เข้าใจ Solar off grid มากขึ้น อธิบายด้วยภาพ เข้าใจง่าย

Summary

This video explains how off-grid solar systems work, particularly in areas without access to the grid like mountains or islands. It covers the role of solar panels in converting sunlight into direct current (DC) electricity, the importance of battery storage, and the function of charge controllers in managing battery health. The video also delves into different scenarios where the system charges or powers devices, depending on factors like sunlight availability and battery levels. Five key cases are examined to illustrate how the system adapts to varying conditions, ensuring sustainable energy use.

Takeaways

• 😀 Solar off-grid systems are used in areas without access to the electrical grid, such as mountains, islands, or remote farms.
• 😀 The system converts solar energy into direct current (DC) electricity, which is stored in batteries for use when there is no sunlight, like at night.
• 😀 A charge controller regulates the voltage to protect the battery from excessive charge that could lead to overheating and damage.
• 😀 DC electricity generated by solar panels needs to be converted into alternating current (AC) for use in household devices, typically using an inverter.
• 😀 Solar off-grid systems work in various scenarios based on energy production and battery charge levels, with five specific case studies outlined.
• 😀 Case 1: When the battery is not full and no loads are being used, all electricity generated goes into the battery for storage.
• 😀 Case 2: If the battery isn't full and loads are being used, part of the solar energy powers the devices, and the rest charges the battery.
• 😀 Case 3: In low sunlight conditions (early morning, late afternoon, or cloudy days), the system draws extra energy from the battery to power devices when solar generation is insufficient.
• 😀 Case 4: At night or when there is no sunlight, the system relies entirely on stored energy in the battery to power devices.
• 😀 Case 5: If the battery charge is too low (below a set threshold), the system will shut down to protect the battery, and no power will be sent to the inverter.
• 😀 It is crucial to size the battery capacity appropriately to ensure that the system can meet energy demands during low sunlight periods or at night.

Q & A

What is a Solar Offgrid system?

A Solar Offgrid system is a power setup that operates independently of the electricity grid. It's typically used in areas where electricity is not accessible, such as remote locations like mountains, islands, or farms. It can also be used by individuals who want to rely completely on renewable energy.

How does a Solar Offgrid system work?

A Solar Offgrid system works by converting sunlight into electrical energy using solar panels. The energy generated is in the form of direct current (DC) which is stored in batteries. This stored energy is later used to power electrical devices through an inverter, which converts DC into alternating current (AC).

What role do solar panels play in the Solar Offgrid system?

Solar panels are responsible for converting sunlight into electricity. They absorb sunlight and convert it into DC electricity, which is then either stored in batteries or used immediately.

Why do we need a charge controller in a Solar Offgrid system?

The charge controller regulates the voltage and current going into the battery to prevent overcharging and potential damage from excessive heat. It ensures that the battery receives the right amount of energy to maintain its health and efficiency.

What is the difference between PWM and MPPT charge controllers?

PWM (Pulse Width Modulation) controllers are less efficient, typically with about 60-70% efficiency in transferring energy to the battery. MPPT (Maximum Power Point Tracking) controllers are more efficient, with efficiencies of up to 95%, allowing more of the energy produced by the solar panels to be stored in the batteries.

Why do we need an inverter in a Solar Offgrid system?

An inverter is required to convert the DC electricity produced by solar panels into AC electricity, which is the standard form of electricity used by most household appliances. The inverter may also adjust the voltage from 12V or 48V DC to the standard 220V AC for household use.

What happens when the battery is fully charged in a Solar Offgrid system?

When the battery is fully charged, the charge controller reduces the flow of electricity to the battery to prevent overcharging. This phase is known as 'floating', where the current flow slows down to maintain a safe battery voltage level without causing damage.

How does the system behave when there is insufficient sunlight?

In conditions with little sunlight, such as early morning, late afternoon, or cloudy weather, the solar panels may not generate enough power. In such cases, the system will draw additional power from the battery to supply the necessary electricity to devices.

What happens at night when there is no sunlight?

At night, when the solar panels cannot generate power, the system uses the stored energy from the batteries to power electrical devices. The inverter converts the DC stored in the battery to AC, supplying power to the household appliances.

What happens when the battery voltage drops too low in a Solar Offgrid system?

If the battery voltage drops below a predefined threshold (e.g., 11.8V in a 12V system), a low-voltage disconnect or cutoff device will prevent further energy usage from the battery. This helps protect the battery from deep discharge, which can reduce its lifespan.