Having used a generator to power their holiday home near Tortosa for many years, Leon and Gerda recently decided to upgrade to solar; approaching Clear Sky Solar to design and install a suitable system to power their home, removing the need for a noisy, expensive and polluting generator.
The brief was to provide a cost-effective solution that would be reliable and simple enough to work first and every time when the family arrived for a holiday. It would need to power the water pumps, washing machine, lights, internet and all the other appliances including the all-important coffee machine.
As with every installation – our first step is to complete a Solar Generation and Storage Calculator. This calculator takes all of the predicted loads and calculates how much power each system will need to produce each day, in each month of the year. From these results, we can start to plan what size inverter, solar array, charge controller and battery we will need to cover all expected requirements.
After looking at all of the potential loads, and the brief as a cost-effective system for a holiday home, we looked to the new Outback SPCiii inverter/ charger. This all-in-one unit combines a transformer-less inverter/charger with combined solar charger controller in a single neat unit – in three sizes: 1.5kVA, 3kVA and 5kVA. To fit with the calculated peak load and consumption, we decided on the 3kW @ 24V unit.
One of the great features of the SPCiii is a high open-circuit voltage (Voc) for the solar input – more in common with grid-tied inverters than standard off-grid charge controllers. This means it’s possible to connect many more panels in series than a standard off-grid charge controller – reducing the costs of cabling and installation for multiple parallel strings of panels as in a conventional off-grid system.
To supply the required solar power, we decided on a single string of six high quality German-manufactured Luxor 330W, 72 cell solar panels – giving a peak power of 1.9kW.
We had a number of options for siting the panels: in-plane with the house pan-tile roof; on a ground mount on one of the flat terraces; or on the flat roof of the garage. After calculating the potential solar inputs for each option, we decided on a 30deg pitch aluminium frame fixed on the flat garage roof.
The final decision to make was for storage: calculating the clients’ battery requirement, four 6V, S550Ah Rolls batteries were installed (in series to give a 24V battery) – giving a useable 6kWh of storage – enough to give autonomy of 2.5 days of grey days – plenty for our sunny corner of Spain, and removing the need for a generator.
As with every installation, suitable earthing, distribution and protection was included, to protect both the system and the users, as well as a reworking of the AC circuits to fit with the new system.
- Outback Energy SPCiii 24V inverter/ charger / charge controller
- 6 x Luxor 330W solar panels on a 30degree aluminium frame
- 4 x Rolls S550 6V batteries
- AC and DC breakers, earthing system
- Back-up generator, 3kVA