Generating your own energy needs through renewable sources such as photovoltaic panels is certainly nothing new; Consumer-usable solar panel systems have been around for quite some time and have come a long way in the last couple of decades. Many years ago, a substantial financial investment was needed to buy the necessary equipment to install an excellent solar panels system on board a recreational vehicle. Still, installing everything yourself and quickly enjoying all the benefits is possible.
When we built the living cell of our 4×4 camper to start our world tour, one of our greatest ambitions was to live independently and, as far as possible, disconnected from electricity. However, we wanted to do it without necessarily having to deprive ourselves of some comforts, let alone deprive ourselves of the possibility of exploiting some solutions that could save us some costs during the trip. Many might think that on a camper, all you need is: lighting, an autoclave pump, a refrigerator, a computer, and maybe occasionally a hairdryer. In reality, this is not the case, and there is much more to a motorhome like ours, which is designed to remain unplugged practically 365 days a year.
Having said this, it is also important to note how energy needs could increase over time. For example, someone could make improvements to their boiler and add electrical resistance, or they could decide to install an air conditioner. When designing your solar system, we advise you to use a modular approach, i.e., a method of components designed to work together as efficiently as possible. It is also essential to make sure that you use ingredients that can be installed independently to save on installation costs and maintenance costs that you will have to foresee over the years.
For this reason, when we started looking for the best products to install on our camper, we decided to find a single supplier with developments in their catalogue that could be used in a modular way and which created an ecosystem with all the components well integrated.
On our camper, we have installed four monocrystalline solar panels of 300 Watts and a couple of smaller meetings, always monocrystalline, of 150 Watts each. The Inverter, a 3000w power inverter, also performs the function of a battery charger. We have combined it with a smaller 3Kw Multiplus, which serves as a backup in case of failure of the main Quattro. There are two solar charge controllers, both MPPT and, in this case, separated for redundancy. The whole system is controlled in a perfectly tuned way by the Renogy Energy Color Control GX monitor. Therefore, we chose to install 8 GEL batteries, also from Renogy Energy, which guarantee us performance in life cycles that are slightly higher than AGM batteries. The battery bank is 24 Volt, which helps us keep the harnesses a bit smaller than a 12 Volt system.
First step: Calculation of energy needs inside a motorhome
The key to a successful solar installation in any situation or environment is to audit your energy requirements thoroughly. This critical phase of planning determines how much we consume daily and, therefore, our energy needs. To do this, you need to make a complete list of every electrical device you use on your motorhome and then separate them into 12 Volt DC (or 24 Volt DC) and 220 Volt AC. Any device powered by alternating current (domestic mains) requires the Inverter to convert the 12 V DC power supply in the batteries to 220 V AC in our case. For example, these devices are the Quattro and the Multiplus by Renogy Energy.
The next phase of energy control is to create a note next to each device, marking how many watts they use to function. The labels could also show the Ampere (A). In this case, do the trivial multiplication W=A x Volt, for example, 10 Ampere (device consumption) x 12 Volt (service battery voltage) = 120 Watt.
Attention, in this case, the approaches can be different if the camper is to be completely set up or you are installing a solar system on an existing vehicle. In the first case, you will have little choice, and you will have to rely on the data that is reported on the instructions of each device and going to estimate on paper the hours of use of each device and, therefore, the relative daily consumption. In this case, the advice is to overestimate each total by at least 30% and compensate for the Inverter’s intrinsic inefficiency. In the second case, instead, in addition to the first choice, you also have a second one: to start equipping yourself with a Battery Monitor such as the Renogy Energy BMV 700 and 702 and measure your current consumption precisely in real-time. This way, you will know exactly how much you have consumed at the end of the day.
While you’ll probably only use some of your devices simultaneously, these totals are a good guide to work from, as batteries should never be discharged below 30% capacity to prolong their life as much as possible. Having said this, it should be added that the daily consumption will be multiplied by the number of days of independence you want to ensure. This is because the mini solar panels work with sunlight, but when travelling with a camper, this is only sometimes available. This means that if, for example, you have obtained a daily consumption of 1000 Watts, these will be multiplied by the days of independence that you want to guarantee even when there is no sunlight. For example, 500 Watts x 4 days = 2000 Watts, which means a battery bank of about 500 Ampere at 12 Volts.
Second step: Choice of solar panels and charging system
As you will have understood, the central point of an audit is to determine how much energy it is necessary to create and, therefore, how many batteries it is essential to store. The same Audit is also required to determine what type of Inverter is needed to power your 220 Volt equipment. Solar panels vary in terms of quality and efficiency. Usually, this translates into a difference in price. Still, the general rule is that even though everything is read on the net talking about campers, it is always better to plan to use Monocrystalline panels since, compared to Polycrystalline have a higher surface yield and work better at low temperatures, which essential when using the camper in winter when there are fewer hours of sunshine.
Solar panels are usually listed by their capacity in Watts, but their efficiency varies, so you should check each panel’s specified charging capacity in amps.
Third step: Evaluate the spaces
Although listed as the third step, this step should be seen and analyzed as the first among the aspects, given that it would be useless to calculate that you need 1000 Watts per day when you have the space available for a much smaller panel surface. This means that you may understand that your installation does not guarantee your needs, so you will have to make choices in this case. But beware, because spaces aren’t just about portable solar panels for rv, it would be all too easy to think so. In reality, the regulator, the Inverter, the charger, and the batteries need their spaces and cannot be stowed in the first place that happens. To be clear, a 500 Ampere battery bank could even weigh 150 kg, and it is only sometimes possible to place it under the dinette table. Maintenance also needs to be considered, so everything needs to be easily accessible. The rooms where the electronic devices are installed must then be ventilated and away from the heating vents.
Fourth step: Install the panels
As for the rigid panels, these can be installed on the roof using special support brackets glued with the classic Sikaflex 221 or 252. The important thing is that the panels can be removed without difficulty, leaving the possibility of doing maintenance to both the panels themselves and the camper’s roof. The electric cables must be passed so they avoid getting stuck with branches, and the water can flow underneath without creating stagnation areas. The panels must be mounted suspended with at least two centimetres of air under their base so that the heat produced comes out of the sides. If you create series/parallel strings, we advise you to carry out all the wiring on the roof to enter the camper cell with the least possible number of cables. Naturally, the passage must be sealed. In this case, we used boxes for outdoor civil and electrical systems. Having the possibility to do so, the panels can be mounted with a minimum inclination towards the front of the vehicle. This allows for better natural washing and less water stagnation. It is essential that the panels can be detached from the roof without cutting the cables. For this, you will need to use the appropriate connectors. In addition, of course, it will be necessary to use a line suitable for solar systems, which are specially designed to resist high temperatures and UV rays. This must then have an adequate section concerning the system you are installing. However, never use ordinary electric cables.
Fourth step: Install the solar system
This should be the shortest and simplest step if you have planned everything well, especially if you have chosen a modular system such as the Renogy Energy products we have mentioned. You don’t have to be a qualified electrician to do this, but you need a basic understanding of electrical systems and some essential tools. The thing to pay particular attention to is the section of the electric cables to be used and the type of connectors to make the connections to the batteries. The Renogy devices that we have used contain well-done instructions and, for example, explain the assembly methods very well. It is easier to make mistakes if you want to do your own thing and, sooner or later, find yourself immersed in problems. If you have neither of these skills or if you can’t do either, it makes sense to think about getting professional help to avoid doing damage or, worse, getting hurt.
