What Wattage Solar Panel is Required to Charge a 150Ah Battery?

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Solar energy brings solutions to power needs during electrical energy crises or in the cases of weak main electric grids. Through solar panels, we can generate electricity; and during sunshine hours, we can run all of our appliances. With a battery connected, the generated energy during the day can be stored during daytime charging hours and utilized at night. Read on to learn about how much solar energy is required to charge a 150Ah battery so it can be utilized as a backup to run your appliances.

To charge a 150Ah battery of 12 volts, you’ll need 1800 Wh of energy and a minimum of 360 watts from solar panels to charge the battery. You can use two solar panels of 200 watts each with this type of battery for charging it up via your solar energy system.

In this article, we will discuss these calculations in detail below. You can run basic household appliances, electronic gadgets, lights, and fans on this type of battery for hours as a backup power source. Charging it each day with solar energy will give you free-of-cost green energy.

Let’s have a look at the details regarding calculations and the technicalities behind choosing these panels for regular use.

How Much Energy Does a 150Ah Battery Store?

First, it’s important to be aware of how much energy a 150Ah battery stores. With this knowledge, you will then be able to design a solar energy system that can charge your 150Ah battery to use as a backup electrical power source. This particular battery has 12 Volts at its terminals under normal conditions, so 12V×150 Ah=1800 Wh. Therefore, a 150Ah battery stores 1800 Wh of energy within it, so you will need 1800 Wh of energy to charge your 150Ah battery using the solar panel.

Rate of Charging Current for a 150Ah Battery

Each type of battery is designed to charge at maximum rate of current. For a typical lead-acid battery, this rate is C/10 or C/20, which means that a 150Ah battery can either be charged at 15 amps or 7.5 amps (depending on manufacturer instructions). Other types of dry batteries can be charged at higher rates. In this article, we’ll strictly be discussing lead-acid batteries for these scenarios. Lead-acid batteries are mostly designed at C/10. You can buy a lead-acid battery from here if you don’t have one already.

If your battery is the Li-ion type, it can be charged at high currents. Currents for Li-ion batteries can go higher even at C/2. This means that a 150Ah Li-ion battery can be charged at 75 amps without damaging it. Again though, we will primarily be discussing lead-acid batteries for the sake of this article.

Solar Panels Needed to Charge a 150Ah Battery

Again, you will be needing 1800Wh of energy to charge your battery. For the sake of calculation, we’ll be going with 5 hours of peak sunshine during an entire day. So, to charge your 150Ah battery, you’d need 1800 Wh/ 5h = 360 W of power constantly for 5 hours to charge the battery. This means that a 360W solar panel at its maximum efficiency can provide 1800Wh of energy in the span of 5 hours.

The Type of Solar Panel Needed to Charge a Battery

Now you know that you need a minimum of 360 watts for your solar panel. The question following this knowledge becomes what solar panel rating will be enough to give you 360 watts? For this, you need to check the current rating of the solar panel of interest. As we have discussed, a battery can be charged at 15 amperes; therefore, you can choose solar panels that give you 7.5 amps and place them in parallel to make 15 amps total. A 200-watt solar panel has a current rating of around 8 amps, so you can place two solar panels of 200 watts each in parallel to each other to meet required current and power ratings. Buy a solar panel for these purposes here.

With these panel setups, you can have even more energy than 1800Wh and your 150Ah battery can be charged in just 5 hours during the peak sunshine hours of the day.

The Need for a Charge Controller to Charge a 150Ah Battery

A charge controller is a device that regulates the power so it can give continuous voltage towards charging the battery. As solar power is intermittent and the output of solar panels will be varying under different conditions, there should be a charge controller between the solar panels and the battery that can regulate the power input to the battery. You can buy a charge controller by clicking here.

For a 150Ah battery, it’s required that you have a charge controller that has a minimum current handling capacity of 20 amps and can give an output of 14 volts during charging. Also, it should have enough capacity to handle at least 25 volts at the input side (at no load) because you’ll be using two 200-watt solar panels in parallel. Each 200-watt solar panel has open circuit voltage of around 21.6 volts.

Using a 150Ah Battery as Backup Energy

A 150Ah battery can serve as a great electrical backup for running basic household appliances and gadgets. You can run 12 LED bulbs (each of 7 watts) for 20 hours, and 12 bulbs is more than enough to brighten a small house.

You can also run 12 LED lights and two fans continuously for about 5 hours on a 150Ah battery. Similarly, you can run your mobile charger, laptop charger, camera cell charger, and other electronic gadgets easily for hours without interruption. Charging these with solar energy will give you free and green energy.

Final Words

A 150Ah battery has 12 volts at its terminal, so it can store 1800Wh of energy. To charge a 150Ah battery, you’ll need 1800 Watts during peak sunshine hours. If you consider an average of 5 hours per day of sunshine, you’ll need constant power intake of 360 watts for 5 hours to charge your battery.

Ideally, you should install two solar panels of 200 watts each in parallel so that 15 amps of current can be achieved with a charge controller in between the battery and the solar panels. A solar panel will have around 21.6 volts (open circuit) and a maximum current of around 7 amperes.

A charge controller is necessary to regulate variable power from the solar panels due to changes in environmental conditions throughout the day. A charge controller should also have the capacity to handle a minimum of 20 amperes at the output, 25 volts at the input side, and a regulated 14 volts (during charging) at the output.

See Also:
How Many Amps Does a 25-Watt Solar Panel Produce?
Goal Zero Yeti 150 Solar Generator Review
How Many Solar Panels are Required to Run a 5-Ton AC Unit?

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