The size of the solar power plant we install should be based directly on our annual electricity consumption. It makes no sense to buy too large a photovoltaic installation because at the moment it is not possible to sell electricity to the energy company. Currently, we can balance energy, so we cancalculatethe excess we send to the power company and recover 80% of it when we need it or use what we produce directly for our own needs. It should be borne in mind that one kWp of a photovoltaic module will produce about 1000 kWh of power annually. If our annual consumption is about 2000 kWh, we should design a power plant with a capacity of about 2000 kWp. However, if our consumption is as much as 10,000 kWh per year, we should consider a 10 kWp power plant. (kWp is the power of the PV module expressed in watts.)

When buying solar panels it is important to purchase a name brand from a known source, and not one of thecheap Chinese productions. The solar panel used in the installation of a solar power plant should have a linear power warranty which guarantees high efficiency for a full 25 years of use. It is also important to make sure that the solar panels are certified for ammoniatoprevent pitting in the solar cells and costly replacement after a few years.

Selection of grid inverter

The grid inverter, otherwise known as the inverter, is responsible for changing the direct voltage generated by solar panels into the alternating voltage of 230V or 400V that we have in the power grid. It is the heart of the photovoltaic system, and we must ensure that it is of high quality. The companies we recommend are Fronius SMA and Steca. They are the leading manufacturers of photovoltaic inverters that guaranteea high efficiency of over 98% and a long service life of over 25 years of operation. Please note that the cheaper Chinese substitutes produce significantly less solar energy (up to 20% less) than the high-performance brand name devices. 

Installation site of the solar power plant.

The best place to install solar panels is on the south side of the roof, angled between 25 and 50 degrees. Care should be taken that solar panels are not installed in an east-west direction or, even worse,towards the north. They should face the south with a slighttiltto the east or west of preferably no more than 15 to 20 degrees.

An alternative is to install the solar panels on the ground on adedicated structure integrated with the ground, by driving piles for example,or to place it on another type of structure not integrated with the ground. This option is much better because it does not require a building permit.

Solar power plant overvoltage protection.

Without exception, every solar power plant should have overvoltage protection both on the DC side (i.e., on the side of the solar panels that generate DC voltage) and on the AC side (i.e., on the side of the electricity supplier–230V or 400V alternating voltage). This type of AC/DC overvoltage protection will protect us against lightning during a storm and against overvoltage coming from the power grid. In the worst case, we wouldonly lose a fuse worth PLN 100 or PLN 200, depending on the model, and not an inverter that can cost up to several thousand or more PLN. Even if the installer/solar power plant contractor does not see the need for such security measures, we should strongly insist that they be installed.

How to choose a renewable energy installer

When choosing a solar power installer, you should look for a professional contractor who has been in the market for many years. It is not a good idea to choose a company founded only recently in response to the growing wave of popularity for solar power plants, because the installer’slack of experience can lead to serious errors in the design of the photovoltaic installation itself. It is also not a good idea toaccept the installation offers of energy companies and large sellers (e.g., furniture or other large stores) because theinstallerwill almost always be a subcontractor and if we need to report problems with the installation we will be forced to contact the energy company or the store, and not be able to deal directly with the contractor who installed the solar power plant.

“My Electricity”Photovoltaic co-financing

Currently, our country is running a nationwide solar power plant financing program called My Electricity. This means that after presenting the invoice for the purchase of a solar power plant connected to the grid, we can geta state reimbursement of PLN 5,000 for each photovoltaic installation. The application for co-financing must be submitted to the National Fund for Environmental Protection and Water Management along with the purchase document and a signed contract with the energy company for energy balancing.

What to Avoid When Installing a Solar Power Plant.

Choosing a photovoltaic installation–a solar power plant–is a decisionyou will live with for many years. Each solar power plant should be planned for a minimum of 25 years of continuous operation. The worst possible choice is thepower plant with the lowest price. Budget Chinese photovoltaic installations are characterized by low efficiency and a very high failure rate. If we want our power plant to operate for a long time and without failure, as well as to work efficiently without major problems, we should choose proven brand-name products.

Our company does not offer solar power plant assembly services. We only sellthe necessary components.

Artykuł Building our own Solar Power Plant pochodzi z serwisu SunTrack.

Unfortunately, a hotel gel battery can discharge in the first days of the stay and will need to be topped up. Of course, this can be done with an alternator while the vehicle’s motor is running, but it is expensive, noisy and cumbersome. A much better solution is to install solar panels on the roof of the motorhome. A properly selected photovoltaic system for a motorhome or caravan will ensure that we will not have to worry about energy shortages, and we will be able to enjoy our holidays with peace of mind. Below are the most frequently asked questions about solar systems for use in motorhomes and caravans, along with short answers to.

Should I choose a rigid or flexible solar panel for a motorhome?

In 99% of cases you should use a flexible solar panel glued to the roof. This solution is aesthetically attractive and resistant to theft and, above all, eliminates the problem of panels whistling on the roof while driving. Flexible panels also often take up less space. In addition, they do not contain water, as is the case with traditional glass solar panels, which can lead to delamination of the modules.

If we have a large motorhome with a flat roof and flexible panels, we do not have to worry about walking on the panels. If their entire surface is glued to the roof, they are strong enough to stand on. It is also worth mentioning that this kind of structure is more resistant to hail than a traditional glass panel.

Another factor is the price. Yes, rigid panels are cheaper, but when we consider the cost of assembly, the difference in price compared to flexible panels is less. The installation is also much more durable. The entire surface of the flexible panel is attached to the roof, while the rigid panel is only in connected at 4 or 6 points, depending on the kind of assembly system.

Is it possible to charge the battery with a solar panel and an alternator at the same time?

Yes of course. There is no fear that the alternator will interfere with the operation of the charge regulator or damage it. The regulators are fully autonomous and work with the battery based on voltage. The voltage level determines how the regulator will behave.

Do you need to disconnect the solar panels when a motorhome is connected to 230V?

No. When connecting to an external power supply system, you should have a 3-position switch in the motorhome that allows you to choose the type of power supply: solar panels, grid or zero. If the system is set to draw power from the grid, it has no physical contact with the solar system. The only contact that can occur is when charging the hotel battery from the network with a charger.But, as with the alternator, it has no effect on the solar system and there is no need to disconnect it. In general, the photovoltaic system should always be connected to the battery, if possible.

Where should we place the charging regulator in the motorhome?

It is best to place the charging regulator not more than 1 to 1.5 meters away from the battery due to large energy losses. The voltage drops much faster, due to the distance between the regulator and the battery, than it does between the solar panel and the regulator. It is simply lower and therefore prone to greater drops.

It is also important to provide an airy space for efficient gravity cooling of the charging regulator. It should definitely not be in a closed space.

Is a liquid electrolyte battery suitable for a motorhome

In general, liquid electrolyte batteries are not intended for cyclic operation, i.e., charging and discharging. This type of battery loses significant capacity after 20 full charging and discharging cycles. It should also be noted that these batteries are not sealed and may emit acid fumes harmful to health and should not be stored in the cabin. If we decide to use such a battery, it should be outside of the living spaces

Can we charge two batteries with one panel?

Yes.  DUO regulators are used tocharge two different batteries at the same time. Most often the two are a gel hotel battery and a liquid electrolytebattery in the engine compartment. Since it is possible to change the configuration, we can determine which battery will have the higher charging priority in 10% steps. Nevertheless, it is better to focus only on charging the hotel battery and, for example, to invest in a regulator with an MPPT system. This is especially true if the battery in the engine compartment does not supply anything except the starter.

Can we put a voltage converter in a motorhome?

Some motorhomes have them and they can be used as much as possible. However, it should be remembered that the voltage converter is an additional expense and when converting voltage from direct current to alternating current you lose about 10%. When equipping our motorhome or caravan, it is better to think in advance and purchase all 12V accessories. Currently, stores offer any kind of device we could want capable of being powered by 12V or 24V DC voltage. One big advantage is the silence. Without a converter, we do not have the noise of whirring fans in the cabin to cool the components.

Which panel should we choose for a motorhome with a refrigerator?

It all depends on what fridge we have. If it is an absorption refrigerator or a Peltier refrigerator with a fan, it does not make sense to choose a photovoltaic system. These types of refrigerators work non-stop and consume a lot of energy. They are intended to be used while the alternator is in operation. However, if we have a typical tourist refrigerator (12V/230V/gas) or any other type of compressor refrigerator powered by DC voltage, a set with a 100W panel and an MPPT regulator should be enough. However, if you do not want to buy a more expensive regulator, you can choose a 160W panel and a traditional PWM regulator.

However, if we have slightly more financial resources, it is worth considering the purchase of a 160W module with an MPPT regulator. This configuration will provide the entire motorhome with electricity in the months of April through September without the need to connect to an external power supply or recharge the battery from a rectifier or alternator.

Artykuł Solar panels in a Motorhome – FAQ pochodzi z serwisu SunTrack.

Unfortunately, not every solar panel can be connected to every regulator and careful attention should be paid to selecting them, even if the charge regulator appears to fit the solar panel.

Solar panels and basic parameters.

Watt – is a unit of power. It determines how much energy the panel can produce at any given time. An example would be when a 100W panel works for 1 hour at full power. It should generate 100Wh of electricity, which is equivalent to operating a 100W bulb for 1 hour. Of course, this is an estimate and no losses have been considered.

Voltage – is the power component, expressed in Watts. Voltage (V) * Current (A) = Watts. Low-voltage panels offer a voltage of up to 22V, while high-voltage panels up to 60V, but the most typical voltage is 36-40V. Each solar panel has 2 values. Voltage under load and open circuit voltage. In the case of a series connection, the voltage will increase and in parallel, it will remain the same.

Current – This is expressed in amperes and is a component of the power expressed in Watts. It is assumed that the lower the current and the higher the voltage, the smaller the losses. Therefore, it is a good idea to connect solar panels in series, and not in parallel, if possible. If we have high voltage from the panels, such as 70V or 100V, we can confidently run the cable up to 20 meters without major losses. However, if the voltage is below 20V, at such a distance we can lose up to half of the energy due to the resistance of the cables.

Selection of a solar panel for a PWM controller

The PWM charge controller has two very important parameters. The first is the maximum charging current expressed in amperes. The second is the maximum voltage of the solar panels. The most common values ​​are max 30V for a 12V battery and 50V for a 24V battery. When selecting a solar panel, the maximum values of voltage and current must not be exceeded. When connecting more than one photovoltaic module, it is recommended to connect in parallel so as to raise the current and not the voltage. It is also worth reading the manual because some manufacturers, such as Victron Energy, also limit the power of the regulator in Watts.

Selection of a solar panel for the MPPT controller

The main parameters of MPPT regulators are the maximum voltage of solar panels expressed in Volts and the maximum allowable total power of solar panels for a specific battery voltage. When connecting solar panels to the regulator with the MPPT system, we should pay attention not to exceed the maximum voltage recommended by the manufacturer when connecting the panels in series. It is best not to exceed 90% of the upper limit since, in winter,colder panels generate higher voltage. Also, the total power of the panels for a given gel battery voltage cannot be exceeded. An example is the Victron Energy 75V/10A charging regulator with a power limit of 145W. This means that the module cannot exceed a voltage of 75V ora power of more than145W.

Exceeding the voltage and current limits.

Exceeding the upper voltage in the charge regulator willactivate the protection feature which deactivates the regulator until the voltage is reduced. Unprotected cheaper units may be damaged. However, if we exceed the current or power of the panels by a small value, e.g. 10-20%, nothing bad should happen. In the worst case, the regulator will cut the excess power, but it will continue to work.

When the current or power limit is exceeded by more than 20%, the regulator will overheat and even melt. Sooner or later, exceeding the limitswill always permanently damage to the device.

Which regulator is better with the PWM or MPPT system

Without a doubt,the MPPT regulator is the better system. It allows us to charge at a level of 20-30% of the solar panel’s power on days without sun, or in shade, and even in rainy weather. Unfortunately, MPPT systems are sometimes up to twice as expensive as classic MPPT charge regulators. However, this does not mean that a PWM regulator is bad. It works as well as the MPPT regulator but only with full sun exposure. In partial or full shade, it provides only a small percent of the power of the photovoltaic module.

Artykuł How to choose a solar panel for a PWM & MPPT controller? pochodzi z serwisu SunTrack.

What does it mean that the regulator is an MPPT regulator?

MPPT is the maximum power point determined in the current-voltage characteristics. MPPT is the MPP tracking system of the PV generator. MPPT charge regulators have a built-in MPP electronic tracking system that constantly wanders around the solar panel looking for the maximum power point. Thanks to this, MPPT regulators make it possible to obtain approximately 30% more power from the panels thanwith PWM regulators. MPPT regulators work very well in the atmospheric conditions prevailing in our country. They allow you to charge the batteries faster on cloudy, rainy days with less sun. They work perfectly in the autumn and winter season, when there is much less sun, and the days are short.

MPPT regulators from Victron Energy.

The Dutch company Victron Energy offers a wide range of MPPT regulators, specializing in devices for photovoltaic installations. VE regulators have the highest European quality, satisfying even the most demanding customers. These regulators are made with the highest accuracy in a blue metal housing. They have signaling diodes that inform the user about the operation of his system. These controllers have three outputs: one for connecting panels, another for connecting batteries, and the third for connecting loads. The controller automatically adjusts itself to the system voltage. The innovative BlueSolar algorithm always maximizes energy consumption, allowing for effective battery charging even through a partially shaded panel. There may be two or more Maximum Power Points (MPP) on the power-voltage curve in the event of partial shading.

Thanks to the output that allows you to connect the load, the regulators guard the operation of gel batteries connected to the system. They do not allow them to be over- or under-charged. They disconnect the load as soon as the battery starts to discharge. In this way, the service life of the batteries is increased.

MPPT regulators and their cooperation with VE. Direct Bluetooth LE Dongle.

The latest design, that makes it easier for the user to use a solar system equipped with an MPPT charge controller,works with the VE.Direct Bluetooth LE Dongle. Thanks to this cooperation, anyone can observe the operation of his system on a mobile device. The VE.Direct Bluetooth LE Dongle works with both Android and Apple systems. When using the VE.Direct Bluetooth LE Dongle with the free downloadable Victron Energy application on your mobile device, you can easily connect to your MPPT controller via Bluetooth. In this way, you can easily check the state of charge and discharge of the battery and charging errors at any time. You can also change the settings of your installation. It is a very convenient solution for people whose installation is outside their permanent place of residence.

Artykuł Charge Regulators with the MPPT System pochodzi z serwisu SunTrack.