah. No one said it wasn't. Any kind of regular AC charging around 6-12 kW or whatever is all great.

 

[AAKEE]

Sentry use about 200W, thats about 140 kWh in a month if the car was not used at all.
You can get an approximate calc of the the sentry use by 4 kWh x the number of days.

 

[Turknhoff]

That’s a crazy amount of kWh for a simple camera system, 4 kwh per day is insane. My last car had the blackvue system installed, just as good as sentry, it wouldn’t use 4kwh in a month let alone a day. This is probably why a lot only use it if they feel the car may be vulnerable, I’m in that category as it’s OFF most of the time, bit of a shame really to have this feature and not use it as intended because of the amount of power it saps. I wonder if anyone has ever put an aftermarket system in a Tesla to save on the juice and get away from sentry drainage? The really fail to understand why it uses so much power, I can run my home all evening on the house Solar battery which is 5.5kw, that’s tv’s and lights and everything else yet the Tesla will pull 4kwh a day

 

[AlanSubie4Life]

That’s a crazy amount of kWh for a simple camera system, 4 kwh per day is insane. My last car had the blackvue system installed, just as good as sentry, it wouldn’t use 4kwh in a month let alone a day. This is probably why a lot only use it if they feel the car may be vulnerable, I’m in that category as it’s OFF most of the time, bit of a shame really to have this feature and not use it as intended because of the amount of power it saps. I wonder if anyone has ever put an aftermarket system in a Tesla to save on the juice and get away from sentry drainage? The really fail to understand why it uses so much power, I can run my home all evening on the house Solar battery which is 5.5kw, that’s tv’s and lights and everything else yet the Tesla will pull 4kwh a day

It has nothing to do with the cameras really.

The computer is on, the DC-DC is on, etc. Cameras are likely a very small contributor.

It’s like they didn’t even think about having the ability to implement a lower power “awake” mode.

Oh well. Maybe a future vehicle.

 

[AAKEE]

Probably some computing power is needed to calcutste if things is a sentry event that need to be recorded and they probably only have one solution = to have the complete system on.

 

[Rocky_H]

That’s a crazy amount of kWh for a simple camera system, 4 kwh per day is insane. My last car had the blackvue system installed, just as good as sentry, it wouldn’t use 4kwh in a month let alone a day.

That's because the car was not built for that purpose unlike the Blackview. It's like if someone converted a car into an airplane and then complains that it doesn't perform well as an airplane. Right--because it wasn't made for that.

When the cars started coming out, they did NOT have this functionality. It was only because customers saw that there were cameras and asked Tesla to give the cars an option to do that, that they added this functionality. But running the cameras needs the computer, and the computer they have is a really high power massive processing beast. That was only meant to run when the car was on and in use, so it doesn't have an operating mode that is low power. It's either on and sucking juice, or it can turn off most of its functions and sleep, because it just wasn't designed to run cameras around the clock.

So a system that is built to be a sentry camera system will intentionally be made with a very small low power computer that uses low energy, but also can't do a lot more than run the cameras.

 

[3sr+buyer]

That’s a crazy amount of kWh for a simple camera system, 4 kwh per day is insane.

The issue is that Tesla cars need to be fully on for many functions, even if those functions by themselves do not require a lot of power.

 

[Turknhoff]

That's because the car was not built for that purpose unlike the Blackview. It's like if someone converted a car into an airplane and then complains that it doesn't perform well as an airplane. Right--because it wasn't made for that.

When the cars started coming out, they did NOT have this functionality. It was only because customers saw that there were cameras and asked Tesla to give the cars an option to do that, that they added this functionality. But running the cameras needs the computer, and the computer they have is a really high power massive processing beast. That was only meant to run when the car was on and in use, so it doesn't have an operating mode that is low power. It's either on and sucking juice, or it can turn off most of its functions and sleep, because it just wasn't designed to run cameras around the clock.

So a system that is built to be a sentry camera system will intentionally be made with a very small low power computer that uses low energy, but also can't do a lot more than run the cameras.

Yes I can see what your saying and the power that’s needed to run this sentry system, thank you for the explanation, I know it sounds like I’m rubbishing the system but my question was purely an inquisitive one, and now I have the answer