INTERNATIONAL JOURNAL OF LATEST TECHNOLOGY IN ENGINEERING,  
MANAGEMENT & APPLIED SCIENCE (IJLTEMAS)  
ISSN 2278-2540 | DOI: 10.51583/IJLTEMAS | Volume XV, Issue V, May 2026  
Development of a Hybrid Energy Harvesting Electric Travel Bag  
for Portable Electronic Charging  
Assoc. Prof. Dr. Ir. Armin Sofijan, M.T.1*, Wirawan Adipradana, S.T., M.T.2, Sudirman Yahya, S.T.,  
M.T.3, Daeny Septi Yansuri4, Nurhaida, S.T., M.T.5  
1,2 Department of Electrical Engineering, Sriwijaya University, Palembang, Indonesia  
3,5Department of Electrical Engineering, Polytechnic of Sriwijaya State, Palembang, Indonesia  
4Department of Electrical Engineering, Faculty of Engineering, Palembang University, Palembang  
DOI: https://doi.org/10.51583/IJLTEMAS.2026.150500214  
Received: 20 May 2026; Accepted: 25 May 2026; Published: 15 June 2026  
ABSTRACT  
Your reliance on mobile phones, laptops and other handheld devices is becoming something of a matter of fact  
as you get intrinsic need to charge there things while traveling and having no access to grid electricity. The  
following study designed and investigated a hybrid energy harvesting electric travel bag integrating a  
polycrystalline solar panel, piezoelectric elements, battery, inverter and charging outputs. The qualitative case  
study was augmented by descriptive prototype measures. Methods included interviews with five electrical  
engineering informants, direct observations while interacting with a prototype, documentation of the design and  
testing process, and records from controlled experiments involving piezoelectric loading (up to 417 N), solar-  
panel battery charging (0-10A charger current), laptop charging (up to 61W load per laptop placed directly on  
top of the platform), and inverter loading (150 VA inverter driving resistive loads). Based on the interviews, you  
discovered that users want an easy-to-transport energy source that is reliable, safe and portable. It was observed  
and documented that energy inputs of solar and mechanical could be incorporated together in a transportable  
system. A technical record indicated the battery state of charge was comprised of the following where 18 V solar  
panel increased it from 0% to full over five test days & 5 V Increase a smaller battery (a kiosk) from 0% to full  
in two test days. The piezoelectric subsystem generated greater voltage as the mechanical load increased, at 5  
kg the average value reached 3.814 V for the parallel configuration. Testing was carried out with a laptop, which  
resulted in approximately a 19.8% state of charge boost after 20 minutes, and during inverter testing the metal-  
air power packs operated lower load over a longer period of time. Consequently, this research establishes that  
the Electric Travel Bag appears to be a viable additional portable charging system for use with renewable energy  
sources; however, various improvements in charging efficiency, power regulation, arrangement of components  
for prolonged usage without over-weight and electrical safety measures have potentiality as future works.  
Keywords: Electric Travel Bag; Solar Panel; Piezoelectric Energy Harvesting; Portable Charging System;  
Renewable Energy  
INTRODUCTION  
These days, portable electronic devices are a must-have for education, work, communication and travel. But  
their mobility is still restricted due to the battery capacity and limited charging infrastructure. This constraint is  
increasingly important during long distance travel, field work and outdoor activities, mobile emergency response  
or in areas with limited grid connection. Against this background, portable charging systems for energy  
harvesting and storage have emerged as a significant engineering challenge.  
Solar photovoltaics is amongst the most matured renewable power technologies for small-scale and portable  
electrical applications. Newer studies highlight that with improved conversion efficiency, lower cost, long  
durability and easy integration/reintegration with energy storage, photovoltaic systems are increasingly more  
feasible (Dada & Popoola 2023). According to International Energy Agency (IEA) solar PV technology is set to  
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constitute almost 80% of the global renewable power capacity growth in the period from 2025 to 2030  
emphasizing therefore its strategic importance for future energy system (IEA, 2025).  
Similarly, alongside solar harvesting piezo gadgets harvest mechanical pressure or vibration as well as human  
motion transforming it into electrical energy. Some research has indicated that piezoelectric devices are the most  
promising for low-power applications since they are capable of harnessing biomechanical movement that occurs  
as part of one's daily activity (Ali et al., 2024; Golabek & Strankowski, 2024) with a greater emphasis on  
wearable and human-motion energy harvesting. The energy generated by piezoelectric elements is generally  
small; however, the technology is interesting as a variable power supply in wearable and mobile systems.  
The Electric Travel Bag introduced in this paper contains two (solar and piezoelectric) sources in one mobile  
product. The system encompasses both a storage bag and a renewable-energy-based charging platform for  
electronics. Position within research landscape: The paper positions itself as a qualitative case study backed up  
by documenting prototype performance. It details the design, user perception, component performance and  
practical charging system feasibility of an electric travel bag.  
Research Problems  
• How can an Electric Travel Bag be designed to utilize renewable energy as an alternative power source?  
• How does the solar panel perform in generating electrical energy to support the charging system of the  
Electric Travel Bag?  
• How capable is the piezoelectric component in generating electrical energy from pressure or movement  
during bag usage?  
• How effective are the battery and inverter in storing and distributing electrical energy to electronic  
devices?  
• Can the Electric Travel Bag be used as a practical and efficient portable charging system for travel needs?  
Research Objectives  
• To design an Electric Travel Bag that can utilize renewable energy as an alternative power source.  
• To analyze the performance of the solar panel in generating electrical energy to support the charging  
system of the Electric Travel Bag.  
• To identify the capability of the piezoelectric component in generating electrical energy from pressure or  
movement during bag usage.  
• To evaluate the effectiveness of the battery and inverter in storing and distributing electrical energy to  
electronic devices.  
• To assess the feasibility of the Electric Travel Bag as a practical and efficient portable charging system for  
travel needs.  
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LITERATURE REVIEW  
Typically, a portable renewable charging system is composed of an energy conversion device, power-  
conditioning circuit, energy storage element and output interface. A solar energy system consists of a  
photovoltaic panel that converts sunlight into DC electricity and a battery, which stores the harvested energy for  
future utilisation. Since solar energy is intermittent, depending on weather, irradiance and time of day (Dada and  
Popoola 2023), energy storage represents a key component in photovoltaic systems.  
Studies on portable solar charging in recent years have pinpointed the need for safe but regulated output, battery  
management systems, and system-level integration. Kok et al. for stable output that portable handheld wireless  
charging device (2024), Chen et al. (2025) presents an optimal charging device with battery energy storage and  
real-time monitoring for portable power applications based on solar energy. These studies suggest that portable  
renewable charging is possible but should be done under a controlled setting, accounting for the stability of the  
charge, battery load specifications and user safety.  
Recent Studies on Portable Solar Charging Emphasize Regulated Output, Battery Management, and System-  
Level Integration Issues. Kok Et Al. Developed a Mobile Solar-Powered Wireless Charging System with an  
Algorithm for Steady Output. It Designed a Portable Solar-Powered Wireless Item for Interfacing and Presents  
Calculative Purpose Using a Matching Algorithm. Yasini Et Al. (2025) Proposed the Design of a Multi-  
Functional Solar Charging Device with Built-In Battery Energy Storage Capabilities, Capable of Real-Time  
Monitoring and Data Processing, Which Can Ideally Meet Portable Power Needs. These Studies Show the  
Technical Feasibility of Portable Renewable Charging with Careful Design Considerations for Stability, Load  
Needs, and Safety to Users.  
METHODOLOGY  
Research Design  
The research was conducted using a qualitative case study design confirmed with descriptive measurements of  
prototype performance. Case in Point: Development and Examination of an Electric Bag for Solar and  
Piezoelectric Powered Portable Electronics A qualitative approach was chosen to explore product design, user  
needs, perceived workability and real-world limitations of the prototype. Qualitative interpretation of system  
performance was supplemented by descriptive measurements.  
Research Participants  
Table 1. Research participants  
No.  
Participant  
Role in the study  
Electrical Engineering, electric power  
systems, renewable energy, and energy  
conversion  
1
Assoc. Prof. Dr. Ir. Armin Sofijan, M.T.  
Engineering design, electrical systems,  
and applied technology development  
2
3
4
5
Wirawan Adipradana, S.T., M.T.  
Sudirman Yahya, S.T., M.T.  
Daeny Septi Yansuri, S.T., M.T.  
Nurhaida, S.T., M.T.  
Electrical engineering, electronic systems,  
and technical product evaluation  
Engineering analysis, renewable energy  
application, and system testing  
Electrical engineering, energy systems,  
and portable technology applications  
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Data Collection Techniques  
• Interviews were conducted with research participants to identify needs, responses, perceived benefits, and  
concerns related to the Electric Travel Bag.  
• Observation was conducted by examining the product design, component placement, solar-panel operation,  
piezoelectric response, battery storage, inverter function, and charging output.  
• Documentation was collected from design records, photographs, component descriptions, and experimental  
testing sheets. The documented data included piezoelectric loading tests, solar charging tests, laptop charging  
tests, and inverter load tests.  
Data Analysis  
Examination of Qualitative Data Through Thematic Interpretation of Interviews, Observations, and Documented  
Results. Leading Themes Included User Need, Product Benefit, Energy-Source Integration, Usage Challenge,  
and Room for Development. Experimental Data Was Presented Descriptively by Using Mean Values Such as  
Voltage, Current, State of Charge (SOC), Load, and Operational Time. However, Due to the Reasoning That  
Some Raw Piezoelectric Voltage Entries Used Decimal Dots While Others Used Decimal Commas Format,  
Values Which Were Considered Clear Evidence of Being Decimal-Voltage Instances Were Normalised Before  
Averaging. Inverter Data Were Interpreted Descriptively, and Efficiency Was Not Calculated Since Current-  
Scale Calibration Warrants Additional Verification.  
RESULTS  
Interview Results  
The results from the interviews show that it is perceived as necessary, considering longer trips, outdoor activities  
and lack of access to electricity on grid. As participants observed, laptops and mobile phones provided the ability  
to control digital in-transit devices. And how in this sense, people looked at Electric Travel Bag as a fascinating  
invention, as it seamlessly marries the familiar function of a bag to charging blind with renewable-energy-based  
autonomous work. But, participants all so said the product should not be heavy, safe, portable and easy to use.  
Table 2. Summary of interview results  
No.  
Aspect Asked  
Interview Results  
1
User needs  
Users need a portable power source while traveling.  
The Electric Travel Bag can store items and charge electronic devices at  
the same time.  
2
3
4
5
Product benefits  
Energy source  
Solar panels and piezoelectric technology are considered attractive  
because they use renewable energy.  
Users are concerned about battery capacity, safety, bag weight, and  
charging time.  
Usage challenges  
Development potential  
The product is feasible to develop as a portable charging system for travel  
needs.  
Observation Results  
The simplest observation is that it was a prototype made of portable charging system infused with renewable  
energy components. The basic elements included a solar panel, piezoelectric material, battery, inverter and  
charging output. The solar panel harvested electricity from the sun, and the piezoelectric part developed voltage  
when it felt pressure or movement. Battery here acts as an energy storage device, and the inverter convert  
electrical energy (which is stored inside a battery) so that it could be used for charging applications.  
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Table 3. Summary of observation results  
No.  
Observed Aspect  
Observation Results  
The bag is designed as a portable charging system integrated with  
renewable energy components.  
1
Product design  
The solar panel can generate electricity, especially under direct  
sunlight.  
2
3
4
5
Solar panel performance  
Piezoelectric performance  
Battery and inverter  
The piezoelectric component can generate electricity from pressure or  
movement, but the output is relatively small.  
The battery stores energy, while the inverter converts energy for  
charging electronic devices.  
The product is feasible to develop, but improvements are needed in  
efficiency, safety, weight, and battery capacity.  
Product feasibility  
Documentation Results  
The Electric Travel Bag was confirmed to be a hybrid between a travel bag and renewable energy technologies,  
based on documentation. We put the solar panel on the outside of the bag so it can get direct sun. The  
piezoelectric layer was implemented as an alternative power supply from pressure or movement. The test  
describes how well the system was able to produce, hold, and transmit power.  
Table 4. Summary of documentation results  
No.  
Documented Aspect  
Documentation Results  
The bag consists of a solar panel, piezoelectric element, battery,  
inverter, and charging output.  
1
Product components  
The solar panel is placed on the outer part of the bag to receive  
sunlight directly.  
2
3
4
5
Solar panel placement  
Piezoelectric use  
The piezoelectric component is used as an additional energy source  
from pressure or movement.  
The battery stores electrical energy, while the inverter converts it for  
charging devices.  
Energy storage and conversion  
Product condition  
The product is functional but still needs improvement in safety,  
neatness, durability, and charging efficiency.  
Piezoelectric Testing Results  
Piezoelectric tests were performed under the application of loads 0.5 kg, 1 kg, 3 kg and 5 kg. The results have  
demonstrated that voltage leaves increased with the applied load. At either low or high load levels the parallel  
setup provided an increased average voltage. The setup of the series has a slightly higher calculating power (5  
kg) as recorded by a higher current. These results suggest that piezoelectric harvesting can provide  
supplementary power, but not at a level comparable to the solar source.  
Table 5. Average piezoelectric output under loading conditions  
Series  
(V)  
Voltage Series Current Parallel Voltage Parallel  
Load (kg)  
Pressure (Pa)  
(A)  
(V)  
Current (A)  
0.5  
1.0  
184.21  
368.42  
0.190  
0.283  
0.000  
0.000  
0.699  
1.137  
0.000  
0.000  
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1.5  
2.0  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
552.63  
0.297  
0.310  
0.969  
1.101  
1.294  
1.389  
2.325  
2.640  
0.001  
0.002  
0.003  
0.004  
0.004  
0.005  
0.006  
0.007  
1.369  
1.355  
1.661  
1.979  
2.110  
2.160  
3.412  
3.814  
0.001  
0.001  
0.001  
0.002  
0.002  
0.002  
0.004  
0.004  
736.84  
921.05  
1105.26  
1289.47  
1473.68  
1657.89  
1842.11  
Note. Values are averages from repeated trials. Decimal-normalized values were used for technically identifiable  
piezoelectric voltage entries.  
Solar-Panel Charging Results  
Solar-panel testing included an 18 V polycrystalline panel and a 5 V polycrystalline panel. The 18 V panel was  
tested over five days and increased the battery state of charge from 0% to 100%. The average solar input voltage  
was 18.20 V, and the average input current was 15.68 mA. The 5 V panel was tested over two days and increased  
the battery state of charge from 0% to 100%, with an average input voltage of 5.00 V and an average input  
current of 9.36 mA.  
Table 6. Summary of solar-panel charging tests  
Average  
Vin (V)  
Average  
Iin (mA)  
Battery Voltage Battery SOC  
Panel Type  
Test Records  
Range (V)  
Change  
18 V polycrystalline 45 records / 5  
panel days  
18.20  
5.00  
15.68  
9.36  
14.80 to 16.80  
0% to 100%  
5 V polycrystalline 18 records / 2  
panel days  
3.70 to 4.20  
0% to 100%  
Laptop Charging and Inverter Results  
For the laptop charging tests, we used a 4400 mAh battery from an Acer 4739 laptop. The average laptop state  
of charge across five trials was approximately 19.8% after 20 minutes. It can be seen the battery voltage drop  
from 16.45 V as average at charging session to 14.10 V after some time (20 minutes), while Average current  
decrease from 2.05 A to 0.89 A average testing of inverter that running in lower load has longer operating time  
as need [2]. It had an average operating time of 192 min at 5 W, 181.2 min at 10 W, and a maximum of 166.4  
min at 15 W [110] and from it we can also measure the battery capacity which was lower to load task more  
output voltage stability in smaller loads as opposed high loads pointing directions doc that ensure good voltage  
regulation adequate load compatibility.  
Table 7. Average laptop charging results  
Charging  
(minutes)  
Time Average  
Voltage (V)  
Battery Average  
Current (A)  
Battery Average Laptop SOC  
(%)  
5
16.45  
15.43  
14.10  
2.05  
1.84  
0.89  
0.0  
10  
20  
11.0  
19.8  
Table 8. Average inverter load-test results  
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Load (W)  
Average Vout (V)  
Average Operating Duration (minutes)  
5
100.48  
92.46  
27.97  
24.23  
192.0  
181.2  
166.4  
142.2  
10  
15  
20  
DISCUSSION  
The results shows that the electric travel bag can be develop into hybrid renewable –energy charging product  
The insights from the interviews confirm that it is relevant because users really need electricity on the go. It  
follows research carried out on portable solar charging systems that argue for alternative power methods to be  
reliable when used in outdoor, emergency and off-grid scenarios (Kok et al. 2024; Rehman et al. 2025).  
The most critical energy source within the prototype is the solar subsystem. For the 18 V panel, you are able to  
find that it successfully helped to increase battery state of charge across a longer term (over a number of days),  
while for the 5 V panel, in just two days it was capable of incrementally charging over a smaller battery. The  
results endorse the deployment of a photovoltaic system as the main renewable source for portable electricity  
charging applications. Importantly however the degree to which your panels will top up the battery is highly  
dependent on sunlight intensity at the time of charging, the orientation of your solar panel and how long you  
charge. So, future units should employ a proper charge controller and maximum power point tracking while also  
incorporating protective circuitry for increased efficiency and safety.  
Although the piezoelectric subsystem yielded complementary output it was not adequate to be used alone as  
energy source. It produced higher average voltage than it does under the same mechanical load in parallel 3.814  
V at 5 kg. This output is in agreement with the literature, where piezoelectric harvesting from human motion can  
supply low-power devices or self-powered sensing, but generates an insufficient amount of energy for larger  
loads (Ali et al., 2024; Zhao et al., 2023). Consequently, piezoelectric elements are better auxiliary harvesters  
and not the main power source in the Electric Travel Bag.  
The Laptop charging results show that the prototype is capable of electronic charging, but performance again is  
unexciting In testing outlined, the system increased the laptop's charge state by around 19.8% after running for  
20 minutes. In conclusion, such a result indicates an applicability feasibility primarily for usage in emergency  
or short-term charge up cases. Yet, the diminishing both voltage and current of battery while charging implies  
betterment in terms of battery capacity, voltage regulation and including thermal protection.  
The Inverter Results Imply That This Is Just What We Ought to Anticipate, Since the System Spent Longer at a  
Reduced Load (But for Good Reason). Nonetheless, Significant Output Voltage Drop at Higher Loads Suggests  
This Inverter Subsystem Requires More Appropriate Sizing and Load Matching. We Should Perform Future  
Tests with Calibrated Measurement Instruments to Verify Voltage, Current, Power, and Efficiency. Electrical  
Safety Also Needs to Be Improved by Means of Insulation, Cable Protection, Fuse Installation, Load Protection,  
and Enclosure.  
At the Same Time, the Electric Travel Bag Is a Valid Case-Study, as Concept Goes but Still Needs Some  
Engineering Work Before It Will Get Used in Large-Scale. The Main Upgrades Include Charging Efficiency,  
Leading Edge Integration, Mechanical Robustness, Comfort of Use, Weather Tolerance, and Electrical  
Protection. Redesign the Product Such That: It Has an Optimal Tilt Angle of the Solar Panel, Piezoelectric  
Components in High-Pressure Contact Points, and Battery-Inverter Secured.  
CONCLUSION  
This Study Proposed and Evaluated a Hybrid Energy Harvesting Electric Travel Bag with Function of Portable  
Electronic Charging. The Results Indicate That the Product Is Viable as an Add-On Charging System Based on  
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Renewable Energy Sources. Interviews Suggested a Need for Travelers for Practical, Safe, and Portable Power.  
It Was Observed and Documented That the Prototype Synthesized Solar-Panel/Piezoelectric, Battery, Inverter,  
and Charging-Output Components. The Solar Panel Was the Primary Energy Harvested and Then, Secondary to  
the Pressure and Motion Piezoelectric from Which They Also Obtained Energy. The Energy Conversion and  
Storage Was Enabled by the Battery, and Its Distribution Was Facilitated by the Inverter, with Some  
Improvements Needed on Both Voltage Regulation/Maximum Power Tracking and Load Compatibility. In  
General, the Electric Travel Bag Has Applications That Students and Workers May Find Useful with Their Gbon  
or from Travelling, to Outdoor Users as Well as Providing Emergency Responses. The Next Frontier for  
Development, However, Lies in Making Charging More Efficient, Reducing the Time It Takes for a Battery to  
Reach Full Capacity, and Optimizing Electrical Safety and Layout. The Overall Durability, Weight, and  
Usability Ergonomics Need Work Too.  
Practical Implications  
The Study Provides a Practical Reference for Developing Renewable-Energy-Based Portable Charging Products.  
For Engineering Education, the Prototype Can Be Used as a Project-Based Learning Model Involving  
Photovoltaic Systems, Piezoelectric Energy Harvesting, Energy Storage, Power Electronics, and Product Design.  
For Product Development, the Study Indicates That Hybrid Renewable Charging Bags Should Prioritise Solar  
Energy as the Main Source and Use Piezoelectric Energy as a Supplementary Source.  
Limitations and Future Work  
Limitations: This Study Is Limited by a Small Number of Informants, the Case-Study Design, and the Fact That  
Prototype Measurements Constitute Descriptive Outputs. Calibrated Instruments Are Necessary to Confirm  
Certain Recorded Electrical Values. Future Work Should Include Controlled Outdoor Testing Under Measured  
Irradiance, Long-Term Durability Assessment, Comparisons of Different Panel Sizes and Piezoelectric Layouts,  
Measures of Real Output Power and Efficiency, as Well as Field Trials to Ensure That User Comfort Is Assessed.  
Declarations  
Funding: This manuscript has not specified external funding. Replace this statement if funding was received.  
Conflicts of Interest: The author(s) declare no conflict of interest.  
Data Availability: The data supporting the findings are available from the author(s) upon reasonable request.  
Ethical Statement: The study used non-sensitive expert input and prototype performance documentation.  
Institutional ethical approval requirements should be confirmed before journal submission.  
Acknowledgement: The author(s) thank the research participants and technical contributors who supported the  
development and documentation of the Electric Travel Bag prototype.  
REFERENCES  
1. Ali, A., Iqbal, S., & Chen, X. (2024). Recent advances in piezoelectric wearable energy harvesting based  
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2. Dada, M., & Popoola, P. (2023). Recent advances in solar photovoltaic materials and systems for energy  
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