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First day with no imported energy. Good solar day yesterday and battery starting to earn it space in the home. So no battery charging required overnight, the battery ran down to 54% before PV started to charge this morning. Snap shot from home assistant Energy page, showing current status A further shot from the GivEnergy page in home assistant, shows current generation (cloudy), target charge point (overnight on E7) and current battery charge status.

Where on earth has that 2 years vanished? So coming up on the 2 year installation of the inverter and single module battery, and as with most things these days, the gradual improvements to firmware over time have made a huge difference. So at the last update I'd managed to get the power leakage down through an offset, and the whole system was a lot more accurate, but nonetheless still had a small amount of leakage throughout the day which was averaging around 0.5-0.6kWh, certainly not insignificant. It turns out that not long after i bought this setup, Solis released a Version 2 of the inverter, which came with an external RS485 Meter, to connect the CT clamp to, and i believe this was done to improve accuracy, gutted i missed out on it, and theres no way of adding it without swapping the inverter, so thats a definite non-starter. I got back in touch with them to see if there was anything more they could do, and it was decided that I would move away from the firmware which supported the fixed offset (A1 branch), to the generally available firmware and ended up on version 17014, which was clearly much improved as now the leakage looks like this... At the end of september I decided to move over to Octopus Flux to take advantage of the cheaper rate during the night to charge the battery up. To compare both scenarios i have taken the same December - January Period (clearly at this time of year, solar input will be minimal), last year and then this year. Neither of these include any standing charge, this is purely for energy alone. 2022 Electricity 8th Dec. 2022 - 31st Dec. 2022 - Total amount after reimbursement from goverment £44.45 Energy Used 141.3 kWh @ 48.45p/kWh £68.47 Energy Price Guarantee 141.3 kWh @ 17.00p/kWh -£24.02 2023 Electricity 8th Dec. 2023 - 31st Dec. 2023 Energy Imported 15.15p/kWh 130.2 kWh £19.731 25.26p/kWh 17.8 kWh £4.491 35.36p/kWh 3.4 kWh £1.188 Total consumption 151.3kWh @ 16.79p/kWh (Average unit rate) £25.41 So taking into account the government reimbursement from last year, the energy pricing on standard variable tariff this year is around 4p cheaper than the same period last year. I've not included the amounts for export, as they are minimal at this time of year also. Otherwise the battery has saved me almost £20 in that single month, by being able to use cheaper electricity, and in effect shift my load. Maybe another month, or thereabouts and I should be able to stop charging from the grid again until autumn, and rely wholly on the excess Solar PV to run the property. The better months of the year for Solar should be really interesting, as at the peak i'll likely be able to totally drain the battery, and still charge it up enough after peak export period to keep me til the next morning, should be able to accrue a good amount of credit from export. I shall report back in the autumn!

So after a couple of false starts the battery is being installed. Went with the Givenergy all in one, with is rated at 13.5kWh and allows a 100% at that capacity. It also gives a whole house uninterrupted power supply in the event of a power cut and allows my PV to function in a power outage. There Is a hope he will install it all today, but think he will be back tomorrow finish off, he has just been called away - typical. First difficulty was getting in the upstairs plant room (through loft hatch) luckily I had installed a winch for the DHW cylinder, so we used that. The gateway unit, controls the power flow, batteries, mains power, consumer unit, PV, vehicle charge point all connect to this. This will be located directly above the consumer unit and meter. Needed to run a new earth spike to the unit and new cable for a stand-alone generator, these are inserted through the J tube going under the house. Battery and inverter, without access, trim panels installed. Had to move MVHR pipes, as the unit is free standing.

Hi all, We are looking for opinions and advice on the systems we have currently specified for our build. It’s a near-passivhaus build, with MBC timber frame on an insulated raft foundation. Our predicted SAP rating is 102. The Primary fuel will be electric, there is no gas in the village, and we don’t intend to install LPG or Oil. We plan on having a large solar array (just waiting to DNO approval at the moment) and Tesla Powerwall – using the Octopus Tesla Electricity tariff, so power diverters and smart energy management are off the cards. We are looking at having a Sunamp Heat battery, in place of a hot water cylinder, and heating the house will be Ground floor UFH, and potentially using the MVHR air. We would like to run the ASHP in reverse in summer to cool the ground floor slab and the MVHR – but would still need to run it forwards to charge the heat battery. The Sunamp would be the HP version, which has primary input of (High Temperature) ASHP, and a backup option of mains electricity. This suggests 2 possibly options for Hot water in summer: 1) Run the ASHP in Heating mode when necessary to charge the Sunamp – and disconnect the UFH and MVHR art this point 2) Always run the ASHP in cooling mode when actively cooling, and charge the Sunamp from electricity (surplus from the solar in summer). Sunamp specify ASHPs to work with the heat battery, one being the Valiant aroTherm which is reversible. We wonder if anyone has done this sort of configuration and can offer advice on how they achieved it / information on how it has performed. Is there a valve / manifold product available that could handle isolating the output of the ASHP from the Sunamp or the Heating elements depending on which mode is being used on each? Our main concern at the moment is that we like a cool bedroom (17 – 18 degrees) and want to make sure we can achieve this year round with the systems we install. Here is a simple diagram of the system we are trying to describe with this post.

Hi, does anyone know (for certain) whether retro-fitting battery storage (AC coupled) to an existing Solar PV Installation that benefits from the old FIT requires the installer of the battery to be MCS Certified so as not to compromise the FIT payments? ...or can anyone point me to where it is confirmed either way?