Trying to preserve battery charge before 4 - 7 pm by turning off Eco mode

General Everything Else
1

Eco mode works fine if you’ve got sufficient PV over the day to meet the load. If PV > Load, it charges the battery with the surplus PV. If PV < Load, it discharges the battery to meet the Load (in each case subject to the limits on the battery and the charge/discharge rate through the inverter).

There are times when I want to do something different, e.g. if PV < Load, take the Load which can’t be met from PV from the grid rather than the battery. Why might I want to do this? To preserve charge in the battery for the 4 - 7 pm period of premium pricing.

I can switch off Eco mode manually from the Web UI. This stops the battery discharging, so it gives me part of what I want. But it looks to me as though it also stops any surplus PV from being stored in the battery. PV is still converted to AC, so Load is still met from PV. But the surplus PV is also converted to AC and is then exported. Yuck! (I haven’t got an export MPAN yet, so I’m giving it away).

Is there any way of turning off discharge from the battery to meet Load while retaining Eco mode’s behaviour of sending surplus PV to the battery?

If the only way of maintaining the ability to send surplus PV to the battery is to remain in Eco mode, does this mean I have to set up a charge period in the run-up to 4 pm as this stops the battery from discharging?

But then I hit another Catch 22: the charge rate to the battery during a charge period applies to the aggregate charge from the grid + PV. I can’t say that I want to put surplus PV into the battery but nothing from the grid. The battery will be charged at the specified rate using whatever mix of PV and grid power applies at that second. Or the battery won’t be charged at all, if the specified Upper SOC % Limit has been reached. Whichever applies, any PV which isn’t meeting Load will be converted to AC and exported.

Is anyone able to offer any help?

2

I’ve had an idea. Can I stay in Eco mode and set Battery Discharge Power % = 0 and then put it back up to 100 at 4 pm?

If I want to schedule flipping Battery Discharge Power % between 0 and 100, should I be looking at the Octopus R&D app?

3

Take a look at Wonder Watt, it will do everything you ask and more. Free at the moment and a very friendly user group and lots of support from the developers.

4

I use Hassio home automation - which is free , so using a “Helper” within Home Automation you can get it to reduce the discharge power based on different variables.

So basically if you know what Logic you want to use then it can be done.

I personally have one that if my batteries hit 90% before 4pm then all my Aircon comes on to either cool or heat house - and also if I start to export power other things will turn on ( like towel rail ) - as I too have not yet got my export tarriff sorted so would rather just use it within my house.

5

Hello. I am reading these great articles. With new solar panels, heat pump and battery I had a short period of time when I wanted to save battery for 4 to 7 pm slot depending on the agile tariff. I also wanted surplus solar to go to the panels and the way I managed this was to do a “pause discharge” slot during the day which could also overlap a charge period.
This seemed to do what I wanted. Now with more solar and less heat pump required this is not necessary.
I have not had experience over a whole winter so I am not sure if other strategies will be required.
I think the pause discharge may only work in charge mode:- solar plus grid.

If I have overlooked anything please let me know.

1 Like
6

Correction. To my previous reply on pause discharge mode. It worked for me in either mode. Solar or solar plus grid.