ESPHome's Delta wallbox component can now set the charging current

Two days after the delta_wallbox component landed in ESPHome, its biggest gap is closed. In the first version, merged on 23 October, the current limit of the Delta AC MAX charger could only be read, so an ESP32 could start and stop a session but not throttle it. A follow-up from the same author, epicRE, reviewed by bdraco and merged on 25 October 2026, adds a writable maximum current. It should ship with the component in ESPHome 2026.11.

The new number entity

The current is set through a number entity:

number:
  - platform: delta_wallbox
    max_current:
      name: "Max Current"

The slider runs from 6 to 32 A in 1 A steps, and requested values are rounded to whole amperes. The charger's own maximum, set with its DIP switches, stays the upper limit: anything above it is cut down to that value. The number has no value until the ESP32 has read the charger after connecting, and the component refuses to write a new current before it knows that hardware limit. When the charger accepts a command, the component logs the acknowledged value and updates the entity.

The existing current limit sensor now reports the active limit, taken from the same register the number writes to.

Fixed readings

The pull request also corrects how charging power, session energy and session time were decoded. The author says these values were processed incorrectly in the first version. Power is now read from a wider field, and the session time takes hours, minutes and seconds into account. If you set up the component in the last two days and the power or energy figures looked wrong, that's the reason.

What it's for

Starting and stopping was enough for a simple schedule, but solar surplus charging works better when the current follows production. On a single phase at 230 V, 6 A is about 1.4 kW and 32 A about 7.4 kW, so an automation in Home Assistant can step the current down when clouds come in instead of ending the session. The same goes for load management, where the charger has to back off when an oven or heat pump starts.

ESPHome only provides the control. Deciding how many amperes the charger gets, and how often to change it, is still up to your automation. The documentation for the new option was opened on 24 October and hadn't been merged at the time of writing; the YAML above comes from the pull request itself.