I wonder if you could give a little more information @Buzby 

What should happen is that your daily readings are divided into usage for each half hour. They don’t appear during that day but should be visible the next day

Doh !.

I’ve just discovered that the half hourly readings are visible if I click on a column in the daily view graph. Not very intuative, especially as the meter reading history page still only shows daily.

I need the 30min readings to be accessible in my Home Assistant automation system, but that also only shows daily.

I’ve just noticed the OVO integration is written by someone called Aidan Timson ( Timmo001 ). I shall ask him.

I use an MQTT feed into HA via a Hildebrand Glow IHD. 
Although I’m not currently with OVO, I couldn’t get that integration working so if you do, please let us know as it could be useful to others

Hi @BPLightlog ,

Your HA gets usage data from the IHD, not from the OVO Cloud, and I’d much rather mine was like yours.

My Chameleon IHD has an option to connect to WiFi. I enabled this, but I can’t see any way to use it !. It replies to pings, but what do I do next ?

As I mentioned, I use a Hildebrand Glow IHD .. I couldn’t find a way to get anything from Chameleon cloud

OVO’s shorthand can a bit confusing. The concepts of meter readings and usage data are conflated, whereas they’re quite different.

Meter reading: what you see on the meter, the sum total of all electricity that has passed through it since it was installed. OVO takes a snapshot of this figure at midnight each day unless you opt for Once a month readings only.

Usage data: the amount of electricity used in a half-hour period. These figures are stored in the meter for 400 days, and OVO will retrieve them for each day unless you opt out from Every half hour.

The difference between meter readings for one day and the next should be very close to the sum of the usage figures for that day. With modern meters, these figures are all recorded to a precision of 1Wh. OVO choose to display them on the Usage pages only to the nearest 10Wh (0.01kWh), so there’s room for discrepancies there. 

You’re in good hands with BPLightlog as regards home automation, about which I’m completely clueless ‍♂️ 

One of those IHDs will cost me £70. I should be able to get data out of my IHD for free !.

My problem is how to get data from the IHD in the first place. The idea of using MQTT to interface it to HA is not a big problem, I’ve played about with MQTT in the past.