Charge controllers using relays or PWM type? The little white shapes you can see on this photo below are wind turbines on Scoraig in 2011. I went to school in Edinburgh, and university at Cambridge before arriving on Scoraig in 1974 with a desire to get back to hands-on basics. Life was basic then, but in 1978 I decided to build a windmill like a couple of my neighbours to provide electric lighting in the crashing winter storms.
It took me a whole year before I got something that worked reliably, and after that the neighbours all wanted one too. I was hooked on making windmills, and it turned out that I was better at that than I was at growing veg. There were lots of problems though, due my inexperience and the wild nature of the wind as an energy source. I used to take car batteries down to the windmill, charge them and wheelbarrow them back to the house much as they do in the developing world. A tiny bit of electricity is quite a lot more precious than all of the rest that comes later.
After ten years of doing this stuff alone, climbing up scaffolding poles and wiring up home-made electronic controllers, I decided to go on a windpower course at CAT and learn to do it properly. They told me that I could come for free, but unfortunately I had to teach. That was fun, and it turned out that I was better at talking about windmills than I was at making them. Since then I have taught there a couple of times each year.
Throughout the 1990s I expanded my horizons, working with wind turbines that were built in factories and was surprised to find that they also seemed to be just as unreliable as my Scoraig-built ones. It’s a well kept secret in the small wind industry, but windmills do tend to go wrong. Maybe that’s why I love them so much. Don’t make a wind turbine to save money! It’s much more likely to take over your life. Also around this time I built and documented a windmill based on the brakedrum of a Ford transit van, took it to Glastonbury festival and talked to people.
Permanent magnets were just beginning to become affordable and I was able to move away from using old dynamos out of military jeeps and buses. The DC dynamos were well made, but their field coils used up all of the power in light winds, whereas permanent magnet machines did not need power for their magnetic field. Here is a part of my brakedrum windmill plans of 1993, explaining how I made the stator. I did not have an Apple Mac in those days. I was also doing some hydro power installations using induction motors as generators, mostly on the Isle of Eigg.
I was amazed by how much easier it is to make a reliable hydro turbine than a wind turbine. It’s a pity there is so little reliable flow of water on the Scoraig peninsula, so we have to rely on the wind. Sri Lanka and Peru, helping them to make permanent magnet alternators for small wind projects. I still like them best to this day. It was about ten years ago in 2001 that I started to teach courses in which we actually built a wind turbine and erected it. I would say that these have been the most fun things I have done in my life. You can see some photo diaries and videos listed on this page.