Automated Discharge

JRWM47

I’ve been a WonderWatter for just 2 weeks and have become a devoted and obsessive user, which was not my intention. It works really well and the UI is a delight but my goal was and remains green, low-cost, un-obsessed automation.

Without going into tedious detail, I am running a GIV AIO on a twice-a-day discharge-recharge cycle with Octopus Agile/Fixed with a few kW of solar. I think I’ve got the WW parameters sorted for optimal charging but I would like each cycle to put the AIO through its full 4-100% range. This means having a full discharge slot just before each re-charge. The problem is that the automated start times of the two recharge slots changes each day, as does the SOC of the AIO. This information is however available to WW.

Would it be possible to automate the start and duration of a discharge slot to reach full discharge shortly before each re-charge? Maybe this is already possible but, if so, I haven’t yet discovered how.

grounded-child

Gazzagreen

Its just about timing the discharge to get as much charge from your battery to the grid. For me 3 hours gets from 100% to about 35% depending on how sunny it is. That's the full peak period on Flux.

However, if the sun is full brightness it will take longer as your inverter can only discharge so fast, and the sun takes priority. The AIO is pretty fast I hear? You still get 15p per KWH for sunlight being exported straight to the grid also, so you need to maximize that as much as possible. You definitely don't want to import from the grid during the peak time.

You will need to import from the grid when the price is right, but during summer (well normal summers) the price of import isn't much cheaper than export. It's all about the sunshine.

I would forget discharging too far, as you need to run house during the evening. Your discharge needs to be through peak time so there is less risk of importing from the grid when its expensive. You will find something that works.

Perhaps discharge through the evening to end before midnight when the cheaper slots will start to appear, if there are any cheap slots that day?

JRWM47

Thanks for your comments and suggestions.

1) GIV AIO charges and discharges @ 6kW. The actual capacity is around 14.5kWh (although rated at 13.5kWh) so, you are right, a full charge or discharge takes 5-6 half-hour slots.

2) We live in an old property with no mains gas and the size of our PV installation is limited by Listed Buildings consent. So our net electricity consumption is quite high, even in summer. The number of days per annum when our PV generation exceeds our consumption can be counted on the fingers of one hand.

3) My aim, and I imagine that of many/most other WW users, is, through time-shifting, to arbitrage (I’m an engineer not a banker!) the price differences between OCT Agile import and Fixed export to save myself a few bob and help flatten out the UK’s green energy demand.

4) So I need to store as much grid energy as possible priced below the current 15p export rate, for our own use or for re-export. Unless I’m overlooking something, this means having my AIO at or close to empty just as each of the two daily low price windows begins. At the moment, I do this manually. My WW Feature Request is, if possible, to automate this.

5) For OCT Flux, when export timing is critical, a different strategy would clearly be required.