How to Customise Your Home Solar System
1.Components of a home solar system
A complete home solar system consists of photovoltaic panels, inverters, storage batteries, and related accessories such as wiring harnesses and switches. It is also possible to choose only solar panels and inverter to work according to the needs of your home use, or you can choose a solution where the inverter and battery work together. The following article will explain in detail.
2.Selection of Inverter
The choice of inverter is the core issue of the whole home solar system, need to meet several elements to determine what type of inverter to use.
(1) The first thing that the inverter should satisfy is the total power demand of the household load. For example, if the total power of all the electrical equipment in the family is 10kw, then the power of the inverter should be at least 10kw. All the suppliers will ask the customers what is the total power of the family, but many people don't know what is the total power of the family. The simple way is to summarise the number of major power equipment in the home, such as several air conditioners, refrigerators, induction cookers, water heaters, dishwashers and so on. A simple estimation will give you an idea of the approximate household load power.
(2) Different countries for the power of the customary use of different units, China's main inverter power label is KW, if you are accustomed to using KVA, then do a simple conversion, 20kva * 80% = 16KW.
(3) Family load and grid is single-phase 220V/230V, three-phase 380V/400V, split-phase 110V/220V and other different phases of the electricity situation, you need to choose the corresponding type of inverter, single-phase inverter, three-phase inverter, split-phase inverter.
(4) Inverter is also divided into hybrid inverter and off-grid inverter (mainstream use of inverter), in order to simply distinguish how to choose, I only say a key point, that is, the off-grid inverter is not able to sell solar power to the grid, other than that there is not much difference. Hybrid inverters can sell power to the public grid in addition to fulfilling the functions of an off-grid inverter.
3. Selection of photovoltaic panels
The choice of photovoltaic panels is relatively simple, the mainstream photovoltaic panels are now using the latest technology, unless the individual has special requirements for the brand of photovoltaic panels, basically the brand can meet the demand. I on how to choose the family of solar panels of a few practical content to do the following description, not for professional data comparison.
(1) PV panel installation of total power selection, the first reference inverter PV panel access to the total power and each way voltage range. Secondly, it is best to choose the same number of solar panels for each MPPT. Thirdly, combine with the roof or installation area space area selection. Fourthly, combine the battery capacity and the total daily electricity consumption of the family, choose the number of solar panels suitable for your family.
(2) Solar panels are divided into single-sided and double-sided, double-sided solar panels generate more electricity, but if the installation location is a sloped roof, close to the roof installation in fact, there is not much difference between choosing single-sided and double-sided. Screen roof or ground mounted can choose double sided solar panels. The choice between all-black and normal solar panels depends mainly on the building style and personal preference.
(3)DC cable used for solar panels, it is recommended to use 6mm², it is recommended to choose the home version of the photovoltaic convergence box contains a short-circuit switch, surge protection switch, lightning protection function.
(4)Solar panel power generation estimation (without distinguishing between regional estimates), the total power * effective sunshine hours * conversion efficiency, for example: 10kw * 5 * 80% = 40kwh / day. For example, your family's power consumption in a day is 35kwh, can be matched with a 15kwh/20kwh battery, photovoltaic panels to generate electricity for the family during the day, the excess power to the battery to charge the battery at night the battery to the family power supply. You can realise a self-sufficient independent power supply system.
4.Battery selection
Battery is now the mainstream choice of lithium iron phosphate batteries, the choice of capacity is mainly based on the family's electricity consumption and budget decisions, the battery can be expanded at any time in the future through parallel or series connection capacity.
It is especially important to consider whether the battery can be matched with the inverter for communication.
(1)There are two types of batteries that can be matched to the inverter, one for high voltage and one for low voltage. You can check the batteries in the inverter datasheet, 51.2V for low voltage batteries and 96V-800V for high voltage batteries.
(2)Which one is better, low voltage or high voltage batteries, this is a question raised by many customers. For the battery itself, they are the same, are using the same material and type of lithium battery. The difference is that high-voltage batteries are connected in series, high voltage and low current, requiring additional high-voltage BMS control box, high cost. The low voltage battery is parallel connection scheme, low voltage, high current, low cost.
(3)For users who already have an inverter, the choice of battery can only be based on the type of battery that the inverter can match.
5.Different types of combinations to meet the needs of different households
(1)PV panels + inverter, this type of customer is mainly to meet the daytime electricity consumption or daytime electricity price is more expensive areas, the most common is the enterprise or factory. A large amount of electricity consumption comes from solar power. Or future plans to increase the battery users, must pay attention to this time the choice of inverter to be able to carry the battery inverter.
(2)Inverter + battery, this type of user selection is mainly for the daytime electricity prices are low, high electricity prices at night. Peak and valley arbitrage mode, the cheap electricity into the battery, the high price of electricity is suitable for the use of battery discharge. There is also for areas with frequent power outages, the battery acts as a backup power supply function.
(3)Solar panels + inverter + battery, complete solar energy storage system, basically can meet the self-sufficient power supply, off the grid, saving electricity bills, to achieve independent energy system.