Charge Cap Hours incorrectly calculated

[Ron-ski]

Describe the bug

When on Octopus Intelligent Go, you have a total of 6 hours actual charging, 12:00 PM to 12:00 PM.

Currently Charge Cap Hours adds up the half hour slots, for example:

01:30 to 01:45
02:30 to 02:50

Is calculated as one hour, as it covers two half hour slots.

This is not the total of half slots used, but actual accumulated charging time, once you reach 6 hours, you'll be charged at peak rate (even in off peak hours for EV charging), and if outside off peak hours house usage will revert to peak rate as well.

I currently do have a sensor that adds up the time my Zappi is using above 200w, and this resets at 12:00 PM

Reproduction steps

The sensor.octopus_energy_{{DEVICE_ID}}_intelligent_charge_cap_hours is adding up the half hour slots, instead of actual charging time.

Expected behaviour

The sensor should add the actual charging time, for instance, if we had the following charging times.

01:30 to 01:45
02:30 to 02:50

The total charging time would be 15 minutes plus 20 minutes, making a total of 35 minutes

Tariff Code

Sorry I can't find this

Integration Version

19.0.0

Home Assistant Version

2026.8.1

Fresh Install?

Not specified

Home Assistant Logs

Not applicable

Confirmation

• I confirm that I cannot find my solution within the documentation
• I confirm that I cannot find my solution within the FAQ

AI Triage

• I consent to this issue, including any text or logs I provide, being processed by an AI assistant for automated triage

[github-actions]

🤖 Automated AI response - this comment was generated automatically and has not been reviewed by the maintainer. Please treat it as a suggestion, not a confirmed answer.
@BottlecapDave - a possible root cause was identified automatically:
The issue likely arises from the calculation of charge cap hours in the get_dispatch_hours_for_intelligent_day function, which currently counts half-hour slots instead of actual charging time.
Referenced source file(s): coordinators/intelligent_dispatches.py

[wrandyarmstrong-art]

I have also created a Helper to count the actual charging time. I use the time my charger is above 100 Watts power draw and when the sensor.octopus_energy_00000000_00XX_X000_XXX0_00000XXXXXX_intelligent_state changes to SMART_CONTROL_IN_PROGRESS. It would be nice to have the integrated one working, but I think i'm OK monitoring this way for now.

[BottlecapDave]

Hello. I've explained the reasoning in another thread

I couldn't find any examples of the 6 hour cap and couldnt see what would happen if your crossed the 6 hour cap during a half hour slot as they can't partially charge that slot to my knowledge. I don't want people being charged when they think it's at a cheaper rate. Therefore I went more conservative with this sensor. If I can get some official proof then I can adjust the logic accordingly.

I'll see if I can get some clarification, as it was my understanding this was introduced to reduce gaming of the system. But if it's how you say you could get lots of 10 minutes charges by disconnecting your car to get more slots charged at off peak rates. If only the dog page had an example of crossing the 6 hour threshold.

[wrandyarmstrong-art]

I think the charge cap was to stop people gaming the system, which is fair enough. I use the timer to make sure I never go over in my HA automations.
Thanks for the response.

[stevedundee2]

They definitely say they count actual charging time, not slots. Also that it's ok to plugin, unplug, plugin.

There's limited scope for gaming it. You don't get a cheap slot just by plugging in (and especially so during peak rates), and each time you plug in the car it charges at peak rate for a while until they see it and stop it. You could stop charging every time the car starts to charge outwith normal cheap rate hours, but what an effort; and I'm sure if you did it a lot they'd spot it and you'd be in breach of some T&C or other.