Timed Battery Charging from Grid OVO

Hi, Probably nothing can be done but OVO as part of their new SmartBoost charging package send charging times and percentage levels to the Givenergy inverter. Often this is say charge to 83% between 4pm and 6pm or midnight to 3am charge to 100%. The price per unit is cheaper when it's charging the battery on these timed periods. However if the battery is 95% charged or 100% etc and its been told to charge for 3 hours then the battery will sit idle for the entire duration if its 100% or reached its allowed charge limit early thus my house is using the grid/mains for power usage at standard unit prices rather than the battery. So for example if the battery is 99% and OVO have told it to mains charge at midnight, it takes say 10 minutes to get to 100% then the battery will sit idle for 2 hours 50 minutes. I understand that the battery cant be charged and discharged at the same time but wondered if there was some intelligence where it will decide to ignore the mains charge if it's 100% and start discharging the battery.
Probably as clear as mud but any ideas? 🙂 Thanks Matt

matty99 wondered if there was some intelligence where it will decide to ignore the mains charge if it's 100% and start discharging the battery.

The trouble is... suppose it were to start discharging the battery: it then drops to 99%, and it now has a conflict - does it go back to honour the explicit request to charge to 100%, or does it continue to do its own thing?

Typically need some sort of hysteresis, but now you're adding more and more complexity. (I had my own control system in the summer, when I was typically exporting solar directly, with solar charging disabled. It had a notion of a preferred SOC - if it dropped 5% below, it would allow solar charging, though not actively charge; when if it went 5% above, it would force discharge; otherwise the battery was typically idling. Except to avoid clipping...)

matty99 I don’t think there is anything that can be done unless you manually cancel the charge period on the inverter earlier.

The way the inverter interprets the command is “charge to specified SoC% and hold it at that level until the end of the charge period”.

The only way round the limitations of this logic is to start the charge as late as possible, taking account of the current SoC% so that the battery doesn’t idle unnecessarily at the end.
But this is more logic than OVO are probably delivering.

I would go back to Ovo and explain the limitations of what they are doing. This smart boost is quite a new product

DD Hi, Thanks for the reply. Yup your right that had also crossed my mind if it dropped a percentage then it will go back to charging again and so on 🙂

geoffreycoan Hi, yes it is fairly new. I guess its not the end of the world but when it supposed to save you money your then using normal unit prices to power the house whilst its on a charge or not as the case may be when its hit the upper charge limit early. 🙂

I've got the same problem. Was going to go back to Ovo about it. What I'm also not clear on is if Ovo have, for example, set it to charge to 100% between 3am and 5am and it reaches 100% at 4am do they actually know that the electricity being sent from the grid between 4 and 5am is being used by the house and not to charge the battery? If they do know then they should be able to override the setting to charge the battery and if they don't know then presumably although the electricity is being used by the house it would be billed at the lower kwh rate?

Related to all this, has anyone worked out how to adjust the custom reports to reflect the difference in rate? i.e. when its calculating the amount spent on import the report uses the standard tariff but this is giving an inflated estimate / knocking all the cost calculations since if the import is being used to charge the battery its being charged at the lower tariff?

Duke of Roker I suspect Ovo have made it fairly simple, they issue a charge instruction to your inverter to charge the battery to 100% between 3 and 5am and anything you consume in that time period is at the lower rate

Anything else is getting quite a lot more complex requiring Ovo to poll your inverter to see if the battery is full and then stop the charge, or to work out how much is being charged into the battery vs being consumed by the home.

And yes, the givenergy reports are quite simplistic. You might be able to achieve what you want with a custom tariff but I doubt that you can specify different rates for different days. Probably would need to pull the data into a spreadsheet and do your own reporting or use something like home assistant