Exactly - Givenergy EVSE not yet integrated by Octopus.
It certainly won't break the bank if you miss the target and you don't have any heating (of water or food) going on.
I'm just sitting watching it. It's not cold enough to need heating, which is just as well as I don't want to interfere with the experiment. (If it was really perishing I could turn on the central heating - the boiler adds a bit to the house load, but not a lot.) I'm just using this post as a handy scratch pad, nobody actually needs to read it.
The battery exported 44% in the first hour of discharge - from 9.45 to 10.45 - going from 90% to 46%. That would suggest it should export another 33% before 11.30, taking it to 13%, which is higher than I was aiming for. But that gives me some useful data to figure out how much earlier to start the discharge tomorrow. I've left the battery recharge start time till midnight, so I can see how the whole thing plays out this time, including how long the final 3% reserve I think I've left in there will run the house for.
11.30 calling, and the battery just flipped down to 16%, so a full 10% higher than I was aiming for. Discharge rate seems to have slowed a bit as the process went on. I'm just letting it go on. I have the dishwasher ready to roll, but obviously that is the point of this exercise. I don't want to have to stay up until two in the morning waiting for export to finish before I can start heavy-use appliances. I'll leave it be until first the 7% set discharge limit has been reached, and then see how long the house can run for on that before it reaches for mains power. Then I can just shove the whole thing back by however many minutes after 11.30 the 7% protected limit is reached.
Oh, silly me, mistaken again. I did change the timings of the switchover so that the discharge was allowed to go on until 11.45, then the battery wouldn't start to recharge until midnight. Sure I did. But I must have forgotten to hit "submit", because the thing was still set to stop discharging at 11.30 and start charging at 11.31. That was where I had set it before I re-thought the plan after reading John's tweet. So I lost about six minutes of exporting time, and actually made this worse by having five minutes of import in there. Timings shot to hell and the dishwasher will have to wait.
Back on track now, but it won't be as simple as just shifting the time back, and the export might even straddle midnight again, which is a pain as regards visualising the graph.
11.55 calling, and that was weird. The battery hit 8%, then 7% - and went on discharging. I checked the settings, and I had told it to stop discharging at 7%, and that was enabled, but it didn't actually do it. Instead it went right on down to 5%, and flipped immediately to idle and let the mains take over running the house. So the part of the experiment to see whether I had 15-20 minutes house base load left in the battery once it stopped discharging has been a miserable failure and I have no idea why.
Nevertheless, my feeling is that I started about 15 minutes too late with the export. If tonight was representative, I should have started about 9.30 as opposed to 9.45. (Actually I do have a vague memory of thinking at one time that it was taking two hours to discharge so I don't know when that got edited to a shorter time.) So maybe start at 9.30 tomorrow and tell the bloody thing only to discharge to 10%, just to see what happens.
For the record. Discharge set to start at 9.30 (stop time has been entered as 11.59 but it should be done before then). Discharge to 10% this time. Charging set to start at midnight. Roll on tomorrow, third time lucky.
Now I should simply start the dishwasher and go to bed.
