WonderWatt battery discharge cheat sheet (unofficial)

MrMessy

Hufggfg just a safety net in case of comms failure/interrupt, so you don't unexpectedly dump the whole battery.

Have you tried a schedule and how did you get on?

Hufggfg

Gotcha, makes sense.

Yes I loaded one yesterday using my own calcs based on learning from your sheet. All seemed to work ok. I’m thinking of how to tweak to make it more effective though, particularly with the gaps etc.

Altink

Am I right in thinking. If an IOG is scheduled during an export scheduled time, the export continues but goes towards charging the car and not exporting to the grid.

Seems to be happening today for a 10.30pm to 11pm IOG schedule and the export is going towards that charge.

KristianS

In my experience, the Export will be cancelled and the Import + EV Charge will take precedent

Pedro1972uk

@MrMessy is this only aimed at GiveEnergy users or should this work across the board?

KristianS

Pedro1972uk I will let Mr Messy confirm, but I see no reason why this methodology would not work for any system

warped-carpet

With my EV plugged in last night-as Octopus now implore us to do-my WW morning export schedule (06:30-10:30) was interrupted by Octopus IOG charge events as shown in the activity log screenshots below.

My WW IOG API section predicted events between 09:00 and 11:00 which we know are often nothing like reality e.g. for me today....

My question to admin is, why didn't the export schedule resume when the IOG events ended, because my battery was nearly at full charge again by that time? I had to initiate a quick export event to continue exporting. Could, or should, I have done something differently or preferably, can WW set the export schedule to resume.

KristianS

warped-carpet Any new commands sent to your Inverter will overwrite any commands previously set by WW for Export - as above, these will take precedent over Export commands. If you want a more granular redo of your Export schedule, then you will need to define smaller time windows. Once an Export command has been overwritten by a IOG charge command, it is never ever resent just because the charge command has stopped. Only the last written commands apply.
You will need to set smaller, more frequent Export commands that will execute and therefore any IOG charge commands will interrupt and be less impactful. This is universal across all technologies as far as I am aware.

Pedro1972uk

KristianS It seems to be working quite well with the Growatt SPA3000. Just needs some tweaking.
KristianS @MrMessy @admin Can one of you please advise what the safest short pause window can be in between the discharge commands with this setup. I need to make the set up for me more granular with more discharge commands. I'm not getting down to my 10% minimum limit SoC by 23:25. Only got down to 29% of 13kW battery so missing out on nearly 20% of the discharge.
There's no reason really though why I couldn't just set the safety buffer at 10% for all the discharge slots is there?
Impressive idea though. I just need to tweak to suit my system. Thanks

warped-carpet

KristianS
That’s helpful. So, I could jiggle my export schedules as you suggest, or not keep my EV plugged in all the time because it is neither benefitting the grid or me very much atm.
However, I appreciate your explanation

KristianS

Pedro1972uk @MrMessy suggested a minimum gap of 5 minutes between schedules, I followed that rule too and had very few problems. The trouble is if you choose < 2 minutes, you are in serious danger of a delay between the commands being sent and not arriving in time due to delays in the API being processed. 5 minutes, 99.9% is more than enough to skip these delays and so I settled on that figure. There are so many variables as to when a command may be sent, from WW, processed by the API, sent to your inverter, and then executed against, that <5 minutes seems potentially fraught with challenges. But happy to be told otherwise....

KristianS

warped-carpet I would jiggle. I suspect that Octopus will keep pushing for EV's to be plugged in and to be fair to them, it is only right that they do have the ability to control during the day as well as during the 'cheap' overnight period..... Balancing the grid is a 86400 times a day job

Pedro1972uk

warped-carpet There is the option to pause IOG schedules so if you want to do this on a temporary basis the option is there.

Pedro1972uk

KristianS Just a little nervous of overlapping with the ramp up and ramp down times of the inverter and missing the next command. I suppose allowing 90seconds for each still leaves a couple of minutes buffer between the ramping up and down.

Pedro1972uk

KristianS I'm still trying to figure this one out myself by the way. I plugged my car in the other night and set the required charge time to 6am and would you believe it, IOG split my charging 22:00 - 23:30 and 4:00 - 6:00. Must have been greener energy or something.

KristianS

Pedro1972uk True.... but then you just know you would forget to turn back on again when you needed a charge for the next day 🤣

Pedro1972uk

@KristianS but you do still get the IOG command from your car or charger (If you are using a smart device) so you can still charge on the cheap rate you just don't get any interuptions with Wonderwatt which is all good if you are charging batteries but not so good if you are discharging but then there is the pause discharge whilst ev charging.

KristianS

Pedro1972uk Yes, it was the coordinating your battery not to dump into your car that I was talking about.... sorry if that was not clear.

KristianS

Pedro1972uk Yes, I do believe it. I have handed my GivEnergy system over to Octopus

They discharged, it, recharged it - during the overnight window.... so I suspect, balancing the grid and availability of resources to match supply and demand are way beyond what we could comprehend here.

KristianS

Pedro1972uk And just had this too:

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