maxPower: 0 wird ignoriert

[VolkerK62]

circuits:
- name: Inselbetrieb
  title: Inselbetrieb
  maxpower: 1400
  parent: main
  GetMaxPower:
    source: http
    uri: localhost:7070/api/state
    jq: if .battery.soc < 13 or .battery.soc > 98 then 1400 else 0 end

Originally posted by @VolkerK62 in evcc-io/evcc#32995 (reply in thread)

Mit else 0 wird nicht disabled. Nimmt man else 1 wird disabled.

Bug or feature?

[github-actions]

Confirmed as a real limitation in the code, not a config error.

Throughout core/circuit/circuit.go, maxPower == 0 is used as the sentinel for "no limit configured" (see the comment in effectiveMaxPower: "unconfigured maxPower means unlimited"), and the checks that actually enforce the cap are guarded accordingly:

• ValidatePower: if maxPower := c.effectiveMaxPower(); maxPower != 0 { ... }
• ValidateCurrent: if maxCurrent := c.GetMaxCurrent(); maxCurrent != 0 { ... }
• Update's over-power/over-current warning logic

Since a static, unconfigured maxpower: 0 and a dynamically computed GetMaxPower result of 0 are indistinguishable at these call sites, returning 0 from the jq expression is silently treated as "unlimited" instead of "block all power", which is exactly what you observed. Returning 1 works only because 1 W is close enough to zero to effectively block charging, not because it disables the circuit.

This is a genuine defect, but fixing it isn't a one-line change: it requires deciding how to represent an explicit "0 W allowed" distinctly from "not configured" (e.g. treating the getter differently from the static field, or picking a different sentinel), which touches GetMaxPower, effectiveMaxPower, ValidatePower, ValidateCurrent, and the related current-based checks. I'll leave this open for a maintainer to decide the intended semantics rather than pushing a partial fix.

🤖 Generated with Claude Code

[VolkerK62]

So maxCurrent == 0 is also used for "no limit configured"?

Seems to be a feature.
Should it perhaps be documented?

[andig]

@naltatis @premultiply we should document that max current/power 0 is not configured?