Where to begin

7:00AM and I’m not long up, the wind shifted to the north west during the night already it’s heralding a better day ahead with a steady stream of fishing boats heading north along the Skye shore. I guess they’ll be in the lee of the land for shelter. Sundays steady near gale force westerly may have veered and eased but it’s still quite lumpy out there. I may still be sat in my PJ’s not even having started on the strong black coffee that kick starts my day but I was up at 3:00AM The wind being so steady and constant that I wanted to put a long hot wash on to do my towels to put an immersion on for a couple of hours. That done and with my turbines still milling away I went back to bed to finish my well earned sleep. The Sabbath had been a busy one  https://www.wunderground.com/dashboard/pws/IKYLE21/graph/2022-02-20/2022-02-20/daily

Air locked

The wind mean speed being 25MPH for day with gusts of double that. Added to that the frequent sunny spells and showers had given me the ‘perfect storm’ for energy production. So, after feeding the pigs Bonzo and I went to check out the Powerspout and turn on it’s second nozzle. The penstock must have had air in it when I commissioned it Saturday cos this morning its output as indicated on the Victron 250/60 MPPT controller was almost double what it had been when I started it.

 

The image on the left showing 51V at 3A (153W) and the one on Sunday morning 53.5V at 7A around 375W. I guess that the penstock had been turned off for so long it must have had air in it somewhere down its 250M of pipe. Anyway I couldn’t wait to go and investigate with the wee dog.

   

First stop was to check the forebay and inlet before going down the overgrown path to the turbine shed by the shore.

  

The tide was pretty high with the sea almost cutting off apiece of land opposite the shed and turning it into an island.

 

Upon entering the ‘turbine house’ the first thing I noticed was the almost doubling of dynamic head on the pressure gauge, even with both jets open it was now reading

54PSI or 3.7Bar as opposed to 28PSI or 1.9Bar on start up  

Sure enough once back up the ‘power station’ the output was a far healthier

 

15Amps or almost 775W

Mr Lister is flat

After that we collected Molly from the rear of the Land Rover and went in for a well earned breakfast before heading over to Torran with mail and parcels to give Mr Lister a run.

  

I’d a feeling that Mr Lister wasn’t going to start, which turned out to be the case, his batteries had gone flat and I had to use the handle. However the ST2 Startomatic burst into life easily and my meter indicated he was charging OK. The Lister ‘Start O Matic’ is designed to start automatically one you turn on a load (around 60W). It will then continue to run until everything is switched off and the load reduces to below the 60W threshold and it does all of this without a single chip or PCB. Being designed in the 50’s it does it all with relays, coils, contacts and solenoids. It’s a very reliable system if not a little ‘agricultural’ however the battery charging circuit is a little basic and designed for charging the batteries over long periods of usage. You have to bear in mind these units were designed to run 12 hours a day 7 days a week and for that it is perfectly adequate. Consequently if left unused for long periods of time without disconnecting the batteries they tend to go flat as there is always a slight current in the ring main. So after firing him up I went back home to get a serious charger and left him running.

Running repairs

With all the rain lately the Torran track has been getting into a bit of a state so during my trips to and from the Schoolhouse I put a shovel in the back of the Mule. A trick that the Council roads department would be wise to emulate when they often send a 7m long empty pick up truck over to Raasay to read the Sun. At least that’s what they appear to do A few strokes with a shovel to get the water off the roads would go long way to reducing the need for repairing potholes.

    

Too much power

Despite my best efforts to use all the electricity I’ve been making by washing all the towels, bedding, leaving all the lights on tumble drying everything. My ‘dump loads’ have been doing overtime, making my bunker and power station very warm. The ‘dump loads’ are wire wound resistors that dissipate excess electricity as heat and I have a lot of them.

   

Around 10kW in the ‘power station shed another 11kW in my workshop

and around 8kW in the bunker.

   

The two in the bunker comprise of that big silver box which contains the 6kw wind turbine dump and that wire wound resistor at the base of it which isn’t really big enough at 1kW. It should be around 2kW but it was all I had at the time and the new ones I’d ordered before Christmas from Farnell https://uk.farnell.com/te-connectivity-cgs/te1000b1r0j/resistor-1000w-1r0-5/dp/1760846?Ntt=1760846 were on back order. Well they finally arrived the other day so I fitted them last night.

These resistors providing a welcome boost to my air source heat pump who’s inlet is right above them

https://scoraigwind.co.uk/using-a-high-power-resistor-as-a-dump-load/ All you ever need to know about ‘Using a high power resistor as a dump load’ is contained in Hugh Piggott’s excellent blog.