Hybrid solar systems are a cross between off-grid (battery incorperating) and grid connected (without battery) solar systems.
The best thing about hybrid systems is the capability to export excess power from the charged battery and earn additional discounts from grid feed in tariffs. With off-grid solar systems, that energy goes to waste as the excess energy cannot be utilised. Grid connected solar systems cannot store energy so you get the best of both worlds!
In recent years we have seen two types of hybrid solar systems evolve, with slightly different methods of operation.
DC coupled solar systems are those where the energy produced from the panels in Direct Current (DC) is sent directly to charge the battery without being converted into Alternating Current (AC). When called into operation the battery then supplies that energy, still in DC, to the inverter for conversion into AC for use in your home or business. With fewer energy transformations, this is typically the most energy efficient type of system. A SolarEdge+LG Battery combination or SENEC Home V3 are examples of these these types of systems that we supply.
AC coupled solar systems are those where the energy is converterd from DC to AC by your solar system inverter. The battery system then monitors this output along with your home demand and determines when it can convert some of the spare energy back into DC though its own inverter, and into the battery. When called upon, the battery system then converts that energy back into AC for use in your home. A Fronius or SMA inverter with an Eguana Evolve is an example of this type of system that we supply.
We touch more on these systems specifically in these articles:
DC Optimizers are essentially very small inverters that sit underneath the solar panel, hidden from sight. Each solar panel has it's own optimizer.
The optimizers convert the AC power produced by the panels to DC power so it can be used by all of your household appliances. It is much more efficient than a single inverter as it allows for the monitoring of each individual panel, which means you can recognize and respond to any issues that may arise very quickly.
Optimizers also help to get the system ready for a battery as the DC wiring goes all the way to the central inverter.
Optimizers allow for larger strings of panels to be created, which means the system overall is better value as a larger string of panels is more cost effective than a smaller one.
String inverters are the most commonly used type of inverters and the most proven technology. However, they are designed so that the entire string only works as well as the worst panel. For example, if one panel is only working to 50% capacity, all of the panels will work to the same lowest sustainable current, from the shaded panel.
Advantages of String Inverters
- Good flexibility with design over large roof spaces.
- Very high efficiency.
- 3 phase cost effective options especially for larger scale systems.
- Low cost of installation.
- Remote system monitoring available for inverter output.
- Recognised brands offer good support and quality products.
- Proven technology.
Disadvantages of String Inverters
- No panel level monitoring.
- High voltage levels from the panels may present a safety hazard.
- All panels are only as efficient as the least efficient.
- If one panel goes down the whole string could cease operation.
- Older technology, service and support may not be as responsive as other types of products.
Microinverters are designed such that each panel in the PV array is independant of the next so that any kind of damage or fault to one will not affect the others. This provides greater resiliance; should one fail, the rest will continue to function normally and all are monitored individually.
Advantages of Microinverters
- A single malfunction does not have a huge impact on the rest of the panels.
- Lower DC voltage, rapid shutdown.
- The ability to use different panel models and makes in the system - excellent in the case of repair because the parts are then easier to source.
Disadvantages of Microinverters
- Higher component cost.
- More complex installation.
- Depending on area of installation, there may be issues with overheating in extreme heat.
- Increased reliance on good communications for reporting.
- Higher efficiency DC coupled battery changing is not an option.
Enphase Micro Inverters have proven to be some of the most reliable inverters on the market today and they are the only micro inverters we use and recommend. You can monitor your energy consumption, solar production and self consumption all from one convenient app.