Should I go off-grid?

HertsLad

70sbudgie said:

HertsLad said:

Ectophile said:

HertsLad said:

A named storm was due but hasn't yet arrived. Strong winds are rare in Hertfordshire and might just provide useful power but it seems too unpredictable. Nevertheless, my most recent thinking was to play around building a wind tower up to 5m high with home made blades of 2m or 2.4m. This would drive either a home made generator or a car alternator with the regulator removed.

I hope you're going to apply for planning permission if it's going to be more than a temporary thing.

Of course not! I will claim it's only a temporary R&D set up, even if I leave there for months or years. My expectation, though, is that it would only produce any useful output very few times a year, when the forecast is for strong winds. So, even if I put in a considerable effort to construct it, I doubt if I will think it's worthwhile, long term.

I understand that large commercial wind turbines are geared. Given how handy you are, is it worth investigating whether the turbines you have bought are geared? And whether this would allow for optimisation?

Good idea, thanks, and one I'd considered if I make my own generator, blade and everything with gearing included. The turbines I bought are not geared but the blades could probably be separated from the generator with gears in between. My gut feel is that it might be easier to start from scratch.

Is gearing the reason why large commercial turbines turn so slowly?

70sbudgie

My turbine knowledge is very limited, so I don't know. I think that the speed is related to the size and it is actually the speed of the blade's tip that is relevant. And that it is the consistent wind speed that is needed. I don't think turbines like gusty wind.

I understand that it is the gearing that allows adaptation to different windspeeds, so adding gears would in theory improve generation across a wider range of wind speeds. (Don't forget that turbines have a max wind speed too).

Last year I did lots of research into domestic wind turbines and found a website that gave indicative wind speed ranges for areas - a bit like a wind version of PVGIS.

Qyburn

HertsLad said:

Is gearing the reason why large commercial turbines turn so slowly?

That's down to aerodynamics, even at the low speeds of 20 rpm or so, the tip could be travelling at something like 160 mph. So they either gear up to run the generator at their preferred speed range, or some (eg Enercon and EWT) make a generator suited to that slow speed so can be driven without a gearbox.

HertsLad

Storms rolled through England over the last few days with 100 mph gales and damage being talked about. But I think the south west took most of the wind. I don't believe high winds arrived in Hertfordshire, unless it was at night. My guess is that I might be able to set up a wind turbine to get some worthwhile output in the middle of a storm likely to blow over fences and trees, but not at any other time. It's my fear that I could only generate electricity for a few hours each year. which makes it seem a waste of time. Am I being over-pessimistic?

HertsLad

I managed to survive winter 2022/23 without using any mains electricity and, so far so good, for winter 2023/24. But it's not easy so I decided to buy a few more solar panels to give me more headroom over winter, and even more power in summer.  Initially, I was thinking of buying perhaps 4 more panels but when I saw how much the price has fallen, I decided to buy 10. The panels I bought between 2 and 4 years ago are approx 1.7m x 1m with a power rating of 320w. They cost about £130 each incl VAT. The latest panels are approx 1.7m x 1.1m with a power rating of 410w. They cost only £90 each incl VAT. Much better. 

I have wired up 2 panels already and the impact on recharging the batteries has been significant, even though the two new panels are currently lying horizontally and never see direct sunlight.

70sbudgie

Sorry if you have said before, but do you have a south facing wall where the new panels, fitted vertically, could catch the low winter sun?

HertsLad

70sbudgie said:

Sorry if you have said before, but do you have a south facing wall where the new panels, fitted vertically, could catch the low winter sun?

No, unfortunately not. The 10 new panels which I am buying will go on my main house roof, which faces south east. It should be great for sunlight between sunrise until about midday, throughout the year. I have 4 panels in the garden facing south at a fairly steep angle to collect winter sun and, with a small loss of efficiency, summer sun. I will be repositioning 2 further panels pointing south west, which I found is a good position to collect afternoon and early evening sun in the summer, and a bit more energy in the winter. That said, the garden gets a lot less direct sunlight in winter, compared to summer.

Going back to your wall mounting suggestion, I did make notes to consider mounting one or two panels vertically at the side of my house with some way to extend them out for less shadow (from the adjacent house). It could be made to work but would look a bit unusual and untidy compared to 10 panels on the house roof. I am sure the power collected from these 10 panels will dwarf any other position with fewer panels, firstly from direct sunlight all morning but also including indirect light for the rest of each day.

HertsLad

I was concerned to read recently of a fire which destroyed several houses in Gosport, Hampshire. The cause is thought to be a fire which started from lithium batteries being charged on a scooter. Airlines and couriers also seem concerned about arrangements for carrying lithium batteries. I now have 4 x 100Ah lithium batteries for running my fridge and freezer. They are charged every day from solar panels, and supply the appliances almost continuously. Lots of people use lithium batteries, including in motor homes and on boats. Is it dangerous and a bit risky? Or nothing much to worry about?

Netexporter

If the cells are LFP chemistry, which they generally are for leisure and home battery packs, then it is almost impossible for the battery to catch fire. The fires in scooter and e-bike batteries seem to be mainly associated with people buying batteries from dodgy sources and more often with using the wrong charger.

HertsLad

Here's another risk with lithium batteries - if they get crushed. See here: 

https://www.youtube.com/watch?v=t1j9TUV5coc