Although it seems very complicated nomenclature IP standards is only a division in double digits, where each digit indicates that it is being served to meet these regulations. For the first digit would be: 5 ingress of dust can not be avoided, but it must not enter an amount that interferes with the proper functioning of equipment. For the second digit 4 is placed theequipment in your usual workplace. You should not enter the water thrown from any angle to an average of 10 liters per minute and a pressure of 80-100kN/m for a time not less than five minutes.

Photovoltaic energy is produced by solar radiation using devices called photovoltaic cells. It is ideal for supplying all kinds of isolated houses, shelters, but also can be used to supply electricity on a large scale. We show the operating principle "In a semiconductor exposed to light, a photon of energy starts an electron, creating both a" gap "in the atom excitador. Normally, the electron quickly finds another hole to refill it, and the energy provided by the photon thus dissipates as heat. The principle of a photovoltaic cell is to force the electrons and holes to move towards the opposite side of the material rather than simply recombine in it: thus, there will be a potential difference and thus tension between the two sides of the material,as in a stack "The first ground application of a commercial installation of photovoltaic cell was developed in Japan in 1966. In the picture: 1 - PV Modules 2 - Regulation and Control 3 - Battery 4 - Inverter to power.... 220V

hen we talk about IP code (International Protection) we talk about an international standard (IEC 60529) which classifies the protection against external factors, solid or liquid, that has a component or electronic device; LED strips, controllers, meters, security cameras, etc.

This alpha-numerically standard has been designed to sort different levels of protection. Nomenclature starts with IP followed by two numeric values.

- Example IP68:

The first value ranges from 0 to 6 and indicates the protection against solid agents. In this case, strong protection against dust.

The second value is between 0 and 8 and indicates the protection against liquid agents. In this case the complete and prolonged immersion during the time specified by the manufacturer.

We could say that the larger the number is greater IP protection has a device.

In below table, we can see different IP protections levels available.

IPXX	First digit (IPxx)	Second digit (IPxx)
0	Unprotected.	Unprotected.
1	Protection against objects of> 50 mm diameter.	Protection against vertically dripping water.
2	Protection against objects of> 12.5 mm diameter.	Protection against inclined drip water up to 15°.
3	Protection against objects of> 2 mm in diameter.	Protection against water projected from any direction, up to 60°.
4	Protection against objects of> 1 mm in diameter.	Protection against splashing water any direction.
5	Ingress of dust is not entirely revented, but it must not enter in sufficient quantity to interfere with the satisfactory operation of the equipment .	Protection against water jets.
6	Dust tight.	Protection against strong jets of water.
7		Protection against complete immersion up to 1 meter for 30 minutes.
8		Protection against complete and prolonged immersion.

When calculating the life of a battery it will be necessary to know the number of charge cycles that can be performed until the battery does not begin to lose its capacity.
Depending on the type of battery these charging cycles can vary, the most common being the mobile batteries, manufactured Li-Ion or Li-Po, which have a duration of between 300 and 500 charging cycles according to model and manufacturer.
Once thisE limit we will notice how the battery loses duration of operation, arriving to lose up to 25% of its capacity of load.
At this point it will be necessary to evaluate a battery change.
It should be noted that usage and charging habits can significantly affect battery life. For example, factors such as heat, charge the battery several times a day without it is almost exhausted, etc. Will be affectedits duration.
Therefore, to get the most out of the battery we must know when a full charge cycle is performed, and try to avoid misuse of charge, to increase its useful life.
A charging cycle is considered when the battery has been discharged or its 100% charge has been used.
The manufacturers advise that the charge is never made below the 58% battery, since the battery voltage would not fall so lowTo, so you could end up winning up to 4000 charge cycles.
Tips to increase the life of a battery.

• Avoid extreme heat or cold or very long applications of the device.
• Charge the battery as often as you can.
• Fully discharge the battery from time to time.
• Do not let the battery run out completely before charging.

Below is a table with theDifferent voltages (V), charge cycles (C) and battery percentage (B).

Li-Ion or Lithium batteries are one of the most common batteries used today.
We can find this type of batteries in mobile phones, wireless headphones, SAIS, smart watches, cars etc.

Lithium is a very light metal capable of generating ions easily so it is ideal for the manufacture of batteries.

Unlike other types of batteries are a bit more expensive, but acThey are much smaller and lighter, capable of doubling the duration of a Ni-Cd.

Thanks to their composition can be manufactured in different ways, adapting to the device where they should be located, as well as its low memory effect makes them ideal for any type of device.

Summing up their positive points:

• Easy to find
• Many different sizes and shapes
• Small size