Nowadays, solar panels are the most preferable and environment-friendly power source for charging batteries, whether for supplying small or large amounts of electricity.
Cars often use 12V batteries, which require 5 to 8 hours of charging time but the time range differs according to the supplied current and many other related aspects. The good news is, you can use a solar panel to charge this battery as well.
If you know how long to charge 12V battery with solar panel, it gets easier to measure the efficiency of solar power considering the panel size, panel capacity, output current, and battery size. This article is all you need to get a better idea about the charging time of a 12V battery with a solar panel.
Amp Hours and Battery Sizes
Batteries differ according to their sizes and Ah ratings. Every battery has a specific Ah rating which helps to calculate the charging and discharging time. Amp-hours define the delivered current of the batteries for a certain amount of time.
According to the amp-hour measurement, we have to choose the right solar panel with the necessary watt rating.
If you consider two 12v batteries of the same Ah rating but different output current, the battery delivering less output current will take less time to charge compared to the one delivering more output current.
The capacity of any battery decreases with the increase of current, and as a result, the supply also decreases after a certain period of time.
Measuring the Standard Solar Panel
Proper measurement of solar panels is necessary while you charge a battery because some essential features will affect the charging time. they are mentioned below –
Dimensions and Watt Rating
Size of solar panels is associated with watts which is essential to estimate the charging time of any 12V battery. The standard dimensions of solar panels are 65×39 inches which can be used to charge a 12V battery of 100 watts. For 100 Ah rating, the charging time will be 4.2 hours.
But if the dimension of the solar panel decreases, the charging time will increase for the same Ah rating and watt rating. In the case of commercial uses, the standard dimension is 77×39 inches, and they produce 250 to 400 watts per hour.
Besides the dimensions and watt ratings, it also differs depending on the models of different solar panels.
Number of Panels
Depending on the watt rating, you can also calculate the number of solar panels that you will need to charge a 12V battery because a single panel can’t always recharge a battery of high watt ratings in a short time.
If you consider a sunny day, any panel of 100 watts will provide 30 amp per hour to your 200 Ah battery on an average basis. For recharging your 12V battery, you would need a single panel of 300 watts or several panels that all together makes 300 watts.
Besides the number of panels, the charging time also differs depending on the weather conditions. On a cloudy day, the charging time will increase even if the ratings are the same as stated above.
Battery Types
Several types of batteries are used in cars or other devices being charged by solar panels. Besides the regular car batteries, deep cycle batteries are also used widely for suplying energy and power.
Regular car batteries are not safe to discharge more than 40% because it affects the battery life. They can’t provide a simultaneous flow of energy for a long time, and as a result, they can be charged at a short time with a solar panel.
But if you consider a deep cycle battery, things become different. These batteries can provide sustainable energy for a long time, and you can discharge them up to 80%. So, charging them with solar panels is a time-consuming task.
For charging your 12V battery with a solar panel, you should choose a regular car battery if you want fast charging, even if you get small bursts of current flow. But in case you want a continuous flow and have no problem with large charging time, deep cycle batteries are a better choice.
How to Charge Batteries with Solar Panels?
Often people think that solar power can’t provide much energy, but actually, it depends on the battery capacity. The more capacity your battery has, the more power it can store, whether from a solar panel or other sources of energy.
Along with a battery and a solar panel, you will also need an inverter and a charge controller while charging the battery.
First, you need to set up the solar panel, converter, inverter, and a 12V battery altogether. Make sure to connect them properly so that the connections don’t get short-circuited.
Connect the charge controller with the battery on one end and with the solar panel on the other end. The charge controller is for safe voltage regulation to keep the voltage within the standard limit. Besides, pulse width modulation occurs in the charge controller while charging the battery.
Using charge controllers is essential to prevent overcharging as it helps you to notice the amount of stored energy in the battery. It can also disconnect the whole charging system in case of irregular voltage regulation.
The main task of a converter is to convert the DC to AC. The solar panel delivers a DC supply that needs to convert into AC to charge the battery. Like the charge controller, the converter is also connected to the battery and the solar panel.
Things to Consider
There are a bunch of dos and don’ts that you have to maintain while charging a battery with a solar panel. These stated key points will help you charge a 12V battery in an efficient and effective way.
- Try float charging or trickle charging to ensure fully charged batteries. It is a process where charging and discharging occur together at the same rate, and thus, there is a rare chance of overcharging.
- If you first discharge the battery and then charge it with a solar panel, there is a possible chance of bulk charging that increases the voltage level over the optimum limit.
- Never plug the solar panel directly into the battery, and always use an extra socket while connecting those two. Otherwise, it will increase the voltage rapidly after a certain period of time, which can eventually damage the battery.
- Always use a charge controller to maintain proper voltage regulation. If the voltage regulation is not within the desired limit, unwanted electrolyte bubbling occurs due to the excessive production of hydrogen and oxygen.
- As a result, the battery along with the whole charging system can be destroyed after several uses and cause mild to serious accidents.
- Try to maintain a regular room temperature while charging batteries with solar panels. Because low temperature increases the resistance of the whole system, that can increase the charging time.
Final Words
You won’t find a specific calculated time range for charging batteries with solar panels because several factors are related to it. In this article, we have tried to provide you with all those factors so that you can measure how long to charge 12V battery with solar panel. Hope this helps!