We have a surprising amount of keen boaties in our office, and we are lucky enough that each year we take part in the Architects Regatta, which is always a highlight!
Lyn has put together some info about her solar powered boat!
We are a family of keen sailors, and a couple of years ago we purchased a classic New Zealand designed yacht – a Des Townson Talent 34 - constructed of double diagonal kauri and with a beautiful mahogany interior. It came with added luxuries not often seen on boats this size – an electric fridge, electric freezer and an electric toilet. However we soon found that these luxurious features had a disastrous effect on battery life, meaning we sometimes had to make a choice between using the fridges and toilet or being able to start the motor!
To remedy the situation we had two options - convert back to a manual pump toilet and compressor driven fridge (involving running the diesel engine at regular intervals to keep the fridge working) or to investigate alternative energy sources. The idea of solar power was appealing and after considerable research we set up the system with two 100 watt monocrystalline solar panels supported on a chrome plated steel frame which also serves as a sunshade and a handy place to store our dinghy.
The solar panels are connected to 2 x 250 ampere hour house batteries which store the power to run the refrigeration and the toilet. Another 100 watt flexible solar panel on the deck provides charge to the 105 ampere hour start battery, which is also charged by the motor when it is running. A solar regulator monitors the charge and switches excess capacity between the two systems as necessary to avoid overloading the batteries. Of the 500 a/h storage available in the house batteries, only 80% is available for use, so the house system provides us with 400a/h, which typically runs down to around 350 a/h at the end of the day. Storage is usually back up to 400a/h by 10am the next day, regardless of the weather.
While we initially set up the system to solve a problem, primarily to ensure that we could start the motor at any time if needed to avoid a dangerous situation, we very happy with the additional benefits. We can now count on being able to reliably start the motor, but do not need to waste diesel running it to chill the refrigeration system. We can run both fridges constantly while on board without fear of running out of power and have plenty of capacity to keep food frozen (even ice cream!) or cool, in contrast to the diesel compressor system where the food is usually either frozen or warm! We don’t have to be sparing with turning on the lights or flushing the toilet! It’s quite hard to get used to the idea that running electrical appliances is not costing us any money..
The success and the ease of running of this system has made us enthusiastic advocates for solar power – next project will be to install it on the house!