billi wrote: ↑Sun Jul 10, 2022 11:23 pm
like me , Kris ,did the mistake to built up an off grid idea based on 24 volt battery bank
the setup of that 4 kw PV as it is clamped down to that 4 KW as he explained , would be much more interesting to discuss, than the mounting frame and setup of that PV and the "beautifull timber construction" that needed him 5 weeks to built (hope he did no full days work on that ) , surely his cost calculation/result of 7-8000 GBP for that install , is based on free timber and free labor . But put that into relation for people to get an contractor in, to install it that way ..... the costs would be astronomic ! and in no relation to the clamped 4 kW of PV
Obviously he had not have the possibility with his setup, to use an Grid tie inverter for AC-coupling , or did not think about it
Surely some MPPT charge controllers can handle an oversized PV array like some of the Victrons and the Midnite classic that he has got too . And both of them can "only" handle a limited amount of Amps to a battery voltage , and therefor this 8.4 kW PV is limited to 4 kW as he explains .
As we know that he has a workshop with powertools to run etc , the AC-coupling idea perhaps would have been a better idea . .....
But lets admire the beautiful timber frame
He is way off grid, high up in the hills in South Wales, not far from the Lammas community in north Pembrokeshire I believe (he did mention in one video that he's been a volunteer at Lammas). He has no mains electricity supply, no mains water supply and no mains drainage. The notion of any sort of grid tie system is therefore not applicable as there is no grid to connect to.
I don't know for sure, but I suspect he's taking advantage of the "one planet development" law in Wales that allows people to build homes in rural areas as long as they can show that they are largely self-sufficient after 5 years and are not doing anything to damage the environment. This was the law that was introduced after a great deal of work by the Lammas community, and I still find it remarkable that the Welsh Assembly was forward thinking enough to introduce it, even if they did need a lot of persuading.
The background to his story is that he got fed up with working hard at a normal job, saving, buying a house etc, so sold up and bought about 18 acres of very poor farming land and woodland. He camped on that land in a tent for years, built himself a single room round house using mostly materials from the land, and as he's learned more about natural building and off-grid living he has built better stuff to make life more comfortable, like his home made wind turbine, home made hydroelectric installation, and his original home made PV system.
As he's learned new skills, and been able to earn some money by teaching others about what he's learned, he's made their home more comfortable and practical. The thing that impresses me the most is that he just gets on and does things without assuming that to do them requires some secret trade knowledge. He does the research, understands how something needs to be done and then just goes and does it, pretty much always to a high standard. For example, his first round house was built with him knowing it would not last forever, IIRC he designed and built it to last around 10 years, giving him enough time to learn the skills, and gather the resources, to build a more comfortable home.
Same goes for things like the massively over-built greenhouse he designed and built. The timbers are way bigger than would be typical for an off-the-shelf commercial greenhouse, but he designed it to cope with the 50mph to 60mph winds they get in their exposed location and also he wanted it to last at least 30 years. The same design logic was applied to the ground PV mount - it has been built to both withstand the high winds at the site and to last at least 30 years.
There is a lot to be said for massively over-building something when you rely on it for much of your power, it is your own hard labour going into it, and when you have a source of free timber and a home made mill to provide any size you want just for the cost of the waste vegetable oil that runs the engine. I do the same, as I get older I don't want to have to worry about something failing and me not being fit and able to repair/replace it, so I make stuff that will last longer than I will if I possibly can. If his PV system fails during a dry and windless period then they have no power until he fixes it, and I'm sure that influences his thinking when it comes to making the thing reliable and long-lasting.
25 off 250W Perlight solar panels, installed 2014, with a 6kW PowerOne inverter, about 6,000kWh/year generated
6 off Pylontech US3000C batteries, with a Sofar ME3000SP inverter