Knowing How to Choose the Right Products

We have
installed solar systems on a sailing yacht, a camper van, and a large houseboat – originally a tiny house and now the equivalent of a small off-grid house. Our suppliers mainly did not ask us the right questions, and therefore we made a number of expensive wrong decisions. Our aim is to help you better understand your needs, and avoid the mistakes that we made by encouraging you to ask yourselves some key questions before buying anything from us (or indeed elsewhere!).

Some questions are common to ALL off-grid solar installations, but some are not. This first “Advice” post deals only with the questions that always need answers. We will be adding “Advice” posts specific to each market sector in which we are active:

• sailing yachts;
• narrowboats;
• widebeams;
• river cruisers;
• houseboats;
• camper vans;
• tiny houses;
• off-grid houses

The Basic Questions
Relying on an off-grid solar system usually imposes constraints. Heating and cooking mostly cannot be electric, and you need to think about your electricity usage. The first question you must ask yourself is “How much do I consume and when”? During daylight your solar panels will usually cover your power needs, except, perhaps, on exceptionally grey winter days. For users where this is relevant, you can (and should) choose to run appliances like dishwashers or washing machines during the day. All off-grid solar systems must have batteries to store the electricity needed after dark. Fridges, and internet boxes are always on. You also need lighting even if it is all LED. In winter it is dark at 17h and not light until 9h the following morning. That is 14 hours! Before you start you need to know:

1. Total average daily electricity consumption?
2. Electricity consumption after dark?

You also need to consider how much is the maximum amount of power that you are going to need at any one point in time. Appliances needing heat use enormous amounts of electricity while they are on. Toasters, coffee machines, dishwashers, micro-wave ovens are all examples of high draw appliances using around 1Kw or more while in use.

In the next post, we will consider what your answers mean for

• solar panel,
• inverter, and
• battery capacity