Understanding how solar PV system connections are done will save you unforeseen frustrations. Solar PV system connections are complete when a solar panel, charge controller, solar battery, and an inverter. I have heard people claim that you don’t have to add all the devices to your system. However I have to differ with that theory.
Each device in a solar PV system have their specific purpose which ensures efficiency is achieved. In this article we answer some of the common asked questions about solar PV system components. If you are looking to do the connection by yourself please stick around.
Can I connect charge controller to inverter without battery?
You should never connect an inverter directly to charge controller. A battery acts as a connection between the two. Connecting an inverter directly to a charge controller might end up destroying both your devices.
Which ever type of charge controller you are using needs a battery as a reference for voltage and current sent to an inverter.
Maximum Power Point Tracking (MPPT) charge controller detects the voltage needed by a solar battery and ensures it passed that voltage to it. If a solar battery requires 12V to be fully charged, them MPPT allows that voltage to pass to the solar battery.
An Inverter on the other hand function is to convert DC into AC to power appliances. It also reduce the voltage sent from the solar battery to the appliance.
Suppose your MPPT detects the high voltage required to run an appliance like a refrigerator, if the sun is hot enough and the solar panel have the capability, then it might send the large voltage to the inverter. This might destroy your Inverter.
Pulse With Modulation (PWM) charge controller also need a solar battery as a connection to the inverter. PWM regulates the amount of current reaching the solar battery. It detects the voltage in the battery and send current accordingly. If the current sent to the inverter is very high, you inverter might record zero voltage or get damaged.
Which ever charge controller or inverter you are using, you will need a battery between it and the inverter. Otherwise, your Inverter might get damaged. Remember manufacturers do not give warranty for devices that get defective from wrong setup.
Does a charge controller work without a battery?
A charge controller cannot work without a battery. For your home solar PV system to work, you will need a solar panel, a charge controller, solar battery, and an inverter.
Smaller solar PV system can work perfectly with a solar battery, inverter and a solar panel. However, adding a charge controller makes things run efficiently.
A solar charge controller on its own doesn’t have the capacity to power your home. You will need a solar battery to store the solar energy collected during the day.
Charge controllers regulate the amount of current sent to the solar battery. If the sun is too hot, the charge controller will reduce the amount of current reaching the solar battery.
Suppose your solar battery is almost fully charged, the charge controller will stop more charging from reaching the battery. The battery then starts charging using a technique known as float Charging.
Charge controllers also detects when the solar panel is not collecting any solar energy. It then stops any charge from leaving the solar battery to prevent over discharging.
The main function of the charge controllers in the solar PV system is to prevent deep cycle batteries from;
- Over discharging
- And ensures the battery charge efficiently.
If you want your solar battery to last longer, you should connect it to a charge controller.
Solar Charge Controllers and Batteries: Are They Essential?
Solar PV system can work without charge controller but cannot work without a solar battery.
A solar battery stores the excess energy collected by the solar panel during the day. The charge is then used to power appliances when need be. You will therefore save the amount of money you will have paid for electricity.
Standard solar batteries last for 10-30 years if provided with good care. Among the devices that ensures a solar battery completes its life expectancy is charge controllers.
Charge controllers ensures your solar battery charge efficiently even on a cloudy day. They also stops any more current from reaching the battery once it is fully charged. Charge controllers also prevent your solar battery from discharging in case the battery is stored for long.
However small this devices are, they are essential. They also reduce the chances of your solar PV system causing fire from an overheating solar battery.
Do all types of solar charge controllers need batteries?
Charge controllers main function is to regulate the amount of voltage reaching the solar battery. They lack the capacity to hold excess charge used. Charge controllers are classified as MPPT and PWM.
PWM or pulse with Modulation charge controller balances the voltage and current between the solar battery and solar panel. If the solar battery needs 12V, the charge controller allows 12V to pass to the solar battery. It also stops any charge to get to the solar battery when it is fully charged.
MPPT or Maximum Power Point Tracking charge controller on the other hand detects even the slightest current from solar panel and sends it to the solar battery.
The two charge controllers cannot work by themselves. They need a solar battery to hold large amount of energy to power appliances.
Is an Inverter essential?
There are different types of inverters available in the market. Each of this inverters have unique features which makes them suitable for individual use.
Solar panel sends Direct current to a solar battery in one direction. Since appliances run in different sizes of current, an inverter is responsible for converting DC into AC which is used to power appliances.
Inverters also increases the run-time of your solar battery. If an inverter I’d connected to a solar generator, it reduces the noise produced by the generator.
Modernized inverters also come with a carbon monoxide shutdown safety switch. This switch detects any CO produced by a generator and shut it down before it cause any harm.
Inverters also reduce the voltage sent to appliances from a solar battery. This reduce the chances of your appliances causing home fires.
Sometimes, you can use inverters without solar batteries as well. This is achieved by a special inverter type called hybrid inverters.
Wrong setup of solar PV system is far much dangerous that we may think. Missing one step might cause fires and other hazards in our homes.
Solar PV system works best when a solar panel, charge controller, solar battery and an inverter are present. They should therefore be connected to the system to endure efficiency.
A solar panel collects solar energy from the sun and sends it to the battery for distribution. Therefore, your solar PV system cannot function without a solar panel. Unless, you are connecting your components to the electricity line or generator.
A charge controller regulates the amount of current and voltage reaching the solar battery from the panel. Controllers ensure your solar battery is not overcharged, over discharged and efficiently charged. They are also responsible for preventing fires.
Solar batteries collects the excess energy from the sun and stores it to be used for when need arise. Solar batteries ate also essential for distributing the power to other appliances.
Lastly, inverters converts Direct Current (DC) into Alternating current (AC) used to power devices.
As seen from the guide, each component has unique function and should be present in a solar PV system.
Eng. Matthew Joseph Nandirio is the Founder of walkingsolar.
After graduating from the University of Houston in 2002, matt started working as an electrical and electronic engineer for several multi-national solar energy companies.
He has a wide range of experiences including solar system requirement analysis, planning, maintaining, debugging and even solar device development through research.
He now shares his 20 years of expertise through his articles on the walkingsolar website.
Further, he is also the author of two books on Solar Technology, “Solar Power for Villages” and “DIY Solar System for Dummies”.