Discharging 10kWh Battery with Smart Meter

GTE

Hi all,

I have a 7kWp PV array with 10kWh of batteries. I do not yet have a smart meter.

Let's say that I get a smart meter tomorrow, and the rest of July and then August has some solid sunshine. Would it be worth my while discharging my battery into the grid overnight, so the next day's PV charges it up?

There is a 20% lower limit to the battery SOC, so 8kW per day sold (just under 2 euro a day).

My total stats since last Saturday (the day of installation) are:

• 92kWh of PV to consumption
  This is about 20 euro of energy I didn't have to buy. It has some EV charging in there too as I begin to move to day time slow charging.
  
• 97kWh of PV to the grid
  If I had a smart meter, this would be about 20 euro of energy sold with Energia.
  
• 41kWh imported
  This is mainly due to EV charging, about 6 euro on my current night rate.

I am new to the PV game, but I think I have a head for it but juggling the math is something I need to get used to.

So far, I am quite pleased.

• For the two days of rain and overcast we had earlier this week, I was delighted to see that the house was able to idle on less than 100-200 watts, with the PV still able to pull in just a tad more and trickle charge the batteries.
• The battery went from 60% at 6am to 100% by 4pm, in a day of heavy rain.
• I have also been able to switch the air source heat pump water heating from night time schedules to always on.
• I have just got Home Assistant installed, and I have my Wallbox Pulsar Max monitoring the PV and automatically adjusting the charging amps to come in just under what the PV is pulling in, thus lessening the chance of the house battery filling the EV battery (getting the Solar monitor sensor for the Wallbox installed in my set up costs too much).

I am quite chuffed.

Thanks in advance for the advice.

oaklands

In theory you could discharge it before the EV window, then charge it at the low ev rate and discharge it after that at the higher FIT rate and allow the solar to charge it again once the sun kicks in. Would need some fine tuned automation and $$$ calculations to see if it is worthwhile. Also battery cells have a certain number of cycles to be mindful of.

PS: It may take a week or 2 for the export to be enabled by ESBN.

GTE

https://www.boards.ie/discussion/comment/122369088#Comment_122369088

Thank you for the reply and for the advice on the ESBN.

Regarding your idea about discharging before the EV rate etc. The Solis app does allow for such fine tuning on their end. I will have to look at the smart rates to see, as my calculations thus far are from my current day night rate tariff.

graememk

It would be better not to even put it in the battery in the first place, the solis has a feed in priority mode, will only charge the battery once the inverter reaches it's AC output

https://www.boards.ie/discussion/2058356208/solis-feed-in-priority-to-limit-clipping