By | January 3, 2019
How Long to Charge 12v Battery with Solar Panel- Solar Battery Charger

How Long to Charge 12v Battery with Solar Panel- Solar Battery Charger

How long does it take recharge A 12v battery? In most cases, a solar panel that produces 1 amp of current takes 5-8 hours or more depending on the size of a battery. To get the most effective charging by a solar panel, you have to maximize the amount of current by keeping the board pointed directly to the sun.

Manually that will be little complicated because no all of us has time to look after a panel either it’s getting the proper sunlight or not. Also, where shades are occurred because of surrounded tree, brush, building, or mountains, its difficult to keep the same amount of light to charge a battery through the solar panel.

To solve the problem, we need to count some odds and calculates few things like current production of a panel, charging/discharging amount, etc. In this article, we are going to discuss these factors and other stuff to figure out a 12v batteries’ charging duration, how to charge it and more ? 

How long to Charge 12v Battery with Solar Panel

Without knowing the charging state, its impossible to tell you what it takes to charge a 12v battery with a particular solar charger.

How fast a solar panel could charge a battery depends on its current sourcing ability also.

So, we are assuming a fixed charging efficiency of a solar charger so determine what it takes to complete the charging. So,

Our solar charger offers 85% charging efficiency. So, panel’s output power will be 85w if it’s putting out 100w. If our charger output is 12v, its average output current will be,

85W/12V = 7.083A.

So, to charge a 200A-hr battery the calculation would take,


=28 hrs.

That is means a wholly discharged battery would take this time in direct sunlight to fully charge up.

This may be possible in some countries around the globe but initially not practical for most of the places. It’s an optimistic calculation that assumes proper panel ventilation and deducts few other inefficiencies, however, its decent beginner’s point calculation.

How to Charge a 12V Battery with a Solar Panel?

To charge a battery solar energy is a free and easy option to get. It requires a few types of equipment which are safe, easy to understand and affordable.

You need items like battery, converter and of course, a solar panel. Many local hardware shops and online stores serve thousand of brand items at different price point including warranty, customer service, etc.

A decent size quality solar panel for 12v batteries could be mount in your yard, near a cabin/ tent, on the boat and anywhere you need with direct sunlight. Here is a simple discussion about what you required to build a solar power system to charge a 12v battery.

1. Solar Panel

Choose a solar panel that offers the highest amount of features and power at your budget point. Also, make sure its easy to carry and operate single-handedly.

But that does not mean you have to get a flimsy one that neither has stability nor quality. Other than that your panel should be well rugged and able to produce more power even in low light condition.

You can choose a portable solar panel instead of a fixed one. Portable solar panels are best for transportation. But the power capacity and durability is exceptionally low. However, portable solar panels are cheap and flexible to use.

Solar panels that offer 12 volts are more or less inexpensive for better performance you can have 16v panel to get more faster performance.

You can buy a customized solar panel with the help of an expert also. This type of panels gives scopes to add or remove multiple panels and other items to get 100% service that you ask for, well in most cases.

2. Charge Controller

In current days. Most of the solar panel especially the portable panels comes with a charge controller. If your system does not come with a charge controller, then you should get one.

It’s for added performance and protection. This affordable piece of tool automatically disconnects the battery from the solar panel when it’s fully charged. Besides, the unit with max energy power point tracking (MPPT) circuit maximizes the energy from the system.

Remember one thing, get a controller that can handle more than peak amount of energy from the panel. If there is more than one panel make sure these can deal with the total amount of power from the cells.

3. Battery

There are different size and capacity of batteries available, but hence we are talking to 12v let’s stick on that. 12v batteries are useful for numerous charge and recharge cycle. A deep period 12v battery is designed to be discharged fully and later replenished without changing the electrolytes or internal plates.

If you are thinking of using car batteries (exsept the deep cycle one) with a solar panel, then skip that plan.

Typical car batteries are not made for continuous drain and soon after it may fall to hold any charge correctly. So, get a specific type of battery that could handle constant charge and discharge and be alright.

4. Inverter

A battery’s DC voltage is 12, but maximum household gadgets run at 120 volts of AC. If you add an inverter like as the cigarette lighter of a car, the stored power in a battery will help to charge any household devices.

Just look for some little things before getting an inverter. Like, the current flow provided by an inverter should be accurate to accommodate the load. Also, select one with multiple sockets.

5. Solar tracker

A solar tracker is a maximizer. It works to turn a solar panel to the sun, so it gets full light always.

We all know its nearly impossible in some places to get 100% sunlight for at least 6 hours constant. Especially if you live in a location near mountain, jungle or anywhere, whither sunlight obstacles by shades of something.

So, increase the effectiveness by getting a solar tracker and it’s inexpensive also.

A calculation before having the right solar recharger

An hour of sunshine is like one hour of music or 25 mins of talk. A battery of solar panel last years and could charge many gadgets like iPhone, game, Bluetooth, digital cameras, etc. A solar charger is relatively light and easy to move around or transport for travel purpose.

Fixed units that need to mount are slightly uncomfortable to shift due to its extensive body in most cases.

The rule for calculating the average charging time is,

Divide the amp/hour rating of the battery with charger rating (amp) and then add about 10% for the additional time to top off the battery.

Suppose you have a regular size of the auto battery and its about 30 amp hours. To calculate the time, a 12 watts solar charger, you need,

  1. Count the Ampere per hour of the charger: 12 Watts /12 Volts = 1 Amp.
  2. Count the division: 30 amp hours / 1 ampers= 30 Hours of direct sunlight.
  3. Add 10%: 3 hours.

Chargers in between 12- 15 watt is good for vehicles like cars, boats, RV’s, ATV’s including electric fences.

If you need to charge laptop and camcorders the 7 watts are good. For smaller cameras, cell phones, and smartphones 2 watts are perfect to have.

There is another formula to help describe how the solar energy works? The solar energy’s output is denoted by watts. It can be understood by multiplying the voltage by amperage.

So the calculation would be- VoltagesXAmperesXWattage

Assume, a 7-volt 30-watt solar panel with 10 by 22 inches size has a voltage around 7.65 and amp 2.75. The amount of wattage determines by how much an electronic device or device can turn out.

How Many Time Does the Solar Charge Give You?

The answer to the question is the size and number of the solar panels and the setup installed in your house or on the location you want to.

The weather condition of areas also a significant factor for solar charge.

During a rainy day, dark winter days or in snowfall can affect the actual capacity of a solar panel like energy absorbance and production. Also, the settings (wire, socket, etc.) depend on providing current flow to the battery good or bad manner.

The power radiation from the sun in mid-afternoon is generally at its peak point comparison to the early morning and late afternoon sunshine.

If the overall condition is excellent. Your solar panels could give the best performances if you live in a place with sunlight all year round. But some factors like blocking shadows from nearby things, unfit mounting of the solar system can deduct the energy output though.

Figuring the numbers of hours a solar charger depends on the mentioned factors explained earlier. Assume a 50 watts of solar panel in your house can receive min 6 hours of maximum sunlight and can generate 300 watts hours of power in a one-day average.

But it the solar panel gets 3 hours of daylight, then it will able to make 150 watts of power per day only.

How Is Big of a Solar Panel Needed to Charge a Deep Cycle 12 volt Battery?

Charging a 12 volt deep cycle battery its essential to consider factors like design, features and the cycle system, means the makeup of the deep cycle battery including the size.

This battery is the standard battery often use in cars, RV’s, troller boats, etc. this type of cell is designed to charge and recharged numerous times. They are rated according to amp hours.

That means how many amperes the battery can offer a fixed amount of time/hours. The most common battery in this category is 350 ah. This battery can deliver 35 amps of power over the set of 10 hrs of use.

Final words

A 12-volt solar panel is common and relatively ideal for charging a deep cycle battery. The correct way to calculate what size of panel you need you will calculate the powering load of the board multiplied the amount of time the panel gets to absorb energy from the sun.

During a bright sunny day, chances are the panels get 4-6 hours at least to charge a 12v. This range of battery can provide 12- 18 amps to deep cycle battery. So, in this manner, a full day of sun can lead to 5 hrs of use to the 350 ah battery.

So, the main thing is depending on the size and situation it takes a solar panel 5 to 28 hours to charge a 12 volt battery. Depending on your area and your budget get the high capacity best quality solar panel to charge batteries.


Hits: 268

Leave a Reply

Your email address will not be published. Required fields are marked *