Off grid solar power system for homes

Off grid solar power system for homes - Grid connected energy from. the sun. Living off grid in Portugal is a common fenomeen. With a solar PV panel and battery prices going down the last years, it is affordable to go off grid.

A grid-connected with a battery backup solar system are very useful if de EDP stops giving the electric energy during breakdowns.

Off grid solar power system for homes

The big difference between a grid-connected system and an autonomous system is that with an independent system the generated energy is stored locally instead of being sent away on the grid. You need batteries for this storage.

Heavy batteries.
These batteries often called solar storage cells. These heavy batteries or accumulators then store the electric photovoltaic energy. Delivered during the day and releases it when you need it.

Off grid solar panel systems will become the norm anyway in the future. But for now, the main advantage of a fully independent system is that power is always available.

The biggest drawback of an autonomous system is in the event of a defect in your photovoltaic panel, inverter or battery, you are entirely without power. With a grid-connected system you switch 100% to your external electricity supplier.

Hybrid solar panel system: best of both worlds

You might know the hybrid system best with electric cars. It is initially an electric car, but there is also a fuel tank that, in the case of electricity shortage, keeps the car going with fossil fuel. A hybrid system works similarly only is the fossil fuel, in this case, a national power network connection as from the EDP.

Nowadays there are already hybrid systems that go a step further:

  • If there is not enough electricity generated, the battery will supplement itself to absorb any peaks (for example, at a lower rate at night).
  • If the battery is as good as saturated, the system will supply excess electricity to the grid.

This video is showcasing the features and benefits of the ground-breaking X-Hybrid solar battery storage inverter from SolaX. Learn more at

The PV inverter with integrated battery controller is the central heart and regulate how to distribute power. Imagine it is during the day and the photovoltaic panels generate 5kWh. The household appliances use 3kWh at that time.

The hybrid inverter ensures that the remaining 2kWh will be stored in the battery pack. When it is fully charged, the excess current enters the energy grid.

You turn on the washing machine in the evenings, but the sun disappeared. The panels do not generate anything anymore. At that time, the hybrid inverter checks whether the batteries contain power.

If this is the case, the washing machine will run on free electricity. Is the storage cell empty? The energy gomes from the commercial energy grid.

Off grid solar power system for homes

As an energy manager I become enthusiast from my post! But where to store all that generated power? It seems simple, or course in batteries.

Worldwide, more than 700,000 panels are installed every day again. But a PV panel supplies no energy at night. The need for electricity does not stop when the sun is down. To be able to use the power generated during the day when the sun is not shining, storage is crucial.

Saving energy is also better for the wallet. After all: for every kWh that you generate but that you do not consume yourself and therefore deliver to the grid, you get a feed-in fee of 5-7 cents per kWh on average. And that while you have to pay around 18 cents for every kWh, you buy from the supplier if you do not produce electricity from photovoltaic panels. A loss of approximately 12 cents per kWh!

But there is a problem with the storage of power. Batteries are expensive, and they wear out. Every kilowatt hour that you put in and get out of it, therefore, costs depreciation.

Although lithium LiFePo4 battery prices are falling rapidly and the number of cycles is increasing, battery storage will cost more than 5 cents per kilowatt-hour for a long time. Batteries are therefore not easily profitable. Choose the best battery for a solar energy system.

Season differences in generation and the home battery

A Tesla Model S battery is big enough to power a family for ten days. If more and more electric cars come in, they can, in theory, serve beautifully as an overflow area for surplus green electricity.

The growth of electric vehicles also seems to keep pace with the growth of the renewable energy supply. If you are the owner of an electric vehicle, you can use it as a power backup system. Vehicle to grid is a well-known possibility for meaningful storage of your green energy.

Not everybody has an electric car like Tesla or a Nissan Leaf for use as an off-grid power system. Then you have to buy the best batteries for solar power storage, calculated for your system.

Due to the large seasonal differences in the production of kWh / power, the home battery of, for example, 10kWh on an average summer day in June is too small to store the generated kWh. On the other hand, while you make too little kWh / electricity on an average December day to cover your consumption, you hardly use your battery on such a day. The differences are even higher if you compare an extremely sunny summer day with a very dark winter day.

This keeps a connection to 220V / electricity grid necessary to absorb the overproduction in the summer and to compensate for the lack of production in the winter. In other words: it would, of course, be a shame to want to operate without a 220V connection, because in the summer you then let off a lot of power if your battery is full. It would be unwise because you do not have enough power in winter because your battery never gets full.

Off grid solar power system for homes - Battery for storing photovoltaic energy

Meanwhile, there are many brands that provide a battery storage system set for photovoltaic panels. Not only Tesla who advertises a lot and knows how to market a product but also smaller (but also good) manufacturers of storage systems.

A number of brands of storage units for home are: TeslaRCT power battery, Beaut Solar, AGM SolarSMAIron EdisonJLM and offcourse LG.

What kind of battery size do you need now to store all your energy from the sun collecting electricity panels? More importantly: how big does the battery have to be for the whole year with my family not to be left without electricity? Calculating the storage cell is then necessary and what is also useful: what does such a battery yield.

Tesla module
With the Tesla module of 7 kWh, for example, you have enough storage capacity for an average household to provide up to 15 panels. You can count on it extensively, of course, but practice shows that suppliers like them make it easy. 7 kWh for an average family up to 10 kWh for a larger family with, for example, 25 panels on the roof.

Continue with the Tesla module because it has a high voltage in contrast to others. To store energy, however, you must have DC voltage again, and a battery converter is required.  In addition, there are multiple voltages of the off the grid storage systems

High voltage (above 100 volts)
Low voltage (under 100 volts, such as 48 volts, SMA system)

Both are safe and not better than the others.

Storage system.

Expectations are high about storage PV systems. Innovations tumble over each other in the media about an increasing number of charging and discharging cycles. The storage capacity of the home batteries, the price decreases by, among others, Tesla, which is making huge strides, areas of application and raw materials used. The battery technology Li-Ion won the battle or is another technique taking place with the turnover and as a driver of the sustainability and energy storage at home?

Storage system and its future.

The future of renewable energy is linked to the future of storage systems.
But how and when will storage systems for renewables turn the energy world entirely upside down? Because this is a technique that goes well ahead. And what obstacles do we still have to overcome, but above all, what opportunities are there? I see a world in front of me where each house has its battery or where the electric car helps with the overcapacity if the battery is too small (with a lot of sun with solar panels)

Smart Storage Solutions.

Smart Storage Solutions is indispensable for entrepreneurs, and you will see a video below where such a storage system is applied. Many organisations in sectors such as solar energy, wind energy, grid management, so-called smart grids, planning, installation, urban development, architecture and construction follow these opportunities and innovations with great interest.

Be independent of large energy suppliers.

Individuals who generate energy themselves, for example with the help of solar panels or water heater, prefer to keep this energy close to home. Their preference is to use the recovered power itself. And if that does not work, they prefer to store it in batteries before use. They can also imagine that they share the generated energy with the neighbours.

Saving costs.

Saving costs seem to be the most important motive for consumers to choose for the panels. They are happy to adjust their energy demand if money can be saved. They attach great importance to consuming the energy themselves. To be able to do that, it is sometimes necessary to adjust the moments of energy consumption.

Independent of the energy supplier.

You call this an autonomous system. This has been happening for a long time in situations where it really cannot be otherwise. An independent electricity power system is a system for the generation of energy from sunlight.

RCT power systems are an exelent example where no use is made of the power network. The set works autonomously and is ideal for a camper or another place where there is no fixed power connection.

Off grid connected alternatives.

Of course, you can use the old-fashioned generator if you do not have electricity. They do so in many countries. Because large parts of the world still have no electricity grid at all. Networks of poor quality, so power failures are the order of the day.

Then you do have noisy, smoking diesel generators. But always clean electricity, so that people can work undisturbed and can study in the evening. Read a book or watch TV? By saving the generated energy from solar panels in batteries, you benefit the most.

Why would you return your surplus of self-generated power at too low a rate if you can use it yourself at a later time?