Ronski

I've had to contact UK power networks a couple of times over the last decade as our voltage went above 253v, but this was usually very early in the morning (my UPS records this info), when there was very little demand and of course no sun. The lady that visited last time told me they have to change the transformer tap twice a year to allow for the solar in the summer. PS. What's the power factor box for on the G99, no idea what to put in there?

Thanks both, I'll fill out the G99 and see what happens. Don't know if it makes any difference but we are right next to the one of the estates two substations - an 11kv transformer. I bet that 540w panel will be large and expensive though?

Thanks to all those that have replied, have only just seen the replies as I didn't get an email notification - I'll have to find that setting. To answer some questions/suggestions in no particular order. We don't have a hot water tank/immersion heater, it was removed circa 2005 as gas was cheaper for heating, so a condensing combi boiler was installed. Shifting large loads, large loads are only washing machine, dish washer and electric oven, we both start work early, so washing/dish washer tends be go on to suit our work schedules, so its only really weekends we could do that. We have a tumble dryer but it is very rarely used. Most of the power usage is an always on server and other computer equipment such as networking stuff, two fridge freezers. How do I envisage the batteries knowing how to charge, well I've been wondering just that. The solar arrays connect back to the CU, the AC coupled batteries connect to the consumer unit, but how do they know to charge/discharge? I thought perhaps they use a CT clamp to measure flow of power in/out to the grid, but that would only tell you how much, not which way it flows, so perhaps some other measuring device is used. Any body know what the correct answer is? I've worked out what the arrays will likely produce using https://easy-pv.co.uk/ but I don't understand the shading/sun path bit works, so both have a shading factor of 1 Garage with 12 x 415w panels is an estimated 5174kWh annual output (15 degree pitch) N/W roof with 13 x 415w panels is estimated at 4370kWh annual output I was also looking at sending a G99 application, but obviously have no installer at the moment, can I just put TBC for the installer section? Actually do I even have the correct form - see attached? Best I get to bed, its late. G99 form.pdf

We currently have a 4kw Solar Edge system installed on our house roof in sunny south east Kent, which was installed in 2015, so earn reasonable FITS from it. We have a detached double garage with flat roof, which is 5.7 x 5.93 meters south westerly facing, dependant on spacing of the panels we could fit at most 12 panels on it. There are two tree's that would cause early morning and late afternoon shading, which is obviously worse in the winter, but for the main part of the day it is unshaded and gets direct sun. We also have a large NW facing roof at 30 degrees pitch, where there is room for at most 12 - 14 panels, there is also a chimney that would cause shading, and possibly next doors roof, but the roof shading would be close to the end of the day anyway. We would like to add a solar array to either the garage or the other roof, and also a decent sized battery, without an additional array, there won't be enough solar except on very good days to charge a decent size battery. Requirements: Additional solar array on the double garage or NW roof Decent sized battery – either in the garage or the house Able to use excess from existing array to charge battery Able to charge the battery from off peak electric when solar production is poor Whole house battery backup would be useful, although not essential (a nice to have) - see notes below Existing power usage. We use 10,000kwh a year (includes what we use from existing solar) We generate on average 4350kwh a year, and export roughly half We don’t have an EV, and currently no plans for one – too expensive to buy - our cars are old, but bought and paid for, not leased. I've got quotes from quite a few companies (still a couple to come, but they are busy), they either come in expensive with poor system specs (£9250 for 9 x 370w panels & 2.4kWh battery) to systems that use DC coupled batteries, and therefore wastes the excess power from our existing array - I would be correct in thinking we need AC coupled batteries to use the excess electric from our existing array wouldn't I? Another complication is that I think we need planning permission if the panels exceed 200mm in height from the roof of the garage, is that correct? Our existing array uses optimisers, and given the shading on either of the two roofs, I feel this would be the way to go, but obviously complicates things. Our house is split in to three ring mains + the garage, the kitchen and utility room are on there on ring, so all the juicy appliances could be disconnected easily when on battery backup so not to risk overloading the inverter. As you can see from my introduction post I'm quite capable, but I am not an electrician, ironically when at school many many years ago that is the trade I wanted to go in to, I did a day release college course, even work experience, but couldn't get a job when I left school as a trainee and ended up being a mechanic instead. So I'd like to do the labour intensive side of the install, but have an electrician, preferably MCS registered to do the electrical work and over see the system design. So what's peoples thoughts?

@ProDave Thanks, but I would happily pay for new 400w panels, as I only have room for 12 panels at most on a flat roof double garage, or maybe 13 or 14 on a less than ideal NW facing roof with a chimney to cast a shadow. The best roofs already have a 4kw system on installed in 2015. Probably best if I start a thread. PS. Looks like some useful info on there, and they are not that far away, around 100 miles or so.

I've been getting silly quotes from companies, either silly prices for rather lacking systems, or reasonable prices but just doesn't do what I want. The last one specified a DC connected battery, and when I asked if the excess power from our existing array would charge the battery the answer was no. Well I knew that because you need an AC coupled battery to do that. I'd like to install my own system, and use an electrician to the electrical work, preferably MCS registered, but the chance of finding a willing one is extremely unlikely. So anyone know a good electrician in the south east - I'm in Broadstairs?

Hi all, I'm not building a house, although I did design and build a rather large (by my standards anyway 😉) extension in 2004, had a builder do the shell to water tight, then I did pretty much everything else where possible, which would explain why it took well over a decade to finish. Here's a link to my cinema room, and some other things which I included in there - such as installing goal post steels and 3.2 meter bi-folds, which just my brother and myself installed. Anyway signed up here as there seem to be some very knowledgeable people that know quite a bit about solar and batteries, so I'll start a thread in the appropriate section for that.