Knowledge Db

Overview of Installation and connection of solar panels

The installation of solar panels is one of the simplest “Do It Yourself” tasks and the results will give you total convenience.

In summary, there are 3 simple steps to installation:

  1. Connect a cable from the regulator (battery symbol) to the household battery.
  2. Glue/screw the solar panel in place.
  3. Run a cable that connects the solar panel +/- to the regulator +/- (solar panel symbol)

Sometimes stage three might be the only physically hard part, due to tight spaces that can be difficult to access. Planning ahead is a good idea.

When installed your system will without any interaction on your behalf let the sun flow into your Batteries.

Planning the purchase

What type of solar panel do I need?

SUNBEAMsystem manufactures high efficient, high quality solar panels for vehicles and boats.

On any type of vehicle, you would normally prefer a small, lightweight and thin solar panel that produces a lot of energy.

Our big range of models will ensure that you can choose a panel that will suit your needs. Generally, our panels produce more energy per available space than others which is important when you only have small areas available.

With our range of Flush models, you avoid the need to have a JunctionBox. With these models you have an absolutely flat surface without any protruding parts. If you can run the cable through the surface, then the installation will be virtually connectionless. If you need to run the cable some distance, you might glue the cable along the surface and it will be almost invisible.

Our Tough model range offers an outstanding longevity compared to other lightweight solar panels.

The combination of Tough and Flush is the most popular version of panels.

Find a suitable place for the panels

No matter if it is your first solar panel or if you need more, the available space is of essence. If you have a boat we would like to remind you that you can walk on our panels, this might open up some extra available space. If you have a RV with a full roof, you could consider the sides. We do also offer special models for canvas to be used on a boat or for example a tent used together with a RV.

You could benefit from using several smaller panels to fill up available spaces. One panel on each side of an obstruction is often much better compared to one panel. If you often experience shadows covering the area meant for solar panels you might benefit from choosing two panels instead of one. Two panels can be connected to the same regulator.

For odd surfaces with a big difference in solar angle and shadowing one could benefit from using one regulator per group of panels for the different surfaces (when using MPPT regulators).

Our 100W panels are designed to be permanently glued or screwed to a firm surface. If you plan for any type of semi- permanent or temporary usage then the maximum recommended size is 50W

Does the angle matter?

No matter what brand of solar panels you choose simple physics will lower the production when the panel is not angled towards the sun. If you live in the northern hemisphere you might for example find yourself in the situation where the sun is 45 degrees over the horizon in the south.

IF you then instantly compare a solar panel lying flat on the ground with a solar panel directed towards the sun you will notice more than 30 % drop in production.

This will trigger even the least competitive person. But please stay calm, we would like to share some further knowledge. IF you would measure on the two panels mentioned above over an entire day you would only get a 11% drop in the total production for the panel lying flat on the ground compared with the panel angled 45 degrees towards south.  This is because of the sun’s movement over the day.

This is GREAT NEWS for all of us planning to put solar panels on moving boats and vehicles. One can safely attach solar panels on top of the vehicle or boat. The most practical and safe solution but still one that is almost as good energy wise as any of the more inconvenient mounting solutions.

Of course, the most efficient solution would be a solar tracking system, this is often found at solar power plants. A tracking system is usually expensive. If you plan to fit the solar panel on a pole and manually adjust it, please consider that this would mean that you have to set the alarm and every hour from dusk to dawn adjust the panel manually. This if you want to get the benefits from tracking the sun. If you find this complicated you will then have to choose between leaving it horizontally or slightly angled towards the south (as long as the boat is not moving). The Pole has then mostly lost its purpose except for possibly be kept away from some shadows.

At SUNBEAMsystem we truly believe that solar panels should be something you install and then forget. The best solution for your energy problems but also the least troubles. Hence we only build lightweight panels built to be fitted on a firm surface.  Our panels are not built to be fitted on a pole but we do offer the QuickFix model and the Sunzip upgrade for the same. This will allow you to fit solar panels on top of any type of Canvas like a tent, bimini or sprayhood/dodger. The fittings are semi-permanent and will only come loose when you want to.

How much will a solar panel produce in bad weather?

This is hard to give a precise answer but generally on can say that as long as you can feel the suns heat on your skin through the clouds you will get energy from your solar panels. If the clouds are grey/blue and you do not feel any heat the energy produced will be minimal.

SUNBEAMsystem solar panels have won multiple tests in comparison of production in non-laboratory weather conditions.

Will the solar panel interfere with my other charging equipment?

The regulator takes care everything automatically and you can keep the old mains charger and generator/alternator. They will not interfere in a bad manner and you can enjoy a carefree charge of your batteries.

A simple method to calculate solar panel sizing

The physical space available as well as the energy consumption measured over 24h are the two most important factors when choosing the size or amount of panels needed.

The simplest kind of sizing is to try and even out the single biggest electricity consumer. This is very often the fridge. By using this method you would in general need some 60W solar panel (or panels). But it could of course vary between 30-100W depending on the type of fridge, age, insulation and climate.

The Fridge is usually one of the biggest consumers on a yacht or RV. If you have other energy consumers and would like to be totally independent of other means of charging you would of course need even more solar panels.   But bear in mind that any solar panel will help a lot and prolong the times needed between charges.

If you need the most energy out of a small available space you should choose a SUNBEAMsystem solar panel.

Does the size of the batteries matter?

The size of a battery is measured in Ah (Ampere hours). To know how many Ah your battery bank can store you should add the Ah for each individual battery. You could look at it as the size of water tank.

When you empty or fill you tank you measure the A (Ampere) going in our out.

When choosing solar panels no special considerations needs to be taken in relation to the size of your battery bank.  The panels should rather be sized in relation to the amount of energy used over a 24 hour period. (You might read more regarding this further down).

The battery type might still matter and could affect the type of regulator, read further down regarding regulators.

Advanced: Solar panel sizing.

In general, we could say that most users will increase their energy consumption a little bit every year. It might be good to plan ahead for some extra solar panels in the future or go for extra solar panels or the bigger size right away.

To make an exact calculation of the need, you have to know your energy consumption over 24h. You could use measuring instruments or you could find the data on the products you use. Another way is to look at the size of your battery bank and how much you use. For example if you have a 100Ah bank and you know that you use 20% over 24h then you could assume your need is 20Ah per 24h.

To calculate the consumption from data you need to know consumption and the time. Example Fridge 1.9A and lights 0.3A.  Lights might be used for 3 hours and the fridge for 18 hours.  The total amount of used Ah, 1.9×18 + 0.3×3= 35.1 Ah

To calculate the amount of solar panels needed we would need to know how many sun hours we have in average. We could also enter a factor to take into account low solar angles during late and early hours. Up north in Sweden (the origin of SUNBEAMsystem) we would do 0.7x sun hours on mid day and something like 0.5 x sun hours early and late. On a sunny day we would then have 0.7×3 + 0.5×6 = 5.1 hours

We would then take 35.1 Ah and divide by 5.1 hours which equals 6.8 A

Then use 13volt to multiply with 6.8A and we get 88.4 Watt which corresponds to our minimum need of solar panels.  (ofcourse a 44Watt solar panels would double the time between needed recharges by other means)

Choose the regulator

Chose the type of regulator: Standard or MPPT

A simple regulator might be a cost-effective solution. A MPPT regulator may be more costly but will render more energy from any type of solar panel. Theoretical calculations might give up to 30-35% more than a simple regulator. In real life one should count on between 0-20% increases in production. The result depends on the conditions.

So how to choose? Let’s say you would get 10% more production out of your solar panel with an MPPT regulator. Then compare the cost for 10% bigger solar panels versus the more expensive MPPT regulator. IF you have a limited space we would suggest that choose a SUNBEAMsystem solar panel to get the most out of the available space. Then secondly you also consider if you need the 10% extra as well.

If you have unlimited space it might sometimes be cheaper to choose an inexpensive regulator and buy several panels or a single larger panel.

Find the regulator Size

The regulator will be stamped with a maximum number like 10A or 20A.  This is the highest current produced by the solar panel(s). It has nothing to do with the size of the battery bank.

10A equals about 130W in total of Solar Panels, 20A 260W and 40A 520W.

(for 24V battery system, double the watt).

Example : You purchase two 50W solar panels, that sums up to 100W. Since a 10A regulator will handle up to 130W solar panels this is the correct choice.

Type of batteries

Most regulators are suitable for Sealed Lead Acid batteries. If you have Gel or AGM type you need to make sure that your regulator could be set to charge this type of battery. The same goes for any type of mains charger. If you have Lithium batteries you need to take extra care in choosing the regulator because old type of lithium batteries needs special programs. On the other hand the latest types of advanced Lithium batteries will accept almost any type of charger.

Advanced: 24 Volt systems

In you got a 24V system all our regulators will sense this automatically.  –  The only difference is that two panels (of the same model) need to be connected in series (connect the panels plus to minus and use the “left over cables” to connect to the regulator )

Alternatively you could choose a Boost-regulator manufactured by Genasun. This will enable the use of a single solar panel on a 24V system.

Advanced: Performance

The competitive user might notice that a MPPT regulator most often performs better when not used with solar panel wattage close to the maximum rating. Hence an oversized regulator might produce a few percent more.


Connect the solar panel and regulator.

In moist environments like a yacht or RV one should always use pre-tinned cables for the best performance over time. These are recognized by the silver colored threads instead of the copper color.

First connect the regulator to the service battery like illustrated below. By doing this a regulator with autosensing will recognize the battery system.

Second connect the solar panel. In almost every case a long cable will have to be used and a connection between this cable and the solar panel cable needs to be made.

If you have a detachable solar panel you will most probably have MC4 waterproof connectors on this one and you should put compatible MC4 connectors on the end of the cable from the regulator. The metallic part in the MC4 connector needs to be soldered to the wire and then put inside the plastic part with an audible click. Then screw the cap on firmly to achieve total waterproofness. Please not that just squeezing instead of soldering might cause a defective connection and in worst case fire due to heat.

For Flush model panels that do not have any connectors you need to run the cable inside and here connect it by your favorite connection type. Please remember that how simple and convenient your usual connection is – soldering is superior to all other methods.

Choose thick (big cross area) cables to avoid losses. Use our calculator to find a suitable cable cross area.

A small percentage of losses are acceptable in the cable running from the solar panel to the regulator. Between the regulator and battery you would like the voltage drop to be zero. Hence it is important to place the regulator close to the batteries or main cables.

Note that in the diagram the “load” port is not used. This is an extra feature that can be used with a timer that is set in relation to sun rise and set.

Planning multiple solar panels

Parallel Connection

Any SUNBEAMsystem panels can be put in parallel with other SUNBEAMsystem panels without extra considerations. For the best result use models with similar Vmp (found on the back)

As wattage and distance to regulators increases the cross area of the main cables running from the solar panels to the regulators needs to be increasingly bigger to avoid losses in the cables.

Serial Connections

Please observe that to achieve the best performance we do recommend a connection in parallel according to above.

SUNBEAMsystem solar panels can be put in series. The recommendation is to use 2 to 3 panels in series but in extreme cases a maximum of 5 units can be used if installed by a professional. The maximum will always depend on the MPPT-regulator as well. By-pass diodes according to the picture is needed. On JBox models there is a by-pass diode built into the box but on Flush models this needs to be connected separately for each solar panel.

A serial connection might be needed for a 24V (or higher) system, if you have a 12V system consider choosing a parallel connection with sufficient cabling.

Before putting panels in series, please consider the pros and cons of this solution.


Higher voltage on the solar panel cable backbone.


  1. A Constant small power loss in the by-pass diode not normally experienced on the diode-less Flush models.
  2. The diodes will increase partial shading performance but serial connected panels will still produce less in most shading conditions compared to parallel connected panels. The result is most often less total performance over time.
  3. The solar panels well being is dependent on a single point of failure (a by pass diode). If this fails or is installed in a incorrect manner it might shorten the life expectancy of all of the solar panels in the connected series.

Serial Connections for Flush Models

To achieve a secure installation as well as the best performance in shading conditions a by-pass diode is needed for every single panel.

If needed one could choose to exclude the diodes. SUNBEAMsystem solar panels are safer than older types of panels and could be put in series without by-pass diodes if the total wattage is kept below 150W and the total number of SUNBEAMsystem panels is not higher than two. This setup will however underperform in any type of shading conditions and is not recommended if any type of shading might occur.

NOTE: Incorrect diodes can damage your panels. Our retailers will provide the right sized diodes needed for your isntallation upon request.

Solar panel arrays consisting of combinations of parallel and serial connections.

For large arrays a combination of Serial and parallel connections will have to be used to find the right combination of voltage and high amounts of panels.

  • The maximum number of panels in series is five
  • The number of parallel groups are limited by the regulator maximum.
  • The same pros and cons as earlier described regarding parallel vs. serial connections applies here as well.
  • Use a balanced symmetrical setup.
  • Main cables should have a sufficient cross area.
  • The Same size and model solar panel should be used.
  • One by-pass diode needs to be installed per each panel (JBox models already got this).
  • For each serial group one fuse should be present. The fuse rating should be according to Ioc printed on the backside of one of the panels multiplied with 1.25. (example, 6×1.25=7.5, then choose 8A fuses).

The Fuses replaces blocking diodes traditionally used. The choice of fuses will improve the production compared to using blocking diodes.

Below is an example of 2P2S (two in parallell with 2 in series)

JBox panels use MC4 connectors and has got the by-pass diode inside the box. This makes connection easy. Simply connect plus to minus on the panels in series and use MC4 connectors or MC4-T connectors for the backbone.

Flush panels (flat hidden cable) needs to have the cables run inside for connecting Diodes and connection to the cable backbone.  Remember that the cable can be glued along a white plastic surface with an almost invisible result.

The direction of the diodes is crucial so please take extra care when connecting. The direction of the printed band should be the same as the band in front of the arrow in the diode symbol. When only indicated with plus and minus it should be connected in reverse to the polarity of the solar panel. Study the pictures below carefully.

NOTE: Incorrect diodes can damage your panels. Our retailers will provide the right sized diodes needed for your isntallation upon request.

Multiple arrays

If a high expected consumption has to be met with a large solar panel array then one should follow some simple advice. On an environment with different main directions or reoccurring shading conditions (like a yacht) one could benefit from having several arrays with one MPPT regulator each. For example, one starboard and one port array

Follow this link to find further examples when installing on a 50-60V battery system

This might also be the only solution when many panels are needed but the regulator max rating would have limited the number of panels.

Choose the same brands and models for the regulators. One regulator per array.

The same rules and recommendations mentioned above for single arrays applies here.