1. What components make up an off-grid solar system?
The basic components are:
– solar panels, with a suitable method of mounting
– a suitable battery
– a charge controller to link the panels to the battery
– an inverter to convert DC power from the battery to AC power for household use
– an AC charger to charge your batteries from an AC source such as a generator
– protection: suitable breakers, earthing and cable to ensure maximum safety
Often some of these components are combined in the same unit; for example, most inverters will also act as an AC charger.
Some smaller, more cost-effective inverters also include a charge controller in the same box, known as all-in-one units, and just need solar panels, breakers and a battery connected to provide power.
2. How much does a solar system cost?
Every case is different. We always design systems that match your requirements and budget, and produce a quote following a site visit.
However, as an approximate guide, our most cost-effective complete system, installed, is in the region of 3,500€. This includes panels, mounts, ‘all-in-one’ charger-inverter, and battery system with all necessary protection and cabling; and would be suitable to power a casita year-round.
A comprehensive residential system – based around market-leading Outback Power equipment of a much higher capacity – would be in the region of 12,000€ – 20,000€. This type of system is capable of powering one or more buildings, with little need for a back-up generator.
3. How long will my system take to install?
This all depends on the scale of the system. For a smaller all-in-one system, after accepting the quote, delivery of equipment can be done in two to three days, with installation then taking one or two days.
For larger, more complex systems, installation typically takes around two weeks on site.
4. How long will my solar system last?
Most solar panels we supply are designed for a minimum of a 25-year working life. Outback products have a warranty of five years and will continue for many more years if used in a properly designed and maintained system. Battery life is dependent on the technology used and the depth they are discharged; but can easily be 10 years usable life from a lead-acid 2V cell system.
5. What are your payment terms?
We invoice for equipment prior to installation, paid before delivery, with a final invoice for installation and labour following commission.
6. Do you have insurance?
Clear Sky Solar has all necessary insurance and is fully registered for solar engineering work in Spain.
7. How many solar panels do I need?
The number of panels depends on several factors, including:
– Insolation: amount of sun hitting the area
– any unavoidable shade
– daily load, or power consumption
– battery size
As an example, a standard family house with the usual household appliances might have 15 panels and generate enough power year-round that a back-up generator might only have to run one or two times in a year.
8. What size inverter do I need, and what can I power with it?
In an off-grid system, the inverter needs to provide every Watt of power, so when designing your system, we need to consider the worst-case-scenario – when all loads are switched on at the same time.
A small family home might work well on a 3kW inverter, powering lighting, fridge, TV, laptops – and when the sun is shining – a washing machine or small pool pump.
If you need to run more appliances year-round or operate a bigger pool pump or larger power tools, a 7kW inverter would be more suitable.
For a larger workshop or pool plant, a 14kW or 21kW system might be required.
9. Do I need a back-up generator?
With a properly sized solar system, in a sunny climate such as Spain’s, the need for a generator is rare.
With the cost of solar panels coming down so dramatically in recent years, our advice for a standard residential install in a sunny location is to save the cost of a large generator, purchase a small back-up generator that can provide emergency power, and invest the savings in a larger solar array.
Even on grey days solar panels still produce some power; increasing the size of the array means it’s entirely possible to power a house and charge the batteries even when the skies aren’t completely clear.
10. Where do the panels go, and how are they mounted?
In more urban areas, panels are almost always mounted on a roof. However, most of our off-grid installs are in the countryside, where there could be ample land to use ground mounted arrays, which allow more flexibility in location and angle. Of course, if there is a suitable roof, we’re more than happy to mount on there too.
See the case studies for some examples of mounting systems and the blog post describing the effect of angle and pitch.
11. What types of batteries do you install?
Battery technology is changing rapidly, and new technologies are coming onto the market all the time.
Traditionally, for residential installations, multiple 2V lead-acid cells are connected to create a higher voltage battery. This is an older technology and requires some maintenance but can be very good value if treated properly.
There have been various adaptations to the traditional lead-acid battery, designed to remove this need for maintenance, such as gel or AGM. For small installations, for example a small holiday casita we often install smaller gel batteries, due to their safety and zero-maintenance.
Lithium-ion technology is advancing at a rapid pace, and affordability is improving every year. There are huge advantages to lithium-based batteries – a high level of safety, zero maintenance, and a great lifespan, even when discharging the batteries to a very low level.
12. Can I add increase my system capacity in a year or two?
Over time, you may find that your circumstances change and you need to expand your system, possibly as more loads are added or as more budget becomes available. We always try to anticipate this from the start and design systems in a way that can be as flexible as possible in future.
– It is always possible to add more solar panels, sometimes via additional charge controllers, into the same battery.
– Adding to a lead-acid battery isn’t advisable; after a while, the original cells will limit the performance of the new cells.
– Depending on the specific type, lithium-ion battery manufacturers state that it’s possible to add extra storage (within limits) without any loss in performance.
– Many brands of inverters can be linked – or stacked – together to create a larger inverter. For example, two 7kW Outback Radian inverters can be stacked together to create a single 14kW output.
13. Do you maintain solar systems?
Yes, we always keep in touch with our clients after the installation. As each system has a settling-in period where -especially for the more complex systems – there are parameters in any system that can be adjusted to best suit the requirements. This is greatly helped by using Outback’s remote monitoring system, Optics RE.
We are also happy to provide individual components, maintenance or repair for existing systems.