Hi all. I’ve had my GivEnergy system for just over a year, and joined Octopus in April on the Flux tariff. Clearly my aim is to maximise export during the 4pm-7pm period.
However I noticed in October/November that my home consumption increased significantly during this period. My normal consumption- with the absolute minimum on - is under 100w but during Full Export in increases to over 400w minimum. This happens both on scheduled Full Export and if I initiate it manually at other times of day.
This only happens in Full Export mode.
I’ve contacted GivEnergy but they say it ‘must be’ a metering problem and tell me to get my installer to check. My installer says they keep getting told to check installations and blame software faults.
Personally I’m inclined to believe the installer. I’m not (by any means) an electrician, but I can’t see a meter problem that only materialises during battery export and not solar generation or at other times.
First off, has anyone else experienced any issues like these, or can anyone explain what might be causing it? Should I go to my supplier (Octopus), my installer or GivEnergy?
Thanks all!
What inverter and Batteries do you have - and What firmware versions ?
They are correct, this sounds like a Software / Firmware issue.
Hi. I have the 9.5kWh battery with v3012 firmware and Giv Hy3.6 inverter with D0.499-A0.499 firmware. Hope that helps.
If you’re looking on the mobile app, there’s a setting to show a calculated consumption or not
The inverter itself will be using power to invert from DC to AC to export.
I believe the faster you export, the more power it needs to do that export.
So an increase in home consumption would make sense if the app is considering the inverter as being part of the home consumption.
Thanks for that. I wondered if it could be that but that would make it only about 80% efficient on conversion which seems very poor. I’ll experiment with different export rates -I normally set it to 2.6kW which is the maximum I can. (From other posts I assume I have a V1 inverter.)
This is correct for Gen1 and possibly even Gen2 inverters. I see about 95% efficiency when charging and 84% when discharging.
Ok, looks like I’ll just have to accept it then. Maybe look at exporting less and using more in the home since I’m on the Octopus Flux tariff. That way I might get more benefit from the savings sessions too!
Thanks to those who’ve responded- shame GivEnergy couldn’t have told me about the efficiency issue when I was asking them about it.
We had a big problem with the way Octopus had set us up. They had incorrectly generated a new Export account for us such that, in effect, it behaved like a second (virtual) smart meter. With the result we were getting charged for import AND export!
You’d think such a think should be impossible but it seems like Octopus’s software is a bit … dumb ;-)
So it took us a while to latch on - in retrospect there were various giveaways, such as Octopus kept asking us for TWO meter readings, from meters with the same serial number. Hmm.
I have programmed a Raspberry Pi using the GivEnergy API to export energy from the battery to the grid when the price is high and import when the price is low. We are on a Octopus Flux tariff for our electricity.
The inverter uses some energy to convert the DC to AC for export and AC to DC for import, I would expect the DC to AC during export to require more.
I have tried to assess the percentage of energy that is exported or imported.
During import, the home uses around 0.1 kWh while importing around 1.18 kWh, this is about 90% efficient.
Export is a bit more difficult to estimate. The power is being exported to the grid from the battery, while the solar might be generating and the home is requiring some energy. As an example 2,146 Wh of export while 2,578 Wh is being provided by the battery, 15 Wh is being generated and 41 Wh is being demanded.
So the inverter is using about 400 Wh, which agrees with my experience of checking the usage during export. This corresponds to an efficiency of about 80%.
More accurate efficiency figures would require more data, which requires quite alot of time.
The inverter ia a GIV-HY3.6 with software version D0.499-A0.499, the battery is 8.19 kW.