How to charge a battery with a solar panel

In this article I will explain how to charge a battery with a solar panel, a simple step by step tutorial that will help you with this task.

Connecting the battery to the panels is a simple task. However, in order for the solar panels to be able to supply your battery, you must first calculate how many panels you are going to need. To do this you will need to find out the amperage of your battery and the capacity of your solar panels. Here’s how to do it.

First step, how many Ah does the battery have?

First of all, you must find out what is the amperage per hour rate of the accumulator or battery you want to charge. You must know that, a battery of the calls of wet cells, diminishes its amperage around 1% daily when we are not using it. So, for example, we would need a solar panel capable of generating 0.5 amperes per hour per day, in case we want to keep a 50 amp battery always charged. The disadvantage is that the photovoltaic solar panels are classified according to their capacity in watts, so we will have to apply a simple mathematical formula to solve our unknown.

If you want to convert the capacity of a solar panel from watts to amps, you must divide the capacity of the panel in watts by 15. For example, a solar photovoltaic panel with a capacity of 50 watts is capable of obtaining about 3.33 amps. Then, if we take into account possible obstructions during sunrise and sunset, bad weather and possible clouds that may come out during the day, a solar panel is capable of supplying about four hours of output per day. Thus, a solar panel with a capacity of 50 watts will produce 4 × 3.33 amps per hour per day, or 13.33 amps per hour. So, the panel will be completely sufficient to get our 50 amp battery, can remain with its full charge capacity to the maximum.

Second step, make the connections.

Once we have calculated our needs, we can now move on to making the connections. In the first place, you must connect the positive cable with a fuse, from the photovoltaic solar panel to the battery. In this way we will be able to prevent us before a possible explosion or fire of the accumulator, in the case in which a short-circuit in the cable takes place. Later the negative cable of the photovoltaic solar panel is connected to the negative terminal of the battery.

If it is necessary to interconnect panels to charge your battery, we recommend that you connect your solar panels in a parallel circuit. In this way, you will have the option of using panels with a lower cost and also lower power, thus achieving the same effect as with a solar panel with more energy.

To connect the panels in parallel, you must connect the positive wire of the first panel with the second one, and so on consecutively. Perform the same operation with the wiring of the negative pole, and finally link the remaining wires to the battery.

Now you must calculate the amperage of your solar anpels that are connected in parallel. You must know that the solar panels that have been connected in parallel circuits, continue conserving the same electrical tension, and the intensity of the current is added. That is to say, if we have five solar panels with a capacity of 5 amperes, we will get 25 amperes of power, and all of them would have the same constant voltage

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