How much power does your Charge Point Home Flex deliver?

[WalterG]

Looking for the collective wisdom of this group. I just changed from the PMCC to a Charge Point Home Flex hardwired EVSE for my home charging.

The Charge Point is set for 48A so I was expecting to see something close to 11KW reported by the car. The car is reporting 10.1KW. The Charge Point app is reporting 10.75KW. Exiting the junction box next to my Charge Point I measure 231V and 45.7A.

1. Why doesn’t the Charge Point pull the full 48A? The 2.3A delta really isn’t that big a deal but it does seem a bit low.
2. What do others see reported by the Charge Point app and the Porsche app? Does a “loss” of 0.65KW make sense (ie CP reporting 10.75KW and the Porsche reporting 10.2KW)? The car was “off”, locked and climate was not on.

Thank you!

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[cyiril4j]

Yeah I have the same issue, it seems they cap the amperage to 80% of the breaker capacity e.g. 32A for 40A circuit and 40A for 50A capacity.

 

[daveo4EV]

Looking for the collective wisdom of this group. I just changed from the PMCC to a Charge Point Home Flex hardwired EVSE for my home charging.

The Charge Point is set for 48A so I was expecting to see something close to 11KW reported by the car. The car is reporting 10.1KW. The Charge Point app is reporting 10.75KW. Exiting the junction box next to my Charge Point I measure 231V and 45.7A.

1. Why doesn’t the Charge Point pull the full 48A? The 2.3A delta really isn’t that big a deal but it does seem a bit low.
2. What do others see reported by the Charge Point app and the Porsche app? Does a “loss” of 0.65KW make sense (ie CP reporting 10.75KW and the Porsche reporting 10.2KW)? The car was “off”, locked and climate was not on.

Thank you!

this is all 100% sensible and normal…

• EVSE's are considered "continous use" devices - as such electrical-code/building codes only alllow for 80% usage of circuit capacity to avoid overheating/melting wires/breakers when run at near-full capacity for hours on end with no "breaks"
• watts are formula Volts * amps - 231 volts * 48 amps = 11,088 watts or 11.08 kW - so you're measurements are "inline" with normal variations
• the 10.75 kW number you're getting is the "raw" power feed - Porsche's in-car software shows the "effective" charge rate - there are normal/expected losses due to AC/DC conversion and other normal/expected "overhead/loss" in the charging process - 10.75 kW "raw" and 10.1 kW according to the car is a little better than normal…

none of this is concerning or a problem - and all typical/expected

80% max circuit load for continuous use devices - √
10.75 kW for 231V circuit running at close to 48 amps - √
some "loss" between the "raw" power feed and the actual power the car sees - √

you're fine and this is all normal/expected/unavoidable

unless you optioned your Taycan with the 19.2 kW option - you're charging as fast as possible for a home L2/AC power 240V EVSE…

 

[daveo4EV]

Looking for the collective wisdom of this group. I just changed from the PMCC to a Charge Point Home Flex hardwired EVSE for my home charging.

The Charge Point is set for 48A so I was expecting to see something close to 11KW reported by the car. The car is reporting 10.1KW. The Charge Point app is reporting 10.75KW. Exiting the junction box next to my Charge Point I measure 231V and 45.7A.

1. Why doesn’t the Charge Point pull the full 48A? The 2.3A delta really isn’t that big a deal but it does seem a bit low.
2. What do others see reported by the Charge Point app and the Porsche app? Does a “loss” of 0.65KW make sense (ie CP reporting 10.75KW and the Porsche reporting 10.2KW)? The car was “off”, locked and climate was not on.

Thank you!

the _ONLY_ thing that is "odd" - but still unconcerning - is the 45.7 amps vs. something more like 47.6 amps (closer to the "ideal" 48)…

but the exact amount of AMPs being delivered at any moment is under the vehicle's on board charger hardware/software control _NOT_ the EVSE (ChargePoint flex in this case)

the job of the EVSE is to advertise to the vehicle what it's maximum amps are at this moment - it's a limit the car knows not to exceed - but there is no guarentee the car will always pull/request "maxAmps" - for various and complex reasons it may be perfectly normal for the car not to pull maxAmps during any given charging session…at any given moment in time over the course of the session.

with out internal logs from the EVSE and the vehicle it's difficult to assertain which end of the charing process is "choosing" 45.7 amps - it could be the EVSE or it could be the vehicle - without logs we will never know…

the most common reasons for the car to pull fewer AMPs than offers are:

• battery SOC% - closer to 100% means fewer amps - as low at 6-8 amps once you're above 95% SOC
• battery temperature - cold/hot battery - car will charge at a slow rate to regulate battery temperature - in the cast of hot it's trying to slow the charing process to bring battery temp down, in the case of too-cold it will lower amp request to avoid damage to the LiON cells until battery achieves a more ideal temperature
• normal internal variation enforced by Porsche's on board charging hardware/software - the one redeeming feature of the PMCC is that it has a recent history charging log - with graphs - when I was using the PMCC for daily charging and occassionally reviews the charging graphs - the charge rate/amps was never constant through-out any duration charging sesssion I observed variations over time +/- 5-7% up/down - it was never "flatline" constant
  • 45.7 amps vs. 47.8 amps (48 amp ideal) seems inline to me with "normal" variation that might just be Porsche software doing it's thing

all in all I lack any concern for these behaviors for your setup - the variations you're seeing are insignificant and in line with potential "expected norms" - to actually determine _WHY_ 45.7 amps requires access to internal diagnostics of both the EVSE an vehicle that we don't have access to - maybe Porsche service could pull the logs during a charging session, but it's not a warranty issue, and would eat a lot of time for a tech to diagnose this _IF_ they could with a PWISS…

honestly it's not worth it and is not abnormal

the 2 amp "short fall" is 231V * 2 = 462 watts - over a 6 hours charging session that's 2.77 kWh or ~8 miles of driving range - 2 amps / 48 amps is 4.1% variance - color me unconcerned - also unless you monitor it during the entire session we don't know that it's not "bouncing" between say 44.3-47.5 amp as just a normal variation over the course of any given charging session…

the 45.7 amp number is a curiosity - but not a concern in my opinion

231V is also completely 100% normal - 240V is the "ideal" goal of the north american residential power grid - but varation from 210-250V is common - and normally not concerning enough to local power companies for them to "fix" anything if you were to call them - below 210V or above 250V I've had luck having them come out to make adjustments - also voltage varies through out the day - it was not uncommon in my San Jose residence to see 218V on hot afternoons and 242V at 3 am when I was charging…voltage will drop from the grid power supply given the current loads of an entire neighborhood - and again this is common and expected

given an expected and common variation of 210-250V - that means a 48 amp ideal EVSE charging rate can vary from

210 * 48 = 10.008 kW
250 * 48 = 12 kW

and still be with in expected norms and no cause for concern

the 45.7 AMP number is a curiosity - but honestly I doubt there is anything there or even if there is anything that could be changed…and 2 amps is well with the tolerances of this sort of thing I doubt anyone could/would do anything about - because it's most likley not an actual problem than needs fixing.

 

[WalterG]

Yeah I have the same issue, it seems they cap the amperage to 80% of the breaker capacity e.g. 32A for 40A circuit and 40A for 50A capacity.

Thanks! My breaker is 60A and the wiring is 6 AWG so the charger is set to 80% of 60A or 48A. I had thought I'd get most of the 48A but Dave's input is that while my 45.7A is a curiosity it isn't anything to be concerned about (and not really "low" enough to matter).

 

[WalterG]

the _ONLY_ thing that is "odd" - but still unconcerning - is the 45.7 amps vs. something more like 47.6 amps (closer to the "ideal" 48)…

but the exact amount of AMPs being delivered at any moment is under the vehicle's on board charger hardware/software control _NOT_ the EVSE (ChargePoint flex in this case)

the job of the EVSE is to advertise to the vehicle what it's maximum amps are at this moment - it's a limit the car knows not to exceed - but there is no guarentee the car will always pull/request "maxAmps" - for various and complex reasons it may be perfectly normal for the car not to pull maxAmps during any given charging session…at any given moment in time over the course of the session.

with out internal logs from the EVSE and the vehicle it's difficult to assertain which end of the charing process is "choosing" 45.7 amps - it could be the EVSE or it could be the vehicle - without logs we will never know…

the most common reasons for the car to pull fewer AMPs than offers are:

• battery SOC% - closer to 100% means fewer amps - as low at 6-8 amps once you're above 95% SOC
• battery temperature - cold/hot battery - car will charge at a slow rate to regulate battery temperature - in the cast of hot it's trying to slow the charing process to bring battery temp down, in the case of too-cold it will lower amp request to avoid damage to the LiON cells until battery achieves a more ideal temperature
• normal internal variation enforced by Porsche's on board charging hardware/software - the one redeeming feature of the PMCC is that it has a recent history charging log - with graphs - when I was using the PMCC for daily charging and occassionally reviews the charging graphs - the charge rate/amps was never constant through-out any duration charging sesssion I observed variations over time +/- 5-7% up/down - it was never "flatline" constant
  • 45.7 amps vs. 47.8 amps (48 amp ideal) seems inline to me with "normal" variation that might just be Porsche software doing it's thing

all in all I lack any concern for these behaviors for your setup - the variations you're seeing are insignificant and in line with potential "expected norms" - to actually determine _WHY_ 45.7 amps requires access to internal diagnostics of both the EVSE an vehicle that we don't have access to - maybe Porsche service could pull the logs during a charging session, but it's not a warranty issue, and would eat a lot of time for a tech to diagnose this _IF_ they could with a PWISS…

honestly it's not worth it and is not abnormal

the 2 amp "short fall" is 231V * 2 = 462 watts - over a 6 hours charging session that's 2.77 kWh or ~8 miles of driving range - 2 amps / 48 amps is 4.1% variance - color me unconcerned - also unless you monitor it during the entire session we don't know that it's not "bouncing" between say 44.3-47.5 amp as just a normal variation over the course of any given charging session…

the 45.7 amp number is a curiosity - but not a concern in my opinion

231V is also completely 100% normal - 240V is the "ideal" goal of the north american residential power grid - but varation from 210-250V is common - and normally not concerning enough to local power companies for them to "fix" anything if you were to call them - below 210V or above 250V I've had luck having them come out to make adjustments - also voltage varies through out the day - it was not uncommon in my San Jose residence to see 218V on hot afternoons and 242V at 3 am when I was charging…voltage will drop from the grid power supply given the current loads of an entire neighborhood - and again this is common and expected

given an expected and common variation of 210-250V - that means a 48 amp ideal EVSE charging rate can vary from

210 * 48 = 10.008 kW
250 * 48 = 12 kW

and still be with in expected norms and no cause for concern

the 45.7 AMP number is a curiosity - but honestly I doubt there is anything there or even if there is anything that could be changed…and 2 amps is well with the tolerances of this sort of thing I doubt anyone could/would do anything about - because it's most likley not an actual problem than needs fixing.

Thanks Dave!! Super helpful perspective and background.

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