Solis AI

I've had a Solis inverter (S5-EH1P3.6K-L) since July 2024, manually scheduling battery charging/discharging depending on time of year and weather conditions. I'd seen mention of Solis AI from time to time so I thought I'd have a poke around to see what I could find out. The first thing I discovered was that the firmware I had didn't support Solis AI. I tried to upgrade but it didn't work initially. However, with the help of the Solis Service Centre I eventually got it done. Now I had access to the Energy Management System (EMS) and Solis AI. After some initial poking around I decided I wanted to try to set up "Self Use" mode. Under Tariff Setting I was faced with the choice of "Fixed Tariff", "Dynamic TOU Tariff" or "Static TOU Tariff". I decided "Static TOU Tariff" was the most appropriate as I live in Northern Ireland where neither Octopus Energy nor Nord Pool are available - I'm on what used to be called an Economy 7 tariff (reduced rate overnight, 1-8AM in winter, 2-9AM in summer). I spent days wrestling with it to no avail. Then I decided to have a poke around the "Dynamic TOU Tariff" setting to see if it gave any inspiration. There I discovered that, if you chose Octopus Energy as your supplier you have to provide a Post Code for your location. BT4 wasn't acceptable as Octopus don't operate in Northern Ireland - so prices aren't available for that location. I decided to put N17 in instead as Octopus operate in London - just to see what happens if you get further. The closest tariff plan (as far as I could tell) to my situation was called "GO-FIX-12M-25-08-29". Then I had to choose a setting for "Actual Price Calculation". There were two options, "Coeff*(Net Elec. Price+Fixed Val1)+Fixed Val2" and "Coeff*(Net Elec. Price+Fixed Val1)+Fixed Val2 (Time Sharing)". The first only allowed one set of values to be input each day. The second ("Coeff*(Net Elec. Price+Fixed Val1)+Fixed Val2 (Time Sharing)") allowed input for multiple time slots per day. That looked like what I needed to set up different Day and Night rates. Epiphany! The Net Elec. Price is what is supplied by the link to Octopus data for N17 Time Of Use (TOU) tariffs. I had to record Coeff, Fixed Val1 and Fixed Val2. What if I could make Coeff*(Net Elec. Price+Fixed Val1) = 0? I set Coeff = 0, Fixed Val1 = 0 and Fixed Val2 = 0.286 for time period 00:00 - 02:00, the same for 02:00 - 08:00 except Fixed Val2 = 0.139 and the same again for 08:00 - 24:00 with Fixed Val2 = 0.286 again. After setting my Feed-In tariff I had this.

The TOU display confirms the correct prices for the different time periods. Now to see what that did?

Immediately, I'm drawn to the strategies decided by Solis AI. I thought it would set charging from 02:00 to 08:00 but it stopped charging at 04:30 with the battery at 95% and went into battery Standby until 08:00. The reasoning given is obvious when you think about it. It thinks no more than 95% will be needed for the rest of the day so we can avoid cycling the battery that extra 5% and let the grid take care of the load directly, at cheap rates, until 08:00. I'm impressed. It hasn't had any learning time yet but already seems to have made sensible calls that would have taken me time to assess and implement. I look forward to seeing what it can do going forward. I'm particularly interested to see what it might do to avoid potential clipping coming into the summer months. I'd be grateful for any helpful observations.