Magazine, Tools & Home Improvement

Ultimate Guide to Portable Solar Panels for RV

Portable solar system, which can be a foldable solar module or solar case. Not only for motorhomes, but mobile solar modules are also of great advantage. Whether camping, caravanning, or allotments – stellar examples are a portable solution if you want to generate electricity very quickly.

But what about a solar case, how does it work and where are the differences to a standard solar system? What is the difference between solar cases and foldable solar modules and what do you have to be aware of when operating? Where can you buy a solar case, how much power does such a mobile solar system have?

In this article, you will learn how to use unusual solar cases as a mobile solar system, why a foldable solar module is even better, and what you have to pay attention to when buying and operating.

Solar case (folding module), what should I imagine?

The basic idea was to install solar modules perpendicular to the sun to achieve a higher charge current when the sun was low. In the meantime, however, there were more and more applications for mobile solar systems. “Mobile” in the sense that a solar module is not mounted stationary, but can be portable, mobile in different places. The latest generation of solar cases is made of impact-resistant, lightweight GRP. These mobile solar systems are thus particularly resistant to shocks. Foldable solar modules enclosed by a fabric bag, which can be folded together to save space. So you get a high performance despite low packing dimensions and little weight of only 5 kilos. Incidentally, the name “solar case” comes from the fact that mobile solar systems in the first series were still made of conventional glass modules, which are simply

The solar system at the motorhome, worth a purchase?

Time and again, I am asked if solar is worth it at the motorhome. How much electricity can solar modules deliver? 
This question is easy to answer. Solar systems are a one-time investment that is not that expensive anymore. Once purchased, they then deliver free solar energy to the batteries for many years. Depending on the size of a solar system, the stand-alone life can be extended or even extended to almost infinity. For every need and budget, a suitable solar system for your motorhome can be put together.

What is so special about a mobile solar system?

Solar modules generate electricity from sunlight. Solar modules work most effectively when the sun is just above the blade. Every angle deviation lowers the module current. If solar modules are mounted flat on the roof, there will be a power curve throughout the day. Low power in the morning, much at midday and again little solar charging in the evening. This effect also occurs throughout the year. In winter, it is profound – in summer high. On winter noon, for example, the charging current is significantly lower than in summer.

The solar case has an unbeatable advantage that it can be precisely aligned with the sun’s rays. That’s why you can even at the end of December a similar charging power as in the summer. Small deductions must be accepted, however, because the winter sun has a long way through the atmosphere, which is why you lose some of your strength until it reaches the solar case.
However, you could easily set up solar panels on a camper or caravan with a device. Such sun-oriented solar modules have the disadvantage that they must be brought back into a “driving position” before each trip. Climbing on a motorhome may not be for everyone. Depending on the tilt direction of the solar modules, the vehicle must also be oriented to the south, which is not always possible, depending on the parking space. With the solar case, you now have the advantage of being able to align the foldable solar module exactly to the sun regardless of the vehicle. So you get a, almost constant throughout the day, high solar power.

Mobile solar system

“Mobile Solar System” is a portable solar system for charging batteries. The components can be used flexibly and can be stowed in a space-saving way.

A portable solar system usually consists of a solar module, solar line, a solar charge controller and a Best AGM Battery connection cable.

With mobile solar chargers, however, no charge controller is needed because these individual solar modules are equipped with a USB plugin that the smartphone/tablet can be plugged in directly. Charge control, in this case, takes over the mobile phone itself.

Solar cases and folding modules are only set up when power is needed to charge a battery. The solar module is placed in the sun and connected to the battery.

  • Nothing has to be permanently installed.
  • In the motorhome, no holes are drilled in the roof.
  • In the allotment garden, nothing can be stolen, because you take your mobile solar system when not in use only with the home.
  • Flexible use for camping, caravan, boat, car and camping

So that their mobile solar system cannot be stolen, some campers can come up with wild constructions, but it can be so easy: You re-pack your foldable solar module after use, it can not be stolen anymore. But theft protection is not the main argument for a mobile solar system. Their versatility characterizes solar cases, such as folding modules.

On the one hand, they can be deployed as portable solar panels anywhere and generate power to charge a 12V battery. On the other side, they can be stowed thanks to their folding mechanism extremely space-saving.

With stand-on feet, a mobile solar panel can be aligned precisely with the sun and tracked throughout the day. This makes a 100W folding module as effective as a 200Wp solar module mounted flat on the roof. Especially in spring, autumn and winter, this is of immense advantage if you can align a mobile solar system of the sun.

Possible uses for solar case / foldable solar module

There are no limits to the ideas. Mobile solar modules can be used wherever the sun shines and a 12V battery is to be charged. Practical is also the possibility that your vehicle can park in the shade and the solar case, standing in the sun, can still generate electricity.

Solar system T5 California (VW T6 California)

Camping buses such as the VW T6 California with lifting roof are confusing to equip with a solar system – it merely lacks the required roof area. To be able to stand autonomously with the VW bus a few days longer and without power supply in a sweet spot, mobile solar systems offer themselves. Put your Faltmodul next to the car or put forward behind the windshield; already, your body battery is recharged.

The foldable solar module 100Wp from SolarSwiss has proven itself, especially for the VW BUS with lifting roof. At just 5 pounds, it’s not only the lightest portable solar panel; its low pack size is ideal for touring the T6 California. The foldable solar module can either be placed inside the windshield or even better, be placed outside directly in the sun. Thanks to a longer solar cable, the VW bus can be parked in the shade while your solar module creates electricity when placed in the sun. The energy yield of a 100Wp portable solar module is enough to recharge the supply battery of the VW California 100% on a sunny day.

Mobile solar system for the motorhome

Solar cases (100W) are often used in motorhomes; they complement the solar system on the roof in the low sun from autumn to spring ideal. Many overwinterers who spend the cold season in the sunny south, put a mobile solar panel directly into the sun, thereby receiving more charging current for their onboard battery. Prevalent here are solar cases, consisting of two solar modules, which are connected with hinges. The blades can be folded when not in use and stowed, so save space in the camper.

But also foldable solar modules, integrated into cloth bags, enjoy ever-increasing popularity. Because these folding modules are particularly light, small, and still very productive, thanks to the high-performance solar cells used.

Camping solar system

Free solar systems are ideal for all types of camping activities. Wherever there is no electricity, the mobile solar system is used. It is only set up when you need power. Otherwise, it is stolen safely in the camper or caravan.

Even at the campsite, you can save yourself the power savings by self-generated solar power.

Foldable solar module or solar case?

Solar case vs. foldable solar module – both have their advantages and disadvantages. First of all, the fundamental differences between portable solar solutions:

Solar examples consist of two solar modules with 50Wp each. These are hinged and can be folded. The solar modules have an aluminum frame and the surface is made of glass. That makes solar case heavy. The hinges create a hinged solar module, which has the same performance as a 100Wp solar module, but when folded, only half the size. So the solar case can be stowed away space-saving in the motorhome or caravan. At 12 kilos, solar cases are not particularly light, and their glass surface is slightly sensitive when the solar case should fall, for example, by wind, with the glass side down.

On the back of the solar pot are two support feet, which are issued after the modules have been opened. As a result, the solar case can be aligned and tracked at any angle of the sun. Foldable solar modules consist of 3 smaller solar modules. They are folded twice, saving more space than classic solar cases. The cells of a foldable solar module are made of GRP and a plastic film, which ensures particularly low weight and insensitivity to shocks. Just 5 kilos weighs a Falt-solar module, which will be particularly enjoyable for some campers of the 3.5-tonne motorhome class. The packaging is already included because the foldable solar module is incorporated in a fabric bag, which protects the transport module.

If the sun is low, and there is no possibility to hang, an extra linkage can be threaded into the foldable solar module. This allows the portable solar module to align with the sun as desired.

Comparison of the mobile solar systemsolar suitcaseSolar folding module
mass12 kg5 kg
Dimensions closed54x70x7 cm55x46x4 cm
Dimensions unfolded70x109x3.5 cm55x167x1 cm
Performance in Wp100100
  • Is better in the wind because of the weight
  • Cheaper in the purchase
  • Extremely small and light
  • Packed in cloth
  • Can be used behind the windshield
  • Heavy
  • Glass can jump
  • Fails easier with wind
  • More expensive to buy

Technical aspects of the mobile solar system

A mobile solar system works exactly like a fixed solar system on the motorhome. With the difference that the modules are now portable, non-stationary, so not glued or screwed. The connection between the solar module and controller is a flexible solar cable used. As reasonable length has proved 6 meters.

A first mobile solar panel has the regulator externally at the end of the cable. The controller is therefore mounted directly to the battery and connected there. Either with ring cable lugs or only removable with crocodile clips (battery terminals). If you always want to operate the solar case in the same vehicle, then it is recommended to connect the solar charge controller firmly to the battery. The solar line remains securely attached to the solar controller and is only connected to the solar case or folding module if required.

How much electricity does a mobile solar system with 100Wp generate?

My measurements have shown that my solar case with 100Wp power can deliver over 50Ah (675Wh) of energy on a sunny day. Even in the winter in Spain, this value can still be achieved. In comparison, a solar system on the motorhome delivered flat-mounted, just 18Ah (243Wh) in winter in southern Spain. In the USA, you can even neglect the yield, lying flat on the roof solar modules provide a more homeopathic solar return.

Comparison: Solar case to classic motorhome

Possible daily incomeSolar case / Foldable solar module 100Wp100Wp solar system motorhome
Summer Germany650Wh480Wh
Winter Germany500Wh70Wh
Winter southern Spain650Wh240Wh

The table clearly shows how much more powerful a mobile solar system can bring than flat-mounted solar cells. Even in summer, foldable solar modules pay off

FAQ – Frequently Asked Questions:

  • Which battery types can a foldable solar module charge? 
    Common solar cases are designed to charge 12V lead and lithium batteries. It is possible to charge a car battery, a caravan supply battery, or any 12V lead-acid battery.
  • In the motorhome two onboard batteries are installed, is that also possible? 
    Yes, even several onboard batteries can be charged with the solar charge controller, the charging current is split between both cells.
  • I want more solar power, can you increase the power? 
    This is not a problem; some use two mobile solar modules to be completely self-sufficient.
  • Why not put the solar controller on the cigarette lighter? 
    Usually, the wiring from the cigarette lighter to the battery is not strong enough to be able to transport the solar charging current lossless to the battery can. Also, cigarette lighter itself is a significant weak point. Often there are contact problems here. Therefore, I strongly recommend to always mount the controller of the solar case directly to the battery.
  • Portable solar system to laptop load – is that possible? 
    Join! Portable solar systems also require a backup battery (car battery). But it can be used and charged during solar charging the car battery, your laptop.

Solar Set – foldable solar module Buy recommendation

A foldable solar module as a complete photovoltaic system (solar set) with high-quality components is available in the Amazon shop. The cosmic game is equipped with all necessary parts for operation. From the battery connection via MPPT solar charge controller incl. The super-light, foldable solar module by SolarSwiss from Germany, everything is included.

Solar cases from Amazon are cheaper to get, but here you have to lend a hand. The charging line is usually too short, must first be extended. The solar charge controller is an elementary shunt regulator, which will probably blur relatively quickly because of the high-temperature load because it is mounted directly on the module instead of at the end of the cable.

In summary: advantages/disadvantages of the solar case (foldable solar module):

Minimal installation effortOnly supplies power when connected
No holes in the roofCan be stolen
High solar yields through trackingOnly for 12V battery systems
The camper can park in the shade while the solar case is in the sun
Flexible use for the camper, caravan, boat, camping holiday.
Tiny packing dimensions with high solar power of 100-120Wp
Especially in winter, up to 7 times more power than flat-mounted solar modules.

Easy to retrofit solar case?

Solar cases can be retrofitted to any vehicle that has its power supply through a 12-volt battery. If you have not yet installed a solar system in your motorhome, you still need a solar charge controller for a solar case. The solar controller is firmly connected to the battery. Your foldable solar module will then only be connected to the controller if it is to generate electricity outside.

If a solar system is already mounted on the motorhome, there are two possible ways to retrofit an additional mobile solar system.

  • We build a second system with a separate solar controller for the solar case, which works independently of the already installed solar system (see above = without solar system). Nevertheless, your battery will not be overcharged because every solar charge controller separately monitors the state of charge of the RV battery. Overcharging of batteries is thus reliably prevented.
  • If a solar controller installed in the vehicle has sufficient reserves, module voltage from the roof system is equal to the Falt solar module; then, the solar case can be connected directly parallel to it. 
    Alternatively, a more significant charge controller can be installed, which can process the overall performance of both systems. Ideally, the solar system can be upgraded with a more efficient  MPPT charge controller.

As you can see, this way can be more complicated if you do not feel safe here, feel free to contact me in advance; I would like to advise you personally.

Can I load my laptop directly with a solar case?

No, whether a mobile solar case or a fixed mobile home solar system – solar systems always have the same structure. Solar module – regulator – onboard battery. Solar modules have a higher voltage than the RV battery voltage. Solar cases require a solar charge controller, which monitors the battery voltage and ensures that the battery is full but not overcharged. On the camper battery, the laptop, smartphone, tablet and other devices can be operated and charged.

There are small USB Foldable Solar Modules; these can charge your smartphone. But the performance is deficient.

How does solar power get into your battery?

A connection is effortless. Your solar controller will be mounted on your onboard battery. On the solar controller, the solar line is firmly connected, which is stowed when not in use in the vehicle. Now, if you want to use your foldable solar module, you join the solar line with your solar case and put it in the direct sun – already, the current can flow to the battery.

Do CIS solar modules provide power even in the shade?

I would also like to comment on this briefly, as I am often referred to. CIS cells have low efficiency. Otherwise, they would not be so big. In plain language, it takes more space to achieve the same performance as monocrystalline solar cells. 
CIS cells are significantly more expensive than monocrystalline solar cells. The manufacturers say that the CIS cells bring higher yields in diffused light – this statement is correct, as long as one compares a CIS module only with EQUALLY STRONG monocrystalline solar modules. However, if you compare CIS cells with monocrystalline solar modules of the same size, you will notice the difference. An 80Wp CIS module is 4cm more full and 4.5kg more substantial than a 100Wp monocrystalline solar panel. The 100Wp monocrystalline module has 20% more power than the 80Wp CIS – which roughly corresponds to the performance advantage of the CIS cell in diffuse light. Since our campers have limited roof areas, it makes little sense to spend a lot of money on large, low-performance solar modules.

CIS solar modules are less advantageous in the mobile sector

  • more width
  • more weight
  • less power in full sun
  • same performance in diffused light
  • twice the price of monocrystalline solar modules made in Germany.


Solar cases, like their successor, foldable solar modules, are highly recommended if a lot of power is to be generated with little energy. Since the mobile solar system can be directly aligned with the sun and tracked, the solar yield is much higher than with a flat-lying solar module of the same power.

I always say that if you already spend money on additional solar power, you should use it as well. An MPPT solar charge controller gets 20-30% more power from the solar panel – do you want to give it away? So pay attention to functional components and you will enjoy the foldable solar module for a long time.

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