Voltage Optimization of Nickel Metal Hydride Batteries through Motorized Direct Current Generator

Abstract

INTRODUCTION

Rechargeable batteries are useful in various electronic gadgets. However, prolonged usage of these batteries is limited due to their power capacities, i.e. the amount of charge they can hold for a certain amount of time. The purpose of this study is to create a device, the motorized direct current (DC) generator, which could significantly extend the usage of 4 Nickel Metal Hydride (Ni-MH) batteries under static and dynamic loads. This device has potential applications for gadgets that use Ni-MH batteries especially during emergency situations.

METHODS

This study focused on the construction ofa motorized DC generator that uses 4 Ni-MH batteries. It utilized an experimental research design where observations and measurements of Voltage, Current, and Power output of the batteries with and without the generator were made every 10 seconds for 5 minutes. The device performance to power static and dynamic loads were also observed for 15 trials, where each trial lasted for 2 minutes. The discharge rates of a fully charged 4 Ni-MH batteries were compared under two set-ups: (1) loads are directly connected to the batteries without the generator and (2) loads are connected to the batteries while the generator is on.

RESULTS

The results showed that the device output was at steady levels of 4.5 Volts, 0.75 Amperes, and 3.38 Watts, with 2,080 milli Amp-hours (mAh) as its total charge. Series connected 9 LEDs with 9 resistors induced 12,606 lux illuminances when powered by motorized DC generator. On the other hand, the 9 LEDs powered by the batteries without the assistance of the generator produced an illuminance of 10,974 lux. All 3 DC motors in parallel connection ran when powered by the motorized DC generator. However, only 2 out of 3 DC motors in series connection was ran by the generator. The batteries also had a discharge rate of 0.6 Volts when used directly on loads compared to batteries assisted by the device that resulted to 0.2 Volts discharge rate.

DISCUSSIONS

The motorized DC generator satisfactorily achieved the desired Voltage output that is greater than half of the Voltage input. Thus, power output (in Amp-Hours) used is relatively low and the batteries generate less heat. This implies that the generator will increase the battery life of Ni-MH batteries. The device can also power static loads like LEDs and dynamic loads like parallel or series connected DC motors. Lastly, the results indicate that the device slows down the discharge rate of Ni-MH batteries up to 33% efficiency.