Hybrid Inverter Charger

More on hybrid solar inverters

Grid-connected hybrid inverters are perhaps becoming more and more common in the industry, but this does not mean that they are the most suitable option for individual users.  Grid-connected hybrid solar inverters are gaining market share as the option of self-consumption with batteries is gaining popularity, as they allow the user to continue with service thanks to their installation in the event of a grid supply failure.

This type of inverter is capable of operating connected to the grid, being able to manage the system's battery charge and, on an ad hoc basis, to operate the system without grid supply exclusively with the use of the energy stored in the batteries or with the energy being generated at that moment thanks to the photovoltaic solar panels.

These inverters are the most versatile and flexible inverters available in the industry. They allow for optimal management of the different energy sources available (solar panels, batteries and the grid). They are optimal for hybrid systems with several consumption loads and varying generation sources, thus allowing an intelligent management of the system (grid / consumption / solar generation and batteries).

The operating voltage of this type of inverter is usually between 48V and 500V depending on the different components used. This type of inverter can operate in different modes depending on each situation:

- Charge mode: when there is no generation from the solar panels and the batteries are completely discharged, the solar inverter will charge the solar batteries from the grid. The charging mode also occurs when the consumption of the loads is lower than the solar production. In this way, the surplus that is not consumed is stored in the batteries for later consumption. The charging mode is the great advantage of hybrid inverters as it allows peak-shaving. In other words, energy can be stored during production peaks and when consumption is lower (especially in the case of domestic consumption) so that this energy can be used later (via the solar batteries) at night or in the afternoon when there is not so much solar generation and consumption tends to rise compared to the middle of the day.  Hybrid inverters also allow programming when the charging mode is executed and which is the source that charges the batteries. Sometimes, given the price of electricity, it may make sense to charge the batteries with grid power or sometimes to prioritise charging with solar panels. Properly programmed charging mode allows us to optimise charge/discharge/generation and consumption flows as appropriate in each situation.

- Off-grid mode: The system operates as if the grid did not exist. The loads are fed by the solar panels and the energy stored in the batteries. This is undoubtedly another major advantage of hybrid solar inverters. Something that might seem like a no-brainer is not so clear-cut. Not all grid-tied solar inverters can operate when the grid goes down. In fact, as we have explained in the section on grid-tied solar inverters, they usually cannot operate without the grid as they are not able to synchronise with the necessary parameters to be able to operate. That is why when an inverter does not have an off-grid mode it cannot supply electricity to the loads if there is no grid, even if there is sufficient solar generation. It is possible that in some cases, even if the inverter has an off-grid mode, it is necessary for the solar batteries to be able to operate in off-grid mode. Sometimes battery manufacturers supply what they call a "back up" module to be able to work in off-grid mode. 

-Self-consumption mode: The solar panels supply electricity to the loads instantaneously and any surplus is stored in the batteries if they still have capacity. Otherwise the energy is fed into the grid. Self-consumption mode would be the mode that a grid-connected inverter could have. The panels generate and at the same time the inverter feeds the loads instantaneously. 

Hybrid inverters "off-grid" or for off-grid installation

Inverters that are installed in off-grid installations that allow the batteries to be charged, for example, from an auxiliary generator or the grid, are sometimes also called hybrid inverters. These are, for example, 12V hybrid inverters or 24V hybrid inverters, which can also be referred to as stand-alone hybrid inverters. In this case, the fundamental difference is that the latter are not able to synchronise with the grid and do not feed their energy into the grid, so they always operate in parallel. This type of inverter integrates the battery regulator/charger in its electronics. It is very common for an isolated system with batteries to be made up of the inverter + regulator/charger + solar batteries. Hybrid stand-alone inverters integrate the inverter, regulator and charger in the same device, making these inverters more compact and easier to configure. 

What is the difference between a hybrid inverter and a normal inverter?

The main difference between a hybrid and a normal solar inverter lies in the additional capabilities in terms of energy flow management offered by the hybrid inverter. Here are the main differences:

- Dual functionality: A solar inverter either grid-tied or "off-grid" converts direct current (DC) to alternating current (AC) to power electrical devices instantaneously, i.e. the electrical energy must be consumed at the same time of generation. On the other hand, a hybrid inverter not only performs the function of an inverter, but can also act as a charger for solar batteries. This means that it can charge the batteries connected to the system using energy from the grid or from renewable sources such as solar panels or wind turbines or non-renewable sources such as a diesel generator.

- Energy storage: Hybrid inverters are designed to work with energy storage systems, such as batteries. They can manage the charging and discharging of batteries efficiently, allowing excess energy generated during times of high production to be stored and used when production is low or in the event of power outages. Hybrid inverters are responsible for controlling the charge/discharge parameters of the batteries according to the consumption needs and according to the values allowed by the batteries. Hybrid inverters normally communicate with the BMS (Battery Management System) of the batteries to carry out these controls and management. This communication occurs mainly with the most modern batteries (with lithium as the main technology) via a CAN or RS-485 communication port. This is not the case for lead-acid or stationary batteries without the mentioned BMS.

- Autonomy: Due to their ability to charge batteries, hybrid inverters allow systems to operate autonomously, even when grid power is not available or during power outages. Normal inverters rely solely on grid power or the immediate power source and cannot maintain operation in the event of grid failures. This is why hybrid inverters often provide more autonomy to the solar installations where they are used. 

- Energy efficiency: Hybrid inverters often have more advanced energy management features, allowing them to optimise the use of energy from renewable sources, the grid and batteries. This can result in higher energy efficiency and less energy waste. The charging mode function means that in the event of surplus solar energy, it is not lost but stored for later use. 

In short, while a grid-tie or "stand-alone" inverter only converts DC to AC current to power devices, a hybrid inverter offers additional functionalities, such as the ability to charge batteries and work in stand-alone or backup systems. This versatility makes hybrid inverters especially useful in solar and wind power systems, as well as in off-grid or grid-tied applications with back-up power needs.

How does a hybrid solar inverter work?

A hybrid solar inverter works as a combination of three main components: a direct current to alternating current (DC-AC) inverter, a battery charger and a power management system (also called a regulator). Its main purpose is to optimise the use of renewable energy (from solar panels or other sources) and energy from the grid (in the case of grid-connected) or diesel generator (when "off-grid"), while allowing excess energy to be stored in batteries for later use.

Here's how a hybrid solar inverter works:

- Solar energy harvesting: Solar panels (or any other renewable source) capture sunlight and convert it into electrical energy in the form of direct current (DC).

- DC-AC conversion: The hybrid solar inverter takes the direct current generated by the solar panels and converts it into alternating current (AC), which is the form of energy used in most devices and appliances.

- Real-time solar energy use: The energy generated by the solar panels is first used to power the devices and appliances connected to the system. If the solar energy production is sufficient, the energy will be fully utilised without recourse to the grid.

- Battery charging: If the solar energy production is greater than the energy demand at that time, the excess energy is used to charge the batteries connected to the system. This charging is DC direct current. It is important to note that the batteries store the energy in this type of current and NOT in alternating current (AC). This means that the current and voltage that charges the batteries does NOT go through the DC-AC conversion but is directly in DC.

- Use of grid power: When the solar energy production is insufficient to cover the electrical demand or if the batteries are discharged, the hybrid inverter automatically switches to grid power supply. This ensures a continuous power supply even when solar conditions are not optimal.

- Battery discharge at times of low production: During the night or on cloudy days when solar energy production is low, the solar hybrid inverter will use the energy stored in the batteries to cover the electricity demand. As mentioned above, the battery charging is DC, so the discharge will be DC as well. That is why when the batteries are discharged the current will have to go through the DC-AC conversion before feeding the loads. 

- Intelligent energy management: The hybrid inverter's energy management system continuously monitors solar energy production, power consumption and battery charge level. Based on this data, the inverter makes intelligent decisions on how to use the available energy as efficiently as possible.

In short, a hybrid solar inverter allows you to make the most of solar power, use grid power for backup, and store excess energy in batteries for a continuous and efficient power supply. This makes it an ideal choice for renewable energy systems with intelligent storage and management capabilities.

How long does a hybrid inverter last?

The lifetime of a hybrid inverter depends on several factors, including the quality of the device, its design and construction, proper maintenance and usage. In general, good quality hybrid inverters are designed to have a lifetime of at least 10 to 15 years.

Some factors that can influence the lifetime of a hybrid inverter are:

- Inverter quality: Inverters from well-known and reputable brands tend to have a better quality of construction and components, which generally translates into a longer lifetime.

- Environmental conditions: The environment in which the inverter is installed can affect its durability. For example, if it is exposed to high temperatures, humidity or extreme weather conditions, it can shorten its life.

-Load and usage: The amount of load and usage of the inverter can also have an influence. An inverter that operates near its maximum capacity on a constant basis may experience increased stress and wear.

- Maintenance: Proper maintenance and regular cleaning of the inverter can help prolong its life.

It is essential to read the manufacturer's specifications and recommendations, follow installation instructions and perform suggested maintenance. Some hybrid inverters may offer multi-year warranties, indicating the manufacturer's confidence in the durability of the product.

Remember that, like any electronic device, hybrid inverters may eventually experience failure or wear and tear over time. It is always advisable to consult a qualified professional or technician for installation and maintenance of the inverter to ensure that it functions properly and has an optimal lifespan.

At Tienda Solar we have hybrid inverters for every need. The catalogue includes cheap hybrid inverters and other more prestigious ranges at different prices. For more information please do not hesitate to contact us at info@tienda-solar.es.