What is an off-grid solar power system? Off-grid solar power system is a system that uses solar energy (green and clean energy) to provide stable power to AC devices when there is no grid or the grid is only used as a backup.
Building an off grid solar system is a difficult task that many people want but don’t know how to start. people want but don’t know how to get started. It is common for us to design and build off-grid solar power system in areas where there is a shortage of electricity or for the off-grid or for the concept of environmental friendliness, but how to build it reasonably? how to build it reasonably? This article will use the simplest language to help you answer several questions about building an off-grid solar power system. Renogy has been in the off-grid solar business for more than ten years. we have collected a lot of information on the sales of different off-grid information, has become a top solar panel manufacturer based in Louisiana that has grown at a rapid rate since its founding in 2010, finally presented a set of relatively reasonable off-grid solar power system solutions.
Note: This guide mainly describes the solar panel, solar charge controller, mppt solar inverter, solar inverter, solar generators and so on. it does not include the cables, connectors, brackets and some auxiliary materials.
Our guide is divided into the following two types of off-grid solar power system.
Small off-grid solar power system (300W-3000W).
Medium and large off-grid solar power system (5000W-45000W).
If you want to build a low cost off-grid solar power system to meet your daily electrical appliances, such as surveillance device, LED lights, electric fans, rice cookers, and refrigerator, this program will be right for you. It is popular in some power deficient or unstable areas in Asia, Middle East, Africa and South America, or in some Tiny houses in North America and Europe.
1. Design guide for a small 300W off-grid solar system (12V battery system)
- 1*300W mono/ polycrystalline solar panel.
- 1*30A Mppt solar charge controller.
- 1*100AH 12V gel battery or 1*50AH LiFePO4.
- 1* 300W pure sine wave inverter.
How much power does a 300 watt solar panel produce?
With an average daily sunshine of 5 hours at full load, this system can generate about 1.5kWh, please calculate the power generation of this solar panel according to the local sunshine situation. Without using the load, the 12V 100AH battery. it can be fully charged in about 4 hours. Assuming that our system is used for outdoor surveillance, usually a set of surveillance power is 20W, which also means that the power consumption for 24 hours is 0.48kWh. Since the inverter has a conversion efficiency, which we estimate to be 88%, monitoring 20W consumes about 0.55kWh per day. If you are in a place where there are 10 hours of daylight, this system will fully meet the daily monitoring work and can even support more than 48 hours in the absence of sunlight. If you need a longer time or a higher charge, you can increase the battery capacity. And the cost of this system is very low, suitable for off-grid solar power system with only low cost budgets.
2. Design guide for a 1kw off-grid solar power system (12V or 24V battery system).
- 2*300W mono/ polycrystalline solar panel.
- 1*60A @12V battery or 1*30A @24V Mppt battery solar charge controller.
- 6*100AH 12V ( 3*100AH 24V) gel battery or 1*100AH (2*50AH) LiFePO4.
- 1* 1000W power inverter .
What can run a 1 kw solar system?
1kw off grid solar power system is very popular in the market, CNBOU configure more than 10000 units pure sine wave inverter for 1kw system, which is good value, and the system is also very simple. The 1000W pure sine wave inverter can drive two 75W fans, five 20W LED lights, one 75W TV and one more than 600W rice cooker, meeting the need of a small family. If you have a refrigerator less than 100W, the 1000W BP inverter can work normally. The maximum power of the refrigerator is between 400W – 800W, it can easily work with the 1000W BP inverter. And the 1kw off grid solar power system is the most popular for off grid solar power system enthusiasts.
3. Design guide for a 2kw off-grid solar power system (12V or 24V battery system).
- 3*300W mono/polycrystalline solar panel.
- 10*100A @12V battery or 1* 50A @24V battery Mppt solar charge controller.
- 10*100AH 12V ( 5*100AH 24V) gel battery or 1*200AH (2*100AH) LiFePO4 battery.
- 1*2000W pure sine wave inverter.
How many solar panels do I need for a 2kW system? It depends on whether your system runs at full load for a long time or if you use it occasionally, such as: induction stove or kettle, etc. Because if we only use several minutes or less than half an hour, we don’t need to match the solar panel with the same power. A 900W solar panel can generate 4.5kWh electricity in 5 hours, the electricity consumption of a 2kW pure sine wave inverter in one hour is 2kWh, if only use occasionally, it will be enough. Of course, you can say I have many LED lights used in off-grid solar power system of the farm, you may need configurable 6 * 300W Mono / polycrystalline solar panel. Meanwhile, you need to replace the Mppt solar charge controller which is twice bigger. Here we recommend the Mppt solar charge controller. Although PWM is cheap, its efficiency is 20%-30% lower than mppt, which will lead to waste your solar panel.
4. Design guide for a 3kw solar system with battery (24V or 48V battery system).
- 6*300W mono/ polycrystalline solar panel.
- 1*80A @24V battery or 1*40A @48V Mppt battery solar charge controller.
- 8*100AH 24V ( 4*100AH 48V) gel battery or 1*300AH (3*100AH) LiFePO4.
- 1* 3000W pure sine wave inverter.
How many batteries do I need for a 3kw solar system?
Lead acid battery for 3kW solar system, in 24V declaration, 3000W/24V=125A, if you need to stay in best condition, and run at full charge for a long time, we suggest you use 125A*10H=1250AH , 13 batteries in parallel. If it’s 48V, you need 14 batteries, 7 in parallel and 2 in series. Such configuration can satisfy the operation of this system, and it is good for battery life. If you use 3000W load occasionally, only 1000W in normal, it will be ok to set according to 1000W system. It has little effect on battery life when used for a short time. Why do we need such a large battery system? If the charge and discharge current of the lead-acid battery is 0.1C, (most lead-acid battery charge and discharge current is 0.1C on the market), charge and discharge time is 10 hours, it is its own original design. We have tested, if you charge 100AH
battery with 40A Mppt solar charge controller, the battery is exhausted and unusable in less than 45 days.
LiFePO4 battery for 3kw solar system, LiFePO4 is different from lead-acid battery, it is designed with charge and discharge current 1C, (they also have charge and discharge current 0.2C-0.5C in the market). If you don’t need to work at 3KW for a long time, LiFePO4 battery is very suitable for the system. Its weight and volume is much less than lead-acid battery. 1C to charge or discharge
the battery for one hour will not affect the battery life. LiFePO4 battery can cycle more than 2000 times, even if cycled once a day, it can also be used for more than 6 years and keep its attenuation less than 20%. In this system, we only need one 150AH 24V (75AH 48V) LiFePO4 battery, which will save space and reduce cost.
5. How many batteries do I need for a 5kw solar system?
It depends on how long you need your system to run on batteries without any help. There are many types of 5kw off grid solar inverters in the market, what we see are generally two types:
- Solar panel input is less than 5000W.
- Solar panel input is greater than 5000W.
Off-grid solar power system with solar panel input less than 5000W (48V battery system)
Assuming your solar panel is 3000W, the electricity generated is 3kWh per hour, which means you need a 48V60AH battery to store. If your location has 5 hours of sunshine, the electricity generated each day needs 48V300AH battery to store, that is 15kWh, when the off-grid solar power system you design works for one day, when the battery is full, the Power obtained from solar power will be directly converted into AC power for charging. The battery is always full and is used at night when there is no solar power. 15kWh, supplying a 1000W load can be used for 15 hours. The cost of this system is low and practical. If it is a lithium iron phosphate configured battery the service life will be very long.
Off-grid solar power system with solar panel input greater than or equal to 5000W (48V battery system)
This type of design is generally for commercial or industrial use, which uses a lot of electricity during the day and basically does not need to be used at night. We have designed a 5000W input solar panel, which can generate 5kWh per hour, and most of the energy is directly converted into the load, and a small part is stored in the battery. Calculated on a daily basis for 5 hours of sunshine, it can generate 25kWh of power per day, and what battery capacity you need depends on the use of charging at night, but it produces 5kWh of electricity per hour even if you use a 1C lithium iron phosphate battery, need at least 48V120AH. Summary: what battery capacity needed for a 5kw off grid system? In addition to calculating the load usage when there is no solar or no grid, you also need to calculate the power to charge the battery per hour to achieve the best battery status. If the battery capacity is too small, it will be damaged very quickly.
6.How much power can you generate on your dock with an off-grid solar system?
When you need to install off-grid solar system on your boat dock, I think it’s a professional job. Boat dock is usually built without mains, if we have to request a transformer to power a boat dock separately, it will be very expensive to achieve. Therefore, choosing an off-grid solar system for free, eliminating the need to build a transformer to provide the grid (around $20,000) and not having to pay for the usual grid, is a good solution for your boat dock. Off-grid solar system at the boat dock of a solar power system can power the following:
- Boat lifts
- Lighting fixtures
- Air conditioning
- Washing machine, microwave oven
- Charging mobile phones, laptops, tablets
- Power tools
- Party accessories such as speakers, televisions
Many boat dock owners wonder whether off-grid solar system will cover all their use cases or not. The answer is yes. This off-grid solar system can work all year round.
How much power can you generate on your dock with an off-grid solar system? It depends on how many watts of solar panels you need to build. Dock owners usually only go to enjoy the dock life on off days, and hardly use any electricity on weekdays, just to power some camera or LED, and this can hardly be calculated, because it only takes a small amount of electricity. If we can use the off-grid solar system to generate 2kWh per day, we can store 10kWh from Monday to Friday, and 10kWh is enough for two days of electricity, and of course the off-grid solar system can also generate 4kWh in each Saturday and Sunday. Assuming 5 hours of sunshine per day in your local area, it would only take 400W of solar panels to generate 2kWh of power and store 10kWh of power, you need 200AH of batteries for a 48V battery system, providing an inverter big enough to do run most electrical equipment, such as a 5000W pure sine wave inverter. The following list mentioned (because in order to ensure there is enough power generation and the whole solar system will have some conversion loss, we will design a larger device.)
- 300W MONO or Poly solar panel *2
- 20A Mppt solar charge controller (12V/24V/48VDC Auto)
- 51.2V DC 200AH LiFePO4 battery
- 5kw pure sine wave inverter
This system configuration has a low cost and can be used for more than 6 years. The service life of solar panel, Mppt solar charge controller and pure sine wave inverter can reach more than 10 years.
7. What do I need for off-grid solar power?
If you need to set up an off-grid solar system, you first need to know your needs. How much load do you need to power and how long do you need this system to work for you when there is no external environment (no grid and no solar) to provide power? Only when you understand your needs will you be able to design an off-grid solar system that meets your expectations, and here are two options from which to choose.
Standalone off grid solar system
- Solar panel
- MPPT solar charge controller
- Solar Battery
- DC to AC inverter
The off-grid standalone solar system is composed of solar panel, MPPT solar charge controller, battery and pure sine wave inverter. The cost is low and the combination is flexible. This is a very flexible composition and your off-grid solar system will be very flexible and ready for future expansion. If you increase the load, then you need to increase the solar panels, at this time if the MPPT solar charge controller is not enough, you just need to replace a MPPT solar charge controller. Of course, if you feel that the pure sine wave inverter is not enough, you can also directly replace the pure sine wave inverter, no need to replace the whole system, or add a MPPT solar controller to connect in parallel It is also feasible, although it is not highly recommended, but in order to save costs, it is a way to balance. Of course if you add a load that can have independent lines.
All-in-one off-grid solar system
- Solar panel
- Off-grid solar inverter
- Solar Battery
An off-grid integrated solar system consists of solar panels, an off-grid integrated solar inverter, and batteries. The cost will be higher, but it is easy to install. The off grid solar inverter is a combination of MPPT solar charge controller and pure sine wave inverter in a stand-alone solution, which is very easy to install and will have more functions. The downside is that it will be less scalable and cannot be expanded, and if your system changes, the entire off-grid solar inverter will have to be changed.