Best practice for Battery + Solar on off peak tariff?

Hi,

I have been running an AIO + Gateway with no solar for about a year and have just added solar to the equation and would like to optimize my setup to be as efficient as possible. I have an EV and an on Octopus Intelligent Go with cheap electricity from 23:30 - 05:30.

Historically my battery has been set to charge overnight between 23:30 - 05:30 and run the house all day. Now with the added solar the battery get topped back up in the day and sits at 100% until the solar generation dwindles in the late afternoon.

I have noticed that the battery reaches 100% charge in the middle of the night, say 01:00, but then holds the charge until 05:30 and then begins to power the house, meaning the house is pulling in from the grid between 01:00 until 05:30. I think I may have misunderstood the correct setup here. Ideally the battery should discharge to almost 0% before charging but ensuring it reaches a charge of say 50% by 05:30 knowing that the solar till top it back up in the day.

I hope this makes sense? I am keen to hear how others with a similar setup are configuring it.

Thanks

[unknown] I fully charge my AIO overnight (7 hours) - the battery usually fills up after a few hours at this time of year and then effectively pauses so the house is running off the cheap power until 7am. At that point the battery (and solar will satisfy the house load) - usually during the summer I am exporting nearly all the solar back to the grid during the day.
So in effect I run the house entirely off cheap power and sell a lot of energy back to the grid during the day. The credits for the exported power more than cover the import (6.7p/kWh in & 16.5p/kWh out) and builds up a credit for the winter months

Ben Robins I fully charge my AIO overnight (7 hours) - the battery usually fills up after a few hours at this time of year and then effectively pauses so the house is running off the cheap power until 7am. At that point the battery (and solar will satisfy the house load) - usually during the summer I am exporting nearly all the solar back to the grid during the day.
So in effect I run the house entirely off cheap power and sell a lot of energy back to the grid during the day. The credits for the exported power more than cover the import (6.7p/kWh in & 16.5p/kWh out) and builds up a credit for the winter months

Ben Robins I fully charge my AIO overnight (7 hours) - the battery usually fills up after a few hours at this time of year and then effectively pauses so the house is running off the cheap power until 7am. At that point the battery (and solar will satisfy the house load) - usually during the summer I am exporting nearly all the solar back to the grid during the day.
So in effect I run the house entirely off cheap power and sell a lot of energy back to the grid during the day. The credits for the exported power more than cover the import (6.7p/kWh in & 16.5p/kWh out) and builds up a credit for the winter months

Ben Robins I am keen to hear how others with a similar setup are configuring it.

Assuming you've got your export tariff set up, you should be getting 15p per exported kWh. So using a notional cost of 15p on using (your own) solar guides your decision making. eg you do want to run off the grid overnight rather than using the battery, since the power in the battery is better preserved for export during the day - no point consuming energy worth 15p/kWh when you can import it for 7p.

To a first approximation, I fully charge overnight, then run with the pause timer configured to pause-charge during the day. This way, all excess solar is sent to the grid, rather than charging up the battery. Then at the end of the day, I dump battery back to the grid, ready for the next overnight cheap period. (I'm also on IOG.)

But because I have a hybrid inverter, and my panels could generate more than the 5kW that the inverter can export, I do have to arrange things to ensure there is space in the battery to accept some charge when solar is particularly high. But I'm guessing you don't have that problem since your solar is effectively AC coupled (?)

Ben Robins the setup and operation is about as optimal as you can get. As the summer closes your solar generation will drop off (substantially) and increasingly you will be running off your charged AIO during the day. This is all automatic. Any solar will recharge the battery or run the house but you’ll only get about 10% of your summer generation in the winter, and on some days, nothing at all.

One thing you could do differently is to reduce your AIO charge rate so it trickle charges the battery slowly overnight on OIG rather than it being fast charged and sitting idle from 01:00 to 05:30. Try to shift as much house load to the cheaper period as well such as your washing machine, tumble, dishwasher, and depending on your hot water heating it can be cheaper to heat the tank by immersion.

I have 2 x AIO and I am on the Octopus Go tariff and Octopus Export Tariff @15p. I run automatically on Wonder Watt Schedules . I export all the way down to 4% every evening to coincide with the start of the cheap rate period. I then import for a hour @12kWh and then Export it straight back out again. I then spend the rest of the cheap rate period charging the batteries to 100%, heating the hot water tank and running the dishwasher, by the 05:30 end of cheap period. I then pause charge the batteries and export solar generation all day long. This yields me a consistent 35 to 55kWH export per day with no effort whatsoever.

You can use the Wonder Watt cheat sheet scheduler here https://community.wonderwatt.com/d/934-wonderwatt-battery-discharge-cheat-sheet-unofficial depending on the size of the battery and DNO rates.