A good day in terms of mileage, supported by a strong following wind for a change. However sun was very limited and I literally limped under Wallingford Bridge praying for a last push from the batteries to drive me against a strong current. But happiness at the end of the day with a secure boat mooring and a secure personal mooring in a hotel bed.
It was great to meet with John Powls at Goring and Mark Brett and his family at South Stoke.
Sunday morning is overcast and bleak; what more could one expect for the day of Wimbledon Finals and the British Grand Prix. Given the family motto - 'Press on' - it is hard for me to accept the limitations of the weather and pause the journey. But in reality I have exceeded my expectations on progress and should not be pessimistic. What has become very clear is that with average amounts of sunshine the solar formula does work for a small boat willing to proceed at a modest speed. With the improvements in solar technology round the corner added to improvements in battery capacity, then it will not be long before solar boating becomes more 'normal'. A few technical facts below!
Techy Corner - Propeller Heads Only
Each solar panel on Corvelia is rated at 80 watts maximum output. These are linked in pairs to charge each battery (see Day 7 for more technical details on the batteries). In theory this means that at around midday when the sun is overhead I could get 160 watts of power for each side which converts to 13 amps (Watts = Volts x Amps). In practice I get about 10 amps maximum. If the solar panels could be moved to point at the sun then I could keep this level of charge for more hours in the day. Alternatively the glass covering the panel could be made of small prisms which optimise the collection of sunlight and focus it on the photoelectric (or more correctly photovoltaic) cells that make up the panel; I gather this is one innovation on the cards for the near future.
You can get lightweight 'amorphous' solar panels, of the type used in calculators; but these need a much larger surface area for the same power as the heavier crystalline panels I am using.
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