JohnMo

Buying Panels - City Plumbing are in most areas and super cheap for panels. You have a van so could you collect? But most electrical wholesaler sell panels now. So are the additional panels just going to be free standing when parked up? Need the full story really

Why are you faffing about with a 300W string? Just bin it and buy new panels - 500W panel is only £67. Your issue adding to the other panels, is the big panels may only output the same as the old string unless on a separate mttp. Plus to keep everything happy you will likely need to add optimisers, which cost the same as the new panels.

Do you really need a nail gun for a 2m² shed. I used a a DeWalt air driven nail gun (needs a compressor) built house, external cladding, decking and couple of sheds. Uses standard nail gun nail.

Two coats gives you airtight out the box. Dot and dab, same if you apply the adhesive correctly and form a full perimeter of adhesive. Otherwise you get air leaky walls

I was born there

I was considering just for the learning - not a career change

Do the course be one yourself

So did I, that was 20+ years ago. Interesting the facts then, are the facts now. But people still don't want to or will not get it. Politics doesn't want to know, if one side or the other gets them votes or money in the election fund box, that's the side they ultimately fall towards. Doesn't really matter what correct so long as they have some power.

Why, I am pretty much 100m from house to garage have cable installed in there big enough to run most things. Small digger - trench - drop in armoured cable, back fill. 1 days work. Or even easier surface run armoured cable or clip to fence or wall. £1k buys a lot of cable you only need 16mm² to do 100m at 10kW. I just put in 25mm² so can do most things with little or no volt drop.

That is generally a fact, and one of the reasons you get a bunch of tax payers money thrown at you. It's just a pity the installer thinks that money is mostly for them. So homeowners still get a huge bill. Most ASHP are for the rich with disposable income, or people that aren't scared to shop around and do it yourself. A move from fossil fuels to ASHP, could be achieved in a step by step process. Run boiler at heat pump temperatures, figure out which room needs bigger rads, most will or may not need changing when running low and slow. Change out in slow process, much the same as @marshian. Cylinder fitting one with a big coil makes reheats well quick, from fossil fuels boiler so a no brainer really. Let boiler get to end of useful life seamlessly change heat source. Who needs a grant?

I didn't spend 10's of thousands all together. ASHP, PV, and battery all in, was about £10k. DIY and careful shopping is the way to go. First 3kW array was part of the new build, so there anyway. Boilers don't do cooling, ASHP are a two trick pony, they do heat and cooling. Boiler had to go it couldn't pay it way. PV and battery were always going to happen, they just feed into an ASHP very well. Battery can be justified by the number of power cuts we get and that our water is pumped from a borehole. Everything ties in nicely. We no longer get blackouts, bills have come down 50% in real terms.

That will take some working out, but I invested for different reasons to most. ASHP because I wanted/needed cooling, so that capital cost wasn't for actual savings, but as result of that purchase they occured anyway. Set heat pump to run on its own for heat and cool and then added the nearly boiler apart if the new build) as a hybrid, but gas was a drain in money terms because of the standing charges. Cost as much for standing charges as the gas did. Most the year ASHP did heating and cooling, only cold days gas ran. PV to bring down monthly outgoings and help to a A EPC. Added battery to allow me make better use of cheap electric tariffs. Again to bring down monthly outgoings.

I think you should stop that, it will never go well. The ? isn't really that high, if I recall correctly, about 30mm - 40mm

No its all costed, ASHP as retro fit. Heat Pump including cylinder and aux stuff was about £3k (careful shopper). Spend about the same on PV (some new others second hand, but basically new). Battery was quite a bit more expensive, but has a pay back of about 5 years excluding export (which I now have, so should be way shorter). I never expect to pay more than 13p (excluding inflation) per kWh even when -9 outsade and ASHP has to earn its keep, so half normal price, with PV contribution.

I started with a Hyundai 7.9kW generator, big enough to cook my tea, have lights, heating and TV on. £800

You could expand the question and ask if they had a gas or electric boiler and still get the same blank expression. Most people just don't care, it's not even on a radar, let alone something to think about. If it's warm enough job done. If it isn't call the plumber, he'll fix it. Until I built my house heating was something that just happened, I didn't care, gas was cheap, I was earning, so the heating got left on 365 days a year, in chilly Scotland.

Sorry to much of a sweeping statement, for some properties it maybe, but with solar and battery heat pump wins all the time, my current average cost of electricity is 3p per kWh, average over the year about 10p maybe less, without including export credits. Get a scop of 3 that's 3.3p per kWh, get a SCoP of 4 that's down to 2.5p per kWh.

Been back on ChatGPT, and explored the shite in shite out aspects of AI, asking some basic questions, after a couple of further questions it has spat out a different answer. Its now saying.Quite like chatting with AI, but you do go rubbish rabbit holes. 04:00–07:00: charge to 95% SoC (≈ 12.7 kWh) Covers the 07:00→13:00 gap on your coldest days without touching 25.79p. 13:00–16:00: charge to 95% SoC (≈ 12.7 kWh) Covers the 16:00→22:00 gap (including the 39p peak 16–19). 22:00–00:00: charge to 56% SoC (≈ 7.5 kWh) Bridges 00:00→04:00 comfortably. The above basically covers my worse day without solar. So my take on that is after @sharpener valid question, what's the point of charging to 95% you may as well just charge to 100% each slot and forget about it. Have now set the charge automation in GivEnergy Control to work with the Octopus API and automate the charging. Will charge to 100% and then export as its generated. See how that goes.

Think it's saying don't bother paying to import then getting hit by DC to AC inefficiencies to get export and effectively get the same real value exporting as importing. The cost difference is so small, just import the minimum you can. If after that if you have real excess, let that export. On poor solar day and we get plenty, the battery may only partly charge. Today battery has just hit 92% (16:45). Will maybe get a few extra percent or get to 100% and export a little. So far today the battery topped up to 50% early morning, and house took grid supply in during charge period - used 3.2kWh. Have consumed around 10kWh. Generated around 8.5kWh. Have exported 0.01kWh just via stuff slipping by. Just under one full charge today. So the question is how much electricity would I have added to battery to keep at 100%, would the system have drawn in grid during the charge periods? Assume it would still be one charge and PV driving house and exporting? I also like the idea of buying as little energy as I can. But trying different things to see what works. Certainly just charging to 100% is a fit and forget option.

When I first signed up they had all those details on the website, believe they are based in Wales Asked AI UK-based Wonder Watt (the smart charging app) The company appears to operate as a small startup based in South Wales, founded by an experienced software developer (Wim) and a solar systems engineer (James) deegesolar.co.uk . There's no publicly available corporate or company registration details (e.g., Companies House number or legal address) associated with the UK version of Wonder Watt. On Trustpilot, they list a UK contact email: labs@wonderwatt.com , and confirm being a “Software Company” based in the United Kingdom Trustpilot Trustpilot . Conclusion: It’s likely a UK-based private entity, but it does not publicly disclose a registered company address or name on its website or Trustpilot profile.

But if a long read, have shortened where I can. Been having a chat with ChatGTP this is what it said: My question. Battery charging and export Costs 12.8p per kWh during cheap rate tariff on Cosy 3x periods per day Get 15p for all export, what is the best strategy for charging and export? I can use WonderWatt for predictive charge based on solar forecast if that helps. House runs a heat pump heating demand at -9 outside is 3.8kW. house base load is 14kW, but cooling can be on when it's sunny or warmer than an average of 15 degs outside ChatGPT said: To optimize energy usage, I’ll suggest charging the battery during cheap periods (12.8p) and exporting during higher-rate times (15p), factoring in round-trip efficiency (90-94%) and battery degradation. Using the 13.4 kWh battery and assuming a baseload of 14 kWh, I'll focus on scheduling to avoid low-price exports. To compute the breakeven for export arbitrage, we look at the cost of exporting after accounting for round-trip efficiency. At 90% efficiency, the marginal profit is quite small (0.78p), and with battery degradation costs, it becomes negative. So, arbitrage isn’t worth it. Best to use the battery for home load and heating. We can optimize the battery by charging it to cover expected non-cheap consumption until the next cheap period, using solar forecasts for predictions. In summer, charge for evening use, while in winter, focus on covering evening peaks. For cooling, pre-cool during cheap periods. The scheduling strategy will help manage this. Done Short answer: don’t “charge-to-export.” Use the battery to cover your own load and heat/cool at the cheapest/easiest times, and only export true surplus. Here’s the why + a concrete playbook for Cosy + 15p export: 1) Arbitrage check (import cheap → export at 15p) Cheap import: 12.8p/kWh Typical round-trip efficiency (η): ~0.9–0.95 Effective cost to create 1 kWh for export = 12.8p / η = 13.5–14.2p Gross margin vs 15p export = 0.8–1.5p/kWh, before battery wear. → Once you include degradation (a few p/kWh), arbitrage is a net loser. So do not cycle the battery purely to export. 2) Self-consume vs export (for solar) Rule of thumb: store PV if your import price you’d avoid later (p_import) is greater than 15p / η. With η≈0.9 → threshold ≈ 16.7p. Most daytime/evening import is above that, so storing PV beats exporting 9 days out of 10. 3) Daily operating strategy Charge in all Cosy cheap windows to a target SoC that covers expected demand until the next cheap window minus expected PV during that span. Target SoC after a cheap slot: SoC_target = (Forecasted load until next cheap slot – Forecasted PV usable) / η Disable/avoid ‘export from battery’. Only export when the battery is full and PV is still pushing (true surplus). Pre-run thermal loads when it’s cheap/sunny: Heating (cold spells): Pre-heat slab during cheap windows; let the slab bridge the expensive hours. Your 100 mm slab helps buffer nicely. Cooling (sunny/≥15 °C avg): Pre-cool during cheap windows and daytime solar so the evening load is minimal. WonderWatt: Use its predictive charge to set SoC targets per slot: Feed it your PV forecast, house baseload and scheduled HP use (pre-heat/cool blocks). Tell it not to backfill charges outside Cosy windows. Export priority: Summer: Battery fills on PV → serve house + cooling first → export only when full. Shoulder/winter: Fill in cheap windows; reserve battery to cover evening/overnight peaks; export only if you genuinely can’t use/store it. The conversation went back and forth getting the assumptions correct etc End recommendations are let’s nail this down so you’ve only got two things to manage in WonderWatt: Baseload (summer vs winter entry in kWh/day) A single set of min-SoC targets that work year-round. 1. Baseload values for WonderWatt Summer (little or no heating): Your true house demand is ≈14 kWh/day (≈0.58 kW average). → Enter 14 kWh/day as the baseload in WonderWatt. Winter (continuous ASHP heating): At the coldest, your house may need ≈32 kWh/day for ASHP. Add the 14 kWh/day base → ≈46 kWh/day total. → Enter 46 kWh/day as the baseload in WonderWatt. This way, in winter, WonderWatt is “fooled” into charging more aggressively during cheap windows, without you having to micromanage presets. In summer, it leaves headroom for solar. 2. Universal min-SoC targets (work for both summer & winter) Since WonderWatt will top up if solar looks poor (and supply loads from grid while charging), you just need guardrails so you don’t run flat. Based on your battery size 13.4 kWh usable: End of 04:00–07:00 slot: 40% SoC → ~5.4 kWh End of 13:00–16:00 slot: 40% SoC → ~5.4 kWh End of 22:00–00:00 slot: 30% SoC → ~4.0 kWh These are conservative enough to prevent a blackout in winter (since WonderWatt will over-supply if needed because of the higher “baseload” entry), but not so high that you block summer solar. 3. How to use it day-to-day Summer: Baseload = 14 kWh/day Min SoC = 40/40/30 % → Battery charges just enough to cover overnight + poor solar days, but leaves headroom for PV exports. Winter: Baseload = 46 kWh/day Min SoC = 40/40/30 % → WonderWatt interprets the higher baseload as extra demand, so it fills the battery harder in cheap slots. On really cold days, you’ll still want to run the ASHP directly during cheap windows (slab preheat). This gives you: Only one SoC preset to paste in WonderWatt, Just flip the baseload entry (14 ↔ 46 kWh/day) when seasons change.

Add the two statements together you have your answer. There isn't enough use of the grey matter going on. If they can't get it from the local plumbers merchants - not much chance it will happen.

This what you need, https://amzn.eu/d/21zDWZQ

I do have a slight anomaly in that I can generate more than I can export, on a good day I can generate at a rate near to 6kW, but the system will only export 3.6kW. So charging fully in summer may not yield the best. My thoughts are to continue with solar forecast battery charge, to allow self use as much as possible and excess PV export. But change the settings in the immersion diverter to only start immersion if battery is at above 99% charged AND I am generating more than 4-5kW (need to calculate setting). The likelihood ASHP will be ticking away doing cooling anyway and background house hold demands take car of the rest. If I am generating less than 4-5kW keep immersion off. The other option is to simply set an export window (afternoon say) and export everything when battery is above say 70% (again need to calculate this figure) if I am generating 5kW, 3.6 will be exported the rest will go into battery. Think I prefer this option now I have written it down.

Welcome. Think your installer is talking sense. First alarm bells So you are not letting it run and find it's feet. Stopping the heat pump makes it run when restarted a little strange. Firstly it trying to get itself back to target flow temperature, for this it monitors return temperature and delta between flow and return. All these are managed by the controller. So it you have a decent sized buffer and healthy demand on fan coils it never really catches up. The other alarm bell Most fan coils have a design temp of 7 degs that's how they are sized. To run warmer temperatures in cooling mode that need to be big and sized to suit a higher flow temperature. As you only have two to cool or heat the whole house I doubt they would be as big as needed. Once up and running in steady state conditions the heat pumps will modulate to suit the demand. Just because it's rated at xkW doesn't mean it spits out that all the time. Mine kicks out 6kW and over the last 48 hrs has consumed just over 3kW including DHW, because it has no demand, cooler weather and no solar gain. Are you monitoring with a heat meter or something else? Hope this helps