Charging efficiency question

[Sean.]

I believe it says it I am just not convinced its right since I can't figure out where its coming from and I am like that
If it matches the figure you are billed for at a non Tesla DC charger then fair enough I guess its right.

I might ping a note to the app developer to ask where the value is pulled (or how it’s calculated).

The support FAQ doesn’t go into detail.

 

[Sean.]

I've got a Gen2 Tesla wall connector metered through a Crompton DRS-100-3P so later in the morning (if I remember) I'll have a look at the voltage its reporting across the various phases, compared to car and app. when its goes on charge.

Off charge (line to neutral) voltages:


On charge (line to neutral) voltages:


On charge current per phase:


On charge power per phase:


Tesla app during charge:

 

[dafish]

I was SO confused. 3phase with 240 to neutral. Had me for a moment there.

US is 120V leg to <> N, 240 L <>L when are 1 phase, and, as I recall, 208 leg to leg at 3p.

 

[Sean.]

I was SO confused. 3phase with 240 to neutral. Had me for a moment there.

US is 120V leg to <> N, 240 L <>L when are 1 phase, and, as I recall, 208 leg to leg at 3p.

Our line to neutral voltage is (nominal) 240 volts. On three-phase its 415V line to line. Same as Australia, including frequency.

 

[dafish]

Yea, I figured it out after looking at your readings. which is what confused me at first.

 

[Sean.]

I believe that to be the case yes

The added yes I agree that would be what was added to the battery. Probably comes from the "charge_energy_added" value in the charge state API.

but as for the 73.01 I have no idea where that comes from and I don't know of anything in the API that equates to the AC provided by a supercharger so I am not convinced it is what you think it is.

So on AC charge tonight by Crompton DRS-100 meter, the charge used was 64.26 kWh. According to the Tessie App it used 64.84 kWh - so. the Tessie app was slightly pessimististic, but within 1%.

The "Added" value was 60.43 kWh according to the app - which is 93% (actually 94% using actual metered value) efficient.

 

[Jason71]

So on AC charge tonight by Crompton DRS-100 meter, the charge used was 64.26 kWh. According to the Tessie App it used 64.84 kWh - so. the Tessie app was slightly pessimististic, but within 1%.

The "Added" value was 60.43 kWh according to the app - which is 93% (actually 94% using actual metered value) efficient.

An AC charger is basically a switch. The losses in AC Charging are mostly in the car so i accept the car would have a pretty accurate view on that

 

[GeorgeSymonds]

I believe that to be the case yes

The added yes I agree that would be what was added to the battery. Probably comes from the "charge_energy_added" value in the charge state API.

but as for the 73.01 I have no idea where that comes from and I don't know of anything in the API that equates to the AC provided by a supercharger so I am not convinced it is what you think it is.

I’ve been sceptical about them for a while. Their battery health chart.. there’s nothing really in the API which tells you whether you have say a 75, 79 or 82 kWh battery in a LR. When I look at my data it just says I have a 74d when I have a 79kwh battery on my MY and it also said I had a 74d when I had a 75kwh battery in our older M3. They can guess, and a lot of the time it might be near enough, but reliable? They might be trying to work out efficiency by converting miles added to energy added using the rated energy consumption, and comparing that to energy added, but that’s assuming they know what every figure really includes. Still, it’s got people talking about them which was probably their intention.

 

[Jason71]

I’ve been sceptical about them for a while. Their battery health chart.. there’s nothing really in the API which tells you whether you have say a 75, 79 or 82 kWh battery in a LR. When I look at my data it just says I have a 74d when I have a 79kwh battery on my MY and it also said I had a 74d when I had a 75kwh battery in our older M3. They can guess, and a lot of the time it might be near enough, but reliable? They might be trying to work out efficiency by converting miles added to energy added using the rated energy consumption, and comparing that to energy added, but that’s assuming they know what every figure really includes. Still, it’s got people talking about them which was probably their intention.

I think the idea that there is no such thing as bad publicity died with Elon Musks purchase of Twitter TBH

 

[GeorgeSymonds]

I think the idea that there is no such thing as bad publicity died with Elon Musks purchase of Twitter TBH

You make a good point

In the Tesla world I’m 100% certain that if you say anything with the illusion of authority, people will believe it…

 

[GSP]

I think the idea that there is no such thing as bad publicity died with Elon Musks purchase of Twitter TBH

LOL, for sure.

However that saying does mostly end up being true. For example Tesla Model Y and 3 were the two best selling vehicles in Blue State California last year, outselling Honda Civic, Toyota Camry, and Ford F-150, and every other car and truck. Even bad publicity gets the word out to the general public that there is such a thing as a Tesla, with zero advertising spend. Once people are aware there is such a thing, they might research it next time they buy a car. Hard to resist Tesla once you compare to anything else.

GSP

 

[Jason71]

LOL, for sure.

However that saying does mostly end up being true. For example Tesla Model Y and 3 were the two best selling vehicles in Blue State California last year, outselling Honda Civic, Toyota Camry, and Ford F-150, and every other car and truck. Even bad publicity gets the word out to the general public that there is such a thing as a Tesla, with zero advertising spend. Once people are aware there is such a thing, they might research it next time they buy a car. Hard to resist Tesla once you compare to anything else.

GSP

$44 billion is a pretty hefty ad spend in my book!