People use batteries as sources of power for electrical and electronic devices in their daily life. Nevertheless, these possess temporary supply limitations due to their state of charge (SOC). A technique used to determine the state of charge is counting amperes, identifying the amount of consumed and of missing amperes according to the initial capacity of the battery. An electronic load consisting of an operational amplifier and an IGBT were used in order to maintain a constant current in the battery discharge process, as well as a data acquisition system that specifies the time needed to obtain the variables of current defined by the electronic load, as well as the battery voltage. Without a heatsink, the Ice current of the IGBT does not remain constant, due to temperature increases exceeding 100°C in less than a minute. A dissipation system with and without ventilation was needed, and the one that kept the current constant was a heatsink for AMD processor with a thermal solution greater than 90W with active ventilation. The discharge curve was managed with it while maintaining the temperature of the IGBT at a maximum value of 46°C during the 4.5 hours, with a current of 4.19A. The initial capacity of the lead acid battery used was close to 19Ah, a little less than that defined by the manufacturer for the new battery (20Ah). One of the biggest problems in determining the state of charge by means of ampere counting is the accuracy of the sensor. To the current sensor used, you can implement filtering stages that improve the SOC value as future work. It should be used that the Vce is below the battery to be discharged. Therefore, this system could not be implemented in 2V batteries, because the Vce voltage in the IGBT exceeds 2V and cannot deliver a potential difference in the resistive load.

The estimation of the state of health (SOH) of lead-acid batteries for electrical energy storage is an important factor when planning their replacement and energy management. There are many methods to calculate this parameter. The novelty of this work is that it employs an optical method that produces compelling results showing the variation of the UVC transmittance of the electrolyte when the battery has different SOH levels, which is a novel alternative to the existing one of ampere counting, which is also experimented within this work.

The piezoelectricity allows the generation of electric power taking advantage of the movement of vehicles and pedestrians. Many prototypes have been made with piezoelectric generators, but at present, their commercialization and use has not been popularized due to their low power generation and energy losses. A design of an experimental prototype of an energy harvester with piezoelectric materials that reduces these losses and generates more energy thanks to the resonance with the beams is proposed in this article. An equilateral triangular tilde is designed such it will not deform when a force act on it. The tilde has four-cantilever beams, and it is designed to resonate with the natural frequency of the piezoelectric material. This is coupled to the piezoelectric device. The vibration generated on the beam, by average of a mechanical load, is used to generate more energy when it resonates. The piezoelectric is a ceramic material and generates a nominal power of 75 mW before placing it on the beam, and 375 mW after being placed on the beam. However, the energy collection circuit has losses due to its own consumption, the transmission of energy to the storage system, and in the mechanical system.

The objective of this research was to determine the thermal performance of a solar dehydration system that allows controlling the temperature for the dehydration of aromatic herbs such as mint. The use of a double chamber marquee allowed obtaining high thermal values, even with low radiation levels. For temperature control, a system of vertical mobile beds was used in order to reach the programmed temperature. This temperature was monitored using an embedded Arduino-type system that allows both monitoring and controlling motors, as well as recording temperature information. It was possible to keep the temperature approximately constant at 40°C, the ideal value for drying aromatic and medicinal herbs.