The potential of saving up-to £2,500 in the 1st year.

24 panels and a 10kW battery was installed in July 2022. My installer went bust but fortunately all the equipment had been installed and paid for minus certification so that is what the rest of the budget will be spent on.

Apart from 400w panels the Huawei Luna 2000 10kW modular battery with SUN 2000 hybrid inverter, during the remainder of the summer we were virtually off grid. The battery was fully charged for the nighttime through to morning. It was so good I am able to charge our electric car from solar.

The Huawei system set up has 3 account types, Installer, Administrator and Owner. A residential customer will be provided with an Owner account by their installer. The Owner account does not allow any configuration of the equipment this has deferred to the installer. My installer went bust and was completely uncontactable.

Why would you want to change any settings?

Everyone knows in the UK at a latitude of 56 degrees means longer daylight in the summer than winter. In the winter there are more dark days. Many people in the UK can opt for an off-peak and peak electricity tariff. It is critical that you are able to change the settings on the battery so that it can charge up using the off-peak tariff is like mine there is such a price difference.

We are with Octopus Energy on their GO tariff which runs from October to October. We started with 5p off-peak and 15p kWh this next 12 months it is 7.5p and 39.35p kWh.

Into October we needed to get control of the Huawei system. We created an installer account and then contacted Huawei support explaining the situation with the installer. After providing proof of ownership (photographs of the equipment and serial numbers) they then attempted to contact the installer and failing to get a response emailed me that they had deleted the equipment and provided instructions on setting up against our installer account. This worked very quickly, and the only loss was the couple of months of data. We had control and could now set the battery to charge over night for the 4 hours of the tariff.

October has been bringing dark days and rain. It’s important to note that most batteries will only allow a 3kWh charge rate so a 10kW battery from 0 will take 3hr 20min. If we had gone for the extra 5kW module, then it would take 5 hours, but our off-peak tariff is only for 4 hours.

We started with Octopus energy in October 2021 and have smart meters. The Octopus web app allows you to download half hourly readings. As we had the solar installed in July, we turned to our Myenergi data which is monitoring for Zappi EV charger which got installed replacing a broken in April 2021. The July, August months could now be filled in taking all car charging as off-peak.

Crunching the data in the spreadsheet we can see that we used approx. 1/3 off peak

The headline figure are we use 9,129kWh per year 2,714 off-peak and 6415 peak.

Based on the current prices this would be:-

• £2,728 (excluding standing charge) the cost of off-peak without panels annual cost is £1,562 saving £1165.
• With panels annual cost is £166 saving £2,561.

Our outlay budget was £14000 so we can expect a payback in just over 5 years depending on inflation. The payback for battery only is the same on an outlay of £8000 for 10kW battery.

Batteries chemistry is typically Lithium-Ion sulphate which has a 10,000-charge cycle life. If this is once per day, then that equates to 26 years.

I do not know what the weather or energy prices will be but the current direction of travel makes Solar and Batteries a no brainer. We have not had to borrow and costs have increased but you can access this spreadsheet.

calculation spreadsheet