Being shocked at the rise in fuel (and therefore energy) costs, I set about understanding what I could do to insulate my family from the effects of this bull market on oil.

 

I dabbled initially with wind power (and I may yet return to this). But several design attempts (2 styles of VAWT) and alternator designs led me to believe that the amp hour capability of homebuilt designs are not worth the ground space. I never achieved much more than 0.2Ah generation, and the safety aspects were less than optimum, even for a VAWT design. Both designs were however, totally silent.

 

So, notwidthstanding a factory built alternative, solar power gives far more energy per square meter than wind, and is more reliable - ie. its light generally more than it is windy - even on Mersea. And remember, the average wind speed on Mersea is 6mph, and most wind generators only produce significant (> 4A) current for charging at much higher windspeeds.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

This design, spun up at really low wind speed, but could only turn a small stepper motor - it generated approx 0.2Ah.

 

So solar really was the way to go, with most panels giving some charge even on cloudy days (generally not so much - between 1- 2A). My aim initially was to charge a battery bank and store power to run a small immersion (12v) heater installed in my hot water tank. However, to run this (200 Watt) heater takes approx. 16A of current per hour - so to warm the water from cold takes about 3-4 hrs (16 x 4 = 64Ah). The heating element is on the small side, so really there is enough hot water to do the washing up. Still, its early days. In earlier tests, when I ran the immersion heater via a 12v transformer from the mains, if left on for 24hrs, would keep a fair amount of water hot, but the charge needed to do this would be 16Ah for 24 hrs, 384Ah. The battery bank is sized at 510Ah currently, but the batteries should not be drained beyond 50% of their capacity, lest damage occur, which means the effective capacity is 255Ah. As I add more solar panels, then it may be come feasible to run the hot water through the day and have enough charge left over to charge the batteries. The heating element takes around 16 Amps at 12v, so the panels should supply in excess of 16 Amps. I have extended the mains supply cable from the garage so I could disconnect the mains, and use purely off grid power ( assumes I up the panel wattage to 1500 and use a 3KW inverter - I’d add another 4 batteries to the bank as well).

 

This in conjunction with a diesel generator (3.5KW) could allow the household to run off grid, with some common sense power management. The Genny would be used where several days of overcast weather meant the charge in the batteries was lower than is safe for them, so the Generator would replace the inverter and supply household power, whilst simultaneously charging the battery bank.

 

Use of a diesel generator allows a wide choice of fuel options. That man Diesel was a smart cookie. His initial demonstration of the technology to the world back in the early part of the 20th Century, used peanut oil as a fuel. The diesel engine can use pretty much any oil as a fuel. So, for the sustainability minded, rape or sunflower plants could provide fuel for overcast days.