Home Charger power expectations/reporting

[ciaranob]

Had a moment between festivities and wanted to throw this out there (I do actually have a life ):

I have a ChargePoint HomeFlex at home here in the US which is hardwired (in a dedicated 100 AMP garage panel) to a 60 Amp breaker (up to 48 Amp max available to charge), thus have the potential to see 11.3 kWs at the car.

I need to confirm what I can draw in off-peak hours (if at all relevant - not specifically relevant to me as I am on a fixed rate plan) should that be different but was curious to hear from the electricians/electrical engineers amongst us as to whether there might be any limitation in respect my setup in reaching the max. 11.3Kws?

In the pics below I am charging in the afternoon here in Houston, house load is low (e.g. no draw from heat nor from AC systems etc) but I have yet to see the charger deliver more than 10.5 KWs.

The ChargePoint app references 11.35 kW for a typical 2020 Taycan but my in car screens indicate 10.4 to 10.5 max. That said, if I am truly getting 3.69 kW per 20 mins as indicted in the ChargePoint app then that of course is just over 11 kW per hour at the car which is diff to what the car is reporting - call me confused

Tend to believe what the car is saying and TBH, I actually am quite satisfied with 10.5kW but here to be educated

Cheers, C.

PS: See Pic attached re one minor annoying "PCM feature" is that I cannot find anywhere (nor could the SA) where I can change the KM to Miles as it should be reading in the PCM main screen - lower screen shows the correct unit - went to system settings etc. etc. - tried toggling things on/off - no fix).

Here is what the car reports (have all timers profiles off here as want to set a 100% baseline charge and see how that changes in next month of driving) - 10.4kW at car (also the KM error in main screen):

Here is what the ChargePoint screen is showing (3.69 kw per 20mins is just over 11 kw per hour):

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[yman182]

That is about right. You will see around a 10% loss from what the charger is delivering to what can be used. I have a 9.6kw (50A charger) and see about 8.65 delivered at the car.

there is a good video on insideEVs that explains this.

 

[ciaranob]

That is about right. You will see around a 10% loss from what the charger is delivering to what can be used. I have a 9.6kw (50A charger) and see about 8.65 delivered at the car.

there is a good video on insideEVs that explains this.

Ah - that makes sense (cable loses etc) - would be good if the charger would calculate to offset this to give a more real world delivery but I guess the car does that for us

 

[Jhenson29]

Ah - that makes sense (cable loses etc) - would be good if the charger would calculate to offset this to give a more real world delivery but I guess the car does that for us

It’s giving the actual delivery to the battery, which is typically more useful as that will tell you the actual recharging rate.

 

[ciaranob]

It’s giving the actual delivery to the battery, which is typically more useful as that will tell you the actual recharging rate.

Are you referencing the car's reported rate (10.5) or the EVSE's rate (11+) - assume the former?

The car charged from an SOC of 79% to 100% in almost exactly 2 hours (1:55PM to 3:56 PM) - outside temp ca. 80F - it of course slowed down significantly when closer to 100% (to less than 7kW per hour) - guessing at these rates I'd expect a charge from 0 to 100 (a situation I'd never allow to happen!) to range from between 8+ to 10 hours?

I've only got 117 mi on the odometer and at it's first 100% charge its reporting 242 mile range - seems pretty solid to me as I would hope after doing a better mix of longer range drives and around town trips the system will better calibrate and hopefully predict more range - requires me to have patience, and my other half laughs

Garage temp reached 83F near end.

First 100% charge after only first 117 miles of mostly around town short trips.

 

[Jhenson29]

Are you referencing the car's reported rate (10.5) or the EVSE's rate (11+) - assume the former?

The car. I understand the car’s rate to be delivery to the battery (GTK refers to it as “current charging power”).

guessing at these rates I'd expect a charge from 0 to 100 (a situation I'd never allow to happen!) to range from between 8+ to 10 hours?

Yes, 0-100% probably approx 8hr.

 

[Tooney]

Garage temp reached 83F near end.

Garage temp 83F / 28.3C. In December. Ugh.

 

[ciaranob]

Garage temp 83F / 28.3C. In December. Ugh.

Yeah we have a week plus of weird weather but minimal humidity and most of day actually super pleasant

 

[daveo4EV]

10.4 kW is about what I see off my 48 amp EVSE according to the in vehicle charging UI…

 

[ciaranob]

10.4 kW is about what I see off my 48 amp EVSE according to the in vehicle charging UI…

Thx , yes indeed - too much Xmas spirit perhaps (!!), as the losses through the cable etc., as pointed out by @yman182, make complete sense - clearly had not thought that through

 

[Jhenson29]

Thx , yes indeed - too much Xmas spirit perhaps (!!), as the losses through the cable etc., as pointed out by @yman182, make complete sense - clearly had not thought that through

You have to squeezes the cable to push the energy through (like a tube of toothpaste) to get the full 11kW. ?

 

[Klepper]

Are you referencing the car's reported rate (10.5) or the EVSE's rate (11+) - assume the former?

The car charged from an SOC of 79% to 100% in almost exactly 2 hours (1:55PM to 3:56 PM) - outside temp ca. 80F - it of course slowed down significantly when closer to 100% (to less than 7kW per hour) - guessing at these rates I'd expect a charge from 0 to 100 (a situation I'd never allow to happen!) to range from between 8+ to 10 hours?

I've only got 117 mi on the odometer and at it's first 100% charge its reporting 242 mile range - seems pretty solid to me as I would hope after doing a better mix of longer range drives and around town trips the system will better calibrate and hopefully predict more range - requires me to have patience, and my other half laughs

Garage temp reached 83F near end.

First 100% charge after only first 117 miles of mostly around town short trips.

Only 117 miles on it so far? Quit typing here and get out and drive it!!

 

[02bluesuperroo]

A little different setup for me but I figured it still fits the thread topic. I have the 19.2kw charger spec'd and I have a Wall Wattz WattZilla 75-amp EVSE that is hard-wired to a 100amp breaker. The most I see is 16.4 kw charging speed, which I'm very happy with, even though in theory it could get into the 17s.

BTW, I also have that stupid problem where it shows my range in KM on the on the main screen even though the number is in miles and all the other labels around the car say miles.

 

[XKSS]

Mine does that miles/ KM too - must ask the dealer?

 

[caslca]

Had a moment between festivities and wanted to throw this out there (I do actually have a life ):

I have a ChargePoint HomeFlex at home here in the US which is hardwired (in a dedicated 100 AMP garage panel) to a 60 Amp breaker (up to 48 Amp max available to charge), thus have the potential to see 11.3 kWs at the car.

I need to confirm what I can draw in off-peak hours (if at all relevant - not specifically relevant to me as I am on a fixed rate plan) should that be different but was curious to hear from the electricians/electrical engineers amongst us as to whether there might be any limitation in respect my setup in reaching the max. 11.3Kws?

In the pics below I am charging in the afternoon here in Houston, house load is low (e.g. no draw from heat nor from AC systems etc) but I have yet to see the charger deliver more than 10.5 KWs.

The ChargePoint app references 11.35 kW for a typical 2020 Taycan but my in car screens indicate 10.4 to 10.5 max. That said, if I am truly getting 3.69 kW per 20 mins as indicted in the ChargePoint app then that of course is just over 11 kW per hour at the car which is diff to what the car is reporting - call me confused

Tend to believe what the car is saying and TBH, I actually am quite satisfied with 10.5kW but here to be educated

Cheers, C.

PS: See Pic attached re one minor annoying "PCM feature" is that I cannot find anywhere (nor could the SA) where I can change the KM to Miles as it should be reading in the PCM main screen - lower screen shows the correct unit - went to system settings etc. etc. - tried toggling things on/off - no fix).

Here is what the car reports (have all timers profiles off here as want to set a 100% baseline charge and see how that changes in next month of driving) - 10.4kW at car (also the KM error in main screen):

Here is what the ChargePoint screen is showing (3.69 kw per 20mins is just over 11 kw per hour):

One more thing to OP: The power delivery is calculated in Watts and is = Amperes*Volts (W=A*V). US electrical systems are 230-240V depending on your particular provider. At 48A, this gives you power delivery range of 11040W to 11520W (i.e. 0.5KW difference). You can use a voltmeter on your master panel to see exactly how much voltage you're getting. So keep in mind, this is another thing which may throw your math off.

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