How do VRLA solar batteries work?


Generating your own electricity from the sun is a powerful reward. Being able to relax in the afternoon on the weekend, look up at your solar panels and know that your vacuum cleaner will not cost a dime in a day, so you can rest assured.But what about when there is no sunlight at night? Unless you have energy storage, you will have to draw electricity from the grid or use no electricity at all. That’s why we need VRLA solar batteries in the system.

The storage system can also provide backup power for critical household loads during power outages. When used in conjunction with a solar panel system, solar cell storage solutions allow you to reap the benefits of renewable energy and apply it to household needs during power outages.

In this article, we show you how VRLA solar batteries work in a typical day. We will also outline the equipment needed for the solar backup system to work, and discuss the differences between grid-connected and off-grid systems.

Charge and discharge the VRLA solar battery in a typical day

Charge and discharge the VRLA solar battery

In the following example, we will show you how a typical VRLA solar batteries storage system works throughout the day.

In short, the solar plus energy storage system can keep the excess solar energy generated by your photovoltaic system during the day on site for later use at home.

In the daytime

In the early morning, because the sun has not yet risen, you will not generate solar energy.

Depending on the size of the battery and household usage, you may draw power from the grid and the battery at the same time. If you live in an area with low electricity bills during off-peak periods, you can program the solar batteries to charge during this time to save money.

Generally, energy consumption increases over time: take a shower in the morning, toaster, and then dry your hair. Since the sun is still low in the sky, you will not generate a lot of electricity from the solar panels. Grid electricity can make up for this shortfall.

In the afternoon, the day of the day is the day when your solar panels make money. Solar energy output is high, and because people tend to go out (as long as there is no pandemic to deal with), household electricity consumption is usually much lower.

During this time of the day, your home solar batteries can return to normal and can be recharged at night. You can also avoid sending money to the utility company, because electricity usually becomes more expensive from noon when the time billing plan is used.

In the evening

Charge and discharge the VRLA battery in the evening

As the sun begins to move toward the horizon in the evening, your solar production will decrease. At the same time this happened, household electricity consumption began to surge.

If your utility uses a time-of-use billing structure, the electricity price you pay during this period will be the highest.

Having a battery backup system here is very useful, because you can now use the solar energy stored in the battery at noon at home to meet the higher demand at night. By using your own battery power source, you can save a lot of money without having to pay expensive grid electricity bills.

At night, unless you are a night owl, your energy needs will decrease at this time. Depending on the size and usage of the battery, you can use grid power supply, battery power supply, or use both power sources at the same time.

If your electricity bill is really low in the middle of the night, you can set the battery to charge immediately and use the battery power in the morning to calculate the usage of the house.

Overview of the equipment needed for household VRLA solar battery storage

household vrla solar battery storage

In order for the home battery backup system to work properly, you will need some additional components. They are including, charge controller, battery pack and hybrid inverter (also called two-way battery inverter). Some hybrid inverters have a charge controller inside the unit.

Your solar panels generate direct current (DC). This is another type of electricity used by household appliances. They use alternating current (AC) and require an inverter to convert DC to AC and vice versa.

In a household battery backup system, the direct current generated by the solar panels is first sent to a special gadget called a charge controller. The charge controller will calculate how much power should be provided to your battery.

If the solar panel generates too much power to handle the battery, the charge controller will transfer the excess energy to the inverter. This is a good thing, because you can shorten the life of the battery by overcharging.

The hybrid inverter has an integrated charge controller. If the hybrid inverter detects a drop in power from the grid, it is sufficient to identify when to draw power from the battery. It also knows when it is not fully charged, when it is taken from the utility to charge the battery, and the sun cannot generate electricity well through the panel. The hybrid inverter can be programmed to route power to the battery according to the time of day, or it can be transmitted to the main circuit board.

When the grid is disconnected, some models can pass power from the panel to the battery, which can be connected to the circuit panel of the critical load. In this way, when the power is off, you can still power the required outlets at home.

On-grid and off-grid solar batteries systems

Compared with connecting it to the grid, if you want to promote solar battery backup systems outside the grid, you need to consider some differences. A well-designed off-grid system should be able to store enough power for two to three days at the coldest time of the year without too much sunlight.

Therefore, you need more battery capacity and more solar panels to charge them. This makes off-grid battery backup systems much more expensive than grid-connected solar systems. Unless you are in a remote area and being able to use the stored energy is worth it for you, the extra cost of a backup battery can be prohibitive.


If you are looking for greater energy independence and flexibility in the event of a grid failure, then the solar battery backup system will provide you with an excellent solution. The combination of solar system and battery is a match made in heaven.

These powerful systems can intelligently switch between the use of solar energy, battery storage and grid power. VRLA solar batteries allow you to avoid using grid power during peak hours, which can save a lot of electricity bills.

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