The Ultimate Guide to the Different Types of Off-Grid Solar System Setups
The Clean Energy Council have put out interesting facts relating to the use of solar as a viable energy source in Australia. More than a quarter of all households have some form of rooftop solar installed as of December 2020, and over 3 Gigawatts of power are added each year. Figures are even more convincing for medium and large-scale solar setups in schools, malls, hospitals and commercial buildings. Renewables account for almost a third of overall power production (32.5%), and roughly a quarter of that is generated by small-scale rooftop solar.
The uptick in renewables, and solar in particular, extends to areas other than essential grid-connected power. Off-grid solutions are also being rapidly snapped up. Our love of the great outdoors means we want and need power even when far from home. Whether out hiking, camping, fishing, taking a few pics, or planning a longer trip around the country, a solar setup, big or small can power all devices and appliances.
Portable panels keep smaller power and larger battery banks topped up no matter how far you are from a mains connection. This will power smaller devices like phones, cameras and laptops, or larger appliances like off-grid fridges, ovens, and aircons in campervans and motorhomes. Before setting out to buy portable solar panel, there are considerations as to the type of panels, how they produce energy, their installation and pairing with other gear, as well as overall energy needs.
Portable Panel Types
Buyers have a choice of three types of portable panels – hard-frame folding panels, and solar blankets and mats. Here rigid frame panels are the older type, consisting of two separate banks of cells, enclosed in a thick aluminium frame and sheet glass front. Though the folding mechanism reduces space, these are heavy and cumbersome, and somewhat impractical.
Solar blankets do away with the weight of metal and glass, instead of arranging multiple configurations of bank cells in reinforced polymers and within a canvas outer. Weight is considerably less, meaning they’re easier to transport. In addition, high flex translates to less space and easier folding. The only downside is ideal placement.
This issue has been rectified with the newest type of portable panels – solar mats which combine the rigidity of hard-frame panels and the flexibility and low weight of blankets. Mats consist of several banks of solar cells, coated in the same hard-wearing polymers and canvas lining as blankets, but arranged around a semi-rigid baseboard. They fold out in one direction meaning better rigidity in placement, and adjustable in-built legs let you capture sun rays at ideal angles, so efficiency is also improved.
Producing Usable Energy
All Photo-Voltaic (PV) panels consist of semiconductors that absorb sunlight in the form of photons and generate a flow of electrons, basically electricity. This is converted to usable power with a solar charge controller or regulator. Some panels have these built in, while blankets and mats mostly come with external controllers.
The role of controllers is to provide optimal charge to the battery, based on the current charge level and the type of battery. It also protects the battery from overcharging and overheating, and prevents the charge from feeding back into the solar cells in what is known as reverse polarity. As well as protecting and prolonging the lifespan of expensive deep-cycle batteries and panels, a decent charge controller can also mean faster charging times – good if you’re constantly on the move. For more on solar charge controllers see here.
Smaller portable solar setups function perfectly well with PWM regulators, whereas larger (rigid) systems, with multiple panels and batteries, are better served with uprated MPPT controllers. When looking to buy a portable solar panel, blanket or mat, consider getting an inexpensive controller to safeguard your investment in other gear (notably expensive Lithium-ion batteries).
Batteries, Cables and Other Gear
If you’re camping out of a campervan or motorhome, where there are multiple power-hungry appliances, then go for a high-capacity lithium-ion battery. For larger vehicles and larger solar installations, this might mean that you need multiple batteries connected in a battery bank. But for occasional camping, a much cheaper AGM battery is perfectly fine, and will power most of your stuff.
Portable solar panels are often packaged with everything you need to generate power. Cabling connects panels and controllers with batteries with included alligator clamps or Anderson plugs. Look for longer cables so that you can place panels, mats or blankets in direct sunlight, while having your vehicle parked in the shade. Convenient carry cases allow for easy transport and storage and keep your portable solar kit protected.
What to Look for in Portable Solar Panels
For higher charging efficiency look to panels with monocrystalline solar cells and ones that have been certified as ‘A grade’. Materials should be top-notch, especially the canvas in solar blankets and mats. Ensure that this is waterproof and can resist tears and damage in heavy-duty use. The same goes for the materials in the legs, and the tie-down pegs that keep mats and blankets stable in gusts.
Panels, mats and blankets differ in total power output. A 200-Watt solar mat should provide enough power for most campers. More demanding users can combine several panels or mats, along with fixed panels on the vehicle in a dual battery setup. Before buying a portable kit, make sure that the regulator is compatible with your type of battery.