Target Charging behavior does not respect 1p 3p settings

[michaelheiml]

Describe the bug

Hi,

Problem: when target charging is set, the start time is always calculated based on the 1p ampere setting, even if 3p instead of 1p charging is selected. This leads to the unwanted behavior, that charging starts, runs for a while (battery heats up etc.), then suddenly stops and continues at a much later point (again heating up battery etc.) to finish at the right time.

Example (see screenshots): in the evening, I set target charging to next day morning 8am. It is required to charge ~20 to 25 kWh.
With 1p behavior is: charging starts at 2am, charges until 8am @5kw (average) = 6h * 5kW = 30kWh (this is OK, but with a lot of waste/loss of energy due to slow and long charging)
With 3p behavior is: charging starts at 2:30am, charges ~1h @10kW (average) = ~10kWh, then stops, then starts again at 6am and charges until 7am = ~1h @ 10kW = ~10kWh => all in all ~20kWh but broken up in 2 charging sessions, each one heating up and cooling down the battery (not good).

What should happen IMHO is that with 3p, charging starts at around 5am until 7am average @12kW = 2h * 12kW = 24kWh in one piece.

I have: evcc + go-E + Zoe 41kW 2017.

See attached screenshots and notice that even though 3p is selected in the settings menu, evcc calculates the start time as if 1p is selected:
evcc charge sessions: green columns are the 2 charging sessions from 2:30-3:30 and 6:00-7:00 (approximately)
evcc charging: see that evcc actually charges with 3p @ 9,5 kW (battery is almost full therefore not full 17kW)
evcc plan: is set as described, notice that "charging time" calculates with "@5,8KW" although in the (next) setting screen, 3p is selected
evcc settings: notice that 3p (4,8-17,3kW) is selected

Steps to reproduce

1. set target charging to 8am morning with a quite empty battery
2. manually set to 3p charging (make sure 3p can charge with much more Ampere than 1p)
3. notice that target charging starts much too early because it calculates start time as if 1p was selected

Configuration details

# open evcc at http://evcc.local:7070
network:
  schema: http
  host: evcc.local # .local suffix announces the hostname on MDNS
  port: 7070

log: debug
levels:
  cache: error

# unique installation id
plant: xxx

interval: 30s # control cycle interval

sponsortoken: xxx

# sponsors can set telemetry: true to enable anonymous data aggregation
# see https://github.com/evcc-io/evcc/discussions/4554
telemetry: true

meters:
- type: template
  template: fronius-gen24 
  usage: grid  
  host: 192.168.1.110  
  port: 502  
  name: grid1
- type: template
  template: fronius-gen24 
  usage: pv  
  host: 192.168.1.110  
  port: 502  
  name: pv2
- type: template
  template: fronius-gen24 
  usage: battery  
  host: 192.168.1.110  
  port: 502  
  name: battery3

chargers:
- type: template
  template: go-e 
  host: 192.168.1.10  
  name: wallbox4

vehicles:
- type: template
  template: renault 
  title: Anja  
  user: xxx
  password: xxx
  vin: xxx  
  capacity: 41  
  name: ev3
  mincurrent: 7
  maxcurrent: 25
  phases: 1
- type: template
  template: renault 
  title: Michael  
  user: xxx
  password: xxx
  vin: xxx  
  capacity: 41  
  name: ev4
  mincurrent: 7
  maxcurrent: 25
  phases: 1

loadpoints:
- title: Garage
  charger: wallbox4
  mode: pv

site:
  title: Hattenberg
  meters:
    grid: grid1
    pv:
    - pv2
    battery:
    - battery3

tariffs:
  currency: EUR # (default EUR)
  grid:
    # static grid price
    type: fixed
    price: 0.2868 # [currency]/kWh

  feedin:
    # rate for feeding excess (pv) energy to the grid
    type: fixed
    price: 0.12464 # [currency]/kWh

Log details

Does not apply

What type of operating system or environment does evcc run on?

Linux

Nightly build

• I have verified that the issue is reproducible with the latest nightly build

Version

0.133.0

[mfuchs1984]

phases: 1 -> you are telling evcc that your vehicles are only capable of one-phase charging, regardless how many the charger offers.

[michaelheiml]

If I remember right, I set phases:1 to prevent automatic phase switching due to the PV. The PV delivers 5-8kW on average, so a lot of switching between 1p and 3p occurs. It is better to only charge with 1p (there have been quite some discussions here in the past about this).

So do I understand this right: If I remove phases:1, I have the constant phase switching issue. If I leave phases:1, target charging does not calc time correct. How do I handle this?

[mfuchs1984]

I think, you could change the loadpoints enable properties to reduce the number of phase switches
https://docs.evcc.io/docs/reference/configuration/loadpoints#enable

[michaelheiml]

Thanks for the link but sorry, I do not understand.
So I should remove phases:1 and then add:
enable:
threshold: 0
delay: 1m

but with which value to achieve this:
PV charge only with 1p, if there is more than 5,6kW available export the rest to the grid (cap charging at 5,6kW + do not switch to 3p charging).

[mfuchs1984]

The larger the enable delay, the longer evcc waits before switching to 3 phases when the power changes. This will avoid switching back an forth when power is around the threshold for 3 phases. Same for disable but for switching back to 1 phase.

If you e.g. set the enable delay to 5 minutes, power must be and stay above 5,6 kW, which is your maximum 1 phase power, for 5 minutes.

[michaelheiml]

There are several reasons for this:

1. due to my setup (Zoe + 11kWp) a lot of switching would occur, because on average production is around 5-7 kW (just in the area where switching would happen)
2. I'd rather use the extra surplus above 5,6kW (max 1p) for charging the house battery, heating up water or using it for the house itself
3. when on 3p+not enough surplus for a longer period (e.g. because switching down is delayed due to "delay"), the house battery would be drained to compensate for the missing surplus, then charged up as soon as switched back to 1p and I don't want that battery charge/discharge hopping either..
4. Zoe needs to pause charging for 30s to allow switching from 1p to 3p (to not damage car charger).. this is also a negative effect why I don't want switching to occur.

All in all I experimented around with 1p/3p auto switching for quite some time and just came to the conclusion that its just better working when staying on 1p and not try to use the last bit of surplus for 3p charging..

[mfuchs1984]

All valid, but is it a real problem when it switches phases for a very limited number of times? This is what you could achieve with the delays.

If you still want it, I think you can use the API endpoint api/loadpoints/<id>/phases/<phases> to allow 3 phases when charging fast but only 1 when charging in PV mode.

[michaelheiml]

I will give 1p/3p auto switching with a 10min delay another try.

Could you please explain what you mean with your second line, I do not understand, how do I do that (3p => only when fast, 1p = only when PV mode) ?

[mfuchs1984]

This is about using the evcc API through an external tool like home assistant, iobroker or something else.

Available is a REST API
https://docs.evcc.io/docs/integrations/rest-api
and mqtt
https://docs.evcc.io/docs/integrations/mqtt-api

For home assistant, there is even a ready to use integration
https://docs.evcc.io/docs/integrations/home-assistant

[michaelheiml]

Ok API/iobroker etc. is not an option for me as I do not want to add another extra external dependency that needs attention and might cause instability (I have iobroker running for the rest of the smart home, I prefer an independent car charging solution).

So if I do not oversee an option, the situation is stuck; I either use auto switching which I don't want or target charging starts at the wrong time.

Unless at some point in the future, the target charging start point calculation is changed to what the user has actually set in the UI (as suggested below), or it will be added to the config to define different phases for the different charging modes (pv => 1p only; fast => 3p only)..

[andig]

Unfortunately your report is missing a detailed log file. Without log, we don‘t have the information for diagnosing the issue described. See https://docs.evcc.io/docs/faq#wie-kann-ich-ein-logfile-zur-fehleranalyse-erstellen.

[michaelheiml]

I do not agree that this is just a discussion instead of an issue as the suggestion from mfuchs1984 is a workaround (to basically use auto-switching and along with that suppress switching to 3p by setting the time until switching occurs very high).

Also I do not think that a log file can contribute more info to the behavior as it is clearly understandable, diagnoseable and reproduceable with the settings described above on screenshots and settings file.

Based on info on this thread so far, the underlying issue is a discrepancy between what can be set/is shown in the UI (3p charging + target charge) to the contradicting setting of "limiting" charging to 1p via the setting file, which leads to a wrong calucation of the start time / approximate charge duration. All in all that leads to a user experience where something other happens than what is expected to happen based on what the UI tells/allows the user.

IMHO a fix would be that target charging time calculation should not be based on the "phases:1" setting in the yaml file but what is actually set via the UI in case manual phase switching is desired.