Growatt - Octopus Flux New User

JohnD

Hi, I am looking for some advice from those who have already achieved success. I have a Growatt Hybrid inverter and two 5kw batteries(Total 10Kw) and 12 Solar Panels on the roof, SE facing, after a few bright days I asked my installer to turn off the overnight charging, which he did. There followed a few days of very little sun, and subsequently running out of battery and drawing from the grid. Looking for a more flexible charging approach to 'all or nothing' via the installer I have found this site, it looks like it can do all I need, intelligent 'top up' overnight charge and the possibility of a bit of force charging during the 4-7pm high cost slot with Octopus.
Would someone be kind enough to share their schedules that work for them so that I'm not playing in the dark?
Thanks in advance.
john

jimmiller23

Hi John. I am relatively new to this too and have a similar set up to you. To start with I created a night charge schedule that runs between 2am and 5am (Octopus cheap periods) and then selected the "smart charging" option (with a minimum charge of 25% SOC) and left the rest to WonderWatt. I believe this takes into account starting SOC, your usage and the weather to charge an appropriate amount overnight.

I also have a normal evening schedule that discharges in the evening to c. 40% SOC and then a "Holiday" schedule for when I am not at home which discharges to 15%. I hope that's helpful and I'm interested to hear what you opt for.

JohnD

jimmiller23 Hi Jim, Many thanks for your reply and settings, When Smart Charging Min Charge of 25%, is this the 'Minimum Charging Rate' or the target SOC? To me the options are not logical.
Thanks
John

jimmiller23

Obviously you would need to toggle to active for it to work.

JohnD

jimmiller23
Hi Jim, I set my system as your settings last night. My battery had dropped to under 50% by 02:00, the schedule started and the battry was charged at a rate of 500w/hr for two hours raising the SOC to 60% when it stopped charging at 03:00 but continued to feed the load until 05:00 when it reverted to battery power.
So it seems to me that WW had calculated that due to the various factors including predicted sun for today all I needed was a 'top up' to 60% to see me through the day.
Is this the typical behaviour I should expect?
Perhaps @admin can contribute here as well.

thanks
John

JohnD

Hi Jim, yes that's how I've set it up, Sorry I'm being thick, but what do you expect the 'Charge at least 25%' to do?
John

admin

JohnD Charge at least 25% means that if the calculate Smart SOC target is lower than the 'Charge at least value), say 20% (based on solar forecast etc), it will override that and use 25% SOC target instead.

Think of it as a minimum charge %. Perhaps we need to rename this.

JohnD

Hi Admin, So if I understand it this is a target State of Charge, i.e. the final level of charge of the batery at the end of the charge period will be 25%
Is that correct?

admin

JohnD Yes, but in Smart mode, WW will determine your target SOC for you based on PV solar yield prediction, battery capacity, your home usage you configured etc.

The 25% will only be the SOC if the Smart WW prediction SOC is less than 25%.

Alternatively, you can switch your charge schedule to Fixed SOC target instead.

JohnD

Hi, ok I think I've got it now. However in the beginning how does WW know the usage patterns? is it querying historical data from Growatt?
John

admin

JohnD Nope, not querying usage. Just looking at what you put in your average daily consumption in Settings.

JohnD

admin Oh OK thanks

John

admin

JohnD Yep - that's correct, what did your Activity log entry say?

JohnD

admin OK, you're testing me now, where do i find the Activity Log, I can only see a Fault Log on the home screen of Growatt
John

admin

JohnD Oh, sorry, no on WW - the Activity log 😜

JohnD

admin OK

2024-04-05 01:56:27 57 % 5.6 kWh
Charge instruction set for 02:00 - 05:00: 61% target at charge rate of 10%

admin

JohnD Right yeah, so between your consumption setting and battery level, solar forecast etc. WW decided charging up to 61% is sufficient.

JohnD

So that's what it did

JohnD

JohnD Although with the weather we've got in Scotland today I'll be impressed if we get 5.6 Kw of Solar

JohnD

admin

Anyway I'm going to leave it set like this for the next few days and see how it goes, tomorrow we've a storm coming through but the afternoon looks brighter.
Thanks
John

admin

JohnD Yeah, it's not an exact science, it's a prediction based on weather forecast.

If you find the target SOC is consistently too low, you can tweak the 'Battery target' correction factor in the Advanced section.