mk1_man

Hi, I am just about to move forward with a 28 x 450w panel solar array hooked up to either 2 x Sunsynk 5.5 kW inverters in parallel or a single Sunsynk 8.8 kW inverter. We live in an area with lots of houses and not that many with existing solar so hoping a G99 will be approved with no export limitation. If however there is a limitation how is it enforced / policed? i.e. if you were subsequently to export above and beyond on sunny days who is able to tell? I am looking for SEG payments via MCS sign off. Thanks

Personally I don't see any issue with running flexi's through the cavity wall. Some installs don't offer you the space to have them outside i.e. on out heat pump it is a straight 300mm run and then into the cavity. The picture above suggests same lack of space issue here also. I would however have thought any pipe be it flexi or rigid would certainly need to be correctly insulated when going through the cavity. We used a straight run of Primary Pro straight through. To be honest with our setup we don't even use the flexi's as I was unhappy with the bore reduction. Absolutely no noise / vibration issues either.

Are you able to say what umbrella company? The first I approached were insistent that I needed a 12kW unit when in fact I ended up installing a Vaillant 7kW and it has been great even when sub zero. What type of property do you have and what are floor areas etc. Also is it radiators or underfloor?

15 kWh batteries : https://www.fogstar.co.uk/products/seplos-v4-kit-and-x16-envision-280ah-grade-b-bundle?variant=41838224343099&country=GB&currency=GBP&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gad_source=1&gclid=EAIaIQobChMI1ZP7t7CqiwMVRZlQBh2loBGhEAQYBSABEgKh7fD_BwE 5.5 kW Sunsynk hybrid inverter : https://www.cityplumbing.co.uk/p/sunsynk-5-5kw-ecco-single-phase-hybrid-inverter-sun-5k-sg01lp1-eu/p/637259?srsltid=AfmBOorz9B8VK8zh8sbsArz0Xy0x8d7S0UygiiDxk4EZo2Pw2hEBDSdk

I think the £1500 Seplos Mason 15kWh batteries are a great deal. They hook well to the Sunsynk also. I would go this route if I were to start again. The inverter is an easy install all depends where you locate it and the batteries in relation to your consumer unit. Mine are in the garage with simple run to the consumer unit in the utility room : 2 x 15 kWh batteries ( 2 x £1500 ) 5.5kW inverter £1000 Best thing ever.

Hi, yes installed the batteries and inverter (5.5 kW Sunsynk) myself. Really quite simple to do depending on your technical background. As yet haven't informed DNO although I know I should and I will before I install any solar panels. As far as I am aware I am not breaking any laws just their rules. My inverter is set to zero export and also disconnects automatically from grid when it fails to detect a grid present i.e. when there is a power cut etc so very safe. The setup means I have run all Dec and Jan at 5p 24 x 7 instead of 24p - 26p kWh Very happy 🙂

Hi Botusbuild, sounds like you have things sorted now. I installed by Vaillant 7kW and 250l cylinder myself under an umbrella MCS company. I already had underfloor installed (previously on gas) the headline costs were £4k for Vaillant heatpump, £1k for cylinder and £1600 for MCS wrapper so as to access BUS grant. Appreciate not everyone would want to get there hands dirty but I found it really simple and enjoyable and even with all the associated bits and pieces managed to be cost neutral with £7.5k BUS. Running costs have been great at less than £2 per day for the whole house (Nov / Dec) I am on Tomato Energy now at 5p / kWh (with 30kWh batteries) - 250 m2 house similar spec to yours. The MCS Umbrella company I used was www.air2heat.co.uk

I have ground floor manifold covering 150m2 and a 1st floor manifold covering 100m2 and it works great. Primary difference is that I don't have mixer or pumps on the manifolds since installing the ashp and it is much better than when I was running on boiler with the mixers. Simpler is the way forward and also much quieter 🙂

Hi, for what its worth I have the 7kW Vaillant Arotherm plus alongside the Vaillant 250litre cylinder. Very happy with the performance, overall a scop of 4.8 since installation in Sept. I heat the water once in the early hours to 60 degrees so not exactly the most efficient way of doing things even though it is set to ECO mode. I don't mind as this is when the electric is only 5p/kWh. Heating once to this temperature is enough to last us all day and we bath (large 800 x 1800) each day and its enough. I would advise going to a 300l if you can fit it in, ours is in the loft so restricted to the 250. Bonus with Vaillants is that they are 600mm wide as opposed to majority at I think 550mm so generally shorter than others. Not sure where comments of mini coils come from, the 250l is 2.4m2 and the 300 is 2.8m2. Quantity isn't always better than quality. Not sure what you area of house is and if you have underfloor or not but our 7kWh has performed brilliantly with +5 COP being the norm on heating. We are 250m2 with underfloor on both floors however upstairs is never on apart from bathrooms. The heatpump generally ticks over at around 500 - 600 watts consumption which is amazing. One option is to install yourself or get a local plumber to install this way you can avoid the inflated costs that majority of MCS companies charge. We purchased the heatpump and cylinder ourselves and then used an MCS umbrella company to do the heat loss calcs, paperwork, 7 year warranty, BUS application etc. Our install ended up being cost neutral one we received the £7.5k grant. I then invested some of the money I would have spent if i had gone the usual route by investing in some batteries so that we can run the whole house 24 x 7 on cheap overnight electric (5p/kWh). This I feel is a better option than tying into OVO scheme where you only get the 15p against the heat pump only and not the rest of the house consumption. There is potential that they may end up controlling your heating schedule also? what ever route you take, going all electric with heat pump is best thing we ever did 🙂

I was on Cosy previously and it does work well especially if you have batteries. The three different periods allows you to spread the heat from your ashp over the day instead of trying to condense into a single cheap block. A best of both worlds is Tomato energies Lifestyle tariff, gives you 6 hours at 5p/kWh during the night but also another 4 hours during the day at 14p and the rest of the time it is still less than the cap price unlike Octopus offering where you get penalized between 16:00 - 19:00 I have used 244 kWh in last 7 day at a cost of £12.34

Yes, I have batteries (no solar) and charge them up overnight at 5p and then run the house for rest of the day from them. So far I haven't had to pay for any additional electric so looking good. My opinion is that it is better to spend on batteries than it is on solar especially when its the winter when you need the electric for the heat pump and generally no solar at that time. I calculate my payback is 3 - 4 years however I did source some great deals on my batteries. I am planning on installing solar myself in the spring but to get MCS install the figures just don't add up and there is no guarantee of long term SEG payments? Even without batteries I would seriously consider Tomato Energy Lifestyle, it gives 6 hours at 5p kWh, 4 hours at 14p and the rest at 24p so the average is still pretty good. A lot of people on the Tomato Energy forum appear to be running this way i.e. without batteries.

I am on Lifestyle with Battery storage option :

I think its more a case of their logic attempting to steer you to the best tariff for yourself i.e. if you don't select battery or EV you don't get the option of 5p overnight instead they offer their version of Cosy. Bottom line is that they don't check what you have so just choose the best option that gives you the tariff that you think works best for you.

Each battery has its own built in BMS its just that the four AOLithium batteries are not communicating with each other or the inverter. All is working well and nicely balanced.

Hi @JamesP Reason for the two different types of batteries is that I originally managed to source 2 x 5kWh ( better not get it wrong twice ! ) Sunsynk batteries al almost 1/2 price, however when I came to expand decided to go with more generic 'server rack' type batteries as you can purchase at much better prices. As long as batteries are of same fundamental design, in this case 16S (2.3 - 3.4v cells) in series with integrated BMS then you can mix and match quite happily even though manufacturers don't like you doing it. The two Sunsynks are connected to and managed by the inverter via can bus the other four batteries are wired in parallel as 'dumb' batteries. The state of charge and discharge is the same across all of the batteries and works really well. I installed inverter and batteries myself. The inverter automatically decides when to use the batteries and feed electric into consumer unit based on a simple timed schedule. Same for when it charged the batteries from the grid. I charge batteries between 00:00 & - 06:00 along with heating hot water and running the heat pump at slightly higher temperature just to boost the slab ready for morning. I don't see why batteries couldn't go in your plant room, mine are located in attached garage. Lifepo4 batteries are extremely safe however not sure I would have them inside the house?