Jurnal Dinamika Vokasional Teknik Mesin Vol.
No.
April 2026, pp.
https://journal.
id/index.
php/dynamika/issue/view/96605 ISSN: 2548-7590.
DOI: 10.
21831/dinamika.
Experimental Study on the Effect of PV Tilt Angle on Mini Solar Power Bank Performance Putra Andi Kolala1.
Lathifa Putri Afisna2.
Wuwuh Saminto Wibowo3.
Aditya Septian Putra4.
Antonio Carlo5.
Fajar Bagas Pambayun6.
Fajar Nur Huda7 1,2,3,4,5,6,7Department of Mechanical Engineering.
Faculty of Industrial Technology.
Institut Teknologi Sumatera.
Lampung.
Indonesia
Article Info
ABSTRACT
Article history:
Solar panels are devices designed to convert solar energy into electrical energy through the photovoltaic (PV) effect, offering a sustainable solution for portable power needs.
This study investigates the effect of solar panel tilt angles on the performance of a mini solar cell power bank in Institut Teknologi Sumatera.
South Lampung.
Indonesia.
A 2.
5 W monocrystalline silicon panel was tested at tilt angles of 15A, 30A, and 45A.
Data on current, voltage, temperature, and power were collected at 30-minute intervals from 09:00 to 15:00 WIB over three separate clear-sky measurement days.
The results indicate that the 15A tilt angle produced the highest average current .
mA), voltage .
08 V), and power .
162 W).
The estimated charging time for a 3000 mAh battery was 93.
77 hours .
A), 116.
13 hours .
A), and 138.
04 hours .
A).
The 15A tilt is the optimal configuration for portable solar power banks in this tropical region.
Received March 31, 2026 Revised April 30, 2026 Accepted April 30, 2026 Published April 30, 2026 Keywords:
Mini solar power bank Monocrystalline silicon Photovoltaic Tilt angle Tropical climate Corresponding Author:
Putra Andi Kolala Department of Mechanical Engineering.
Faculty of Industrial Technology Institut Teknologi Sumatera 35365 South Lampung.
Lampung.
Indonesia Email: putra.
kolala@ms.
INTRODUCTION
Solar energy is an abundant resource that can be efficiently utilized to produce clean and sustainable electrical energy.
According to the Global Solar Atlas, the South Lampung region in Indonesia possesses excellent potential for solar energy utilization.
Data such as Direct Normal Irradiation (DNI) reaching 970.
9 kWh/mA per year and Global Horizontal Irradiation (GHI) reaching 9 kWh/mA per year illustrate the substantial amount of solar radiation reaching the surface in this area (Global Solar Atlas, 2.
Furthermore, the high average air temperature of 26.
3AC in the region contributes to the dynamic performance of solar panels.
By harnessing this potential, portable and smallscale solar applications, such as mini solar power banks, can provide reliable off-grid charging solutions while reducing dependence on fossil fuels (Marisa et al.
, 2.
Jurnal Dinamika Vokasional Teknik Mesin.
Volume.
11 No.
April 2026 | 32 The performance of a photovoltaic (PV) system is highly dependent on the amount of solar irradiance it receives, which is directly influenced by the tilt angle and orientation of the solar panels relative to the sun's position.
When solar radiation enters the Earth's atmosphere, it undergoes attenuation through scattering and absorption, altering the quality and quantity of the radiation spectrum (Rahardjo & Fitriana, 2.
To maximize the capture of direct and diffuse radiation, the PV panel must be oriented optimally.
Various studies have shown that adjusting the tilt angle according to the geographical latitude significantly improves energy yield.
Yadav & Chandel .
reviewed tilt angle optimization for PV systems globally and confirmed that latitude-based angles provide the best annual performance for fixed installations.
Gharakhani Siraki & Pillay .
reported that tilt angle optimization in tropical regions can improve annual energy yield by 5Ae15% compared to horizontal Specifically in Indonesian tropical conditions, the optimal tilt angle typically ranges between 10A and 15A to maximize irradiance while allowing for natural self-cleaning by rain (Fitri Dwi Kartikasari et al.
, 2023.
Saepulloh et al.
, 2.
Even though many researchers have worked on optimizing large-scale solar power plants, very few researchers have reported on the specific tilt angle optimization for micro-scale applications like portable solar power banks.
Hidayanti .
evaluated portable monocrystalline solar chargers with a 1350 mAh battery but did not compare the impact of varying tilt angles.
Marisa et al.
, .
examined mini solar panels for power banks but focused on panel size selection rather than tilt angle optimization.
No prior study has provided precise empirical measurement of current, voltage, and temperature fluctuations of mini PV panels at different angles throughout the day in a South Sumatran tropical The novelty and primary contribution of this study lies in: .
the experimental comparison of three tilt angles .
A, 30A, 45A) for a 2.
5 W monocrystalline PV panel under actual tropical outdoor conditions in South Lampung.
Indonesia.
the derivation of a full-day electrical output profile including current, voltage, power, and panel temperature.
the quantitative estimation of battery charging time as a practical performance metric for portable off-grid applications.
This data is very useful in designing more efficient, portable renewable energy devices for emergency use in equatorial METHOD This research employed an experimental method to evaluate the performance of a mini solar cell power bank by varying the tilt angle of the PV panel.
The experiment was conducted in Institut Teknologi Sumatera.
South Lampung.
Indonesia.
The independent variable was the tilt angle of the solar panel, set at 15A, 30A, and 45A.
The dependent variables measured were the output current .
A), voltage (V), panel temperature (AC), and the calculated power (W) and charging time.
In this study, solar irradiance was not measured directly using a pyranometer.
instead, it was monitored through light intensity measurements (Lu.
as a representation of the brightness level at the Jurnal Dinamika Vokasional Teknik Mesin.
Volume.
11 No.
April 2026 | 33 testing site.
It is important to note that this study did not include uncertainty analysis or statistical analysis in the data processing.
Furthermore, practical losses, such as shading effects, dust accumulation, and electrical wiring resistance, were not taken into account, focusing the observation purely on the measured output parameters at each specified angle.
The materials used included a 2.
5 Watt monocrystalline silicon solar panel .
imensions: 110 x 70 m.
with a rated voltage of 5 V and a rated current of 500 mA.
A mobile phone with a 3.
7 VDC,
3000 mAh lithium-ion battery was used as the load.
The circuit design integrated the solar panel, a blocking diode to prevent reverse current, a charging module (TP4056 modul.
, and the battery, as illustrated in the schematic diagram (Figure .
Figure 1.
Schematic Diagram of the Mini Solar Power Bank Circuit Data collection was carried out outdoors with the solar panel facing upwards at a height of 1 meter from the ground to avoid shading.
Measurements were taken at 30-minute intervals from 09:00 to 15:00.
To assess reproducibility, each tilt angle configuration was tested over three separate clear-sky Clear-sky conditions were verified by visual inspection and confirmed by consistent light intensity readings (LCD Digital Lux Meter AS.
A digital multimeter (Mastech MS8268 with accuracy A0.
DC voltage/curren.
was used to measure the current and voltage, while a digital thermometer (Noncontact infrared type with accuracy A1AC) recorded the surface temperature of the PV panel.
The power output was calculated using the standard electrical power as follows:
ycE = ycOyya Where:
ycE : Power .
cOycaycy.
ycO : Voltage .
cO) ya : Current .
While the total charging time was estimated by following equation (Hidayanti, 2.
Jurnal Dinamika Vokasional Teknik Mesin.
Volume.
11 No.
April 2026 | 34 yaEaycaycyciycnycuyci ycNycnycoyce (E.
= yaAycaycycyceycyc ycaycaycyycaycaycnycyc y 1.
ycaEaycaycyciycnycuyci ycaycycycyceycuyc Where battery capacity = 3000 mAh and 1.
2 accounts for charging inefficiency .
RESULTS AND DISCUSSION
The experimental results demonstrate the dynamic relationship between the time of day, the tilt angle of the solar panel, and the resulting electrical output.
The complete raw datasets for all three tilt angle configurations are presented in Tables 1Ae3 below.
Table 1 Measurement data Ae PV tilt angle 15A.
Light Intensity (Lu.
36,567 37,360 38,288 41,321 42,467 43,111 45,023 46,220 45,649 44,267
Time 09:00Ae09:30 09:30Ae10:00 10:00Ae10:30 10:30Ae11:00 11:00Ae12:00 12:00Ae12:30 12:30Ae13:00 13:00Ae13:30 13:30Ae14:00 14:00Ae15:00 Current .
A) Voltage (V) Temp.
(AC)
Power (W) Temp.
(AC)
Power (W) Temp.
(AC)
Power (W) Table 2.
Measurement data Ae PV tilt angle 30A Light Intensity (Lu.
36,455 36,309 36,188 37,221 39,060 42,151 43,076 44,231 45,608 42,252
Time 09:00Ae09:30 09:30Ae10:00 10:00Ae10:30 10:30Ae11:00 11:00Ae12:00 12:00Ae12:30 12:30Ae13:00 13:00Ae13:30 13:30Ae14:00 14:00Ae15:00 Current .
A) Voltage (V) Table 3.
Measurement data Ae PV tilt angle 45A.
Light Intensity (Lu.
32,002 36,344 37,177 40,221 41,060 42,122 44,005 42,118 43,057 41,147
Time 09:00Ae09:30 09:30Ae10:00 10:00Ae10:30 10:30Ae11:00 11:00Ae12:00 12:00Ae12:30 12:30Ae13:00 13:00Ae13:30 13:30Ae14:00 14:00Ae15:00 Current .
A) Voltage (V) Current and Voltage Analysis Figure 2 illustrates the fluctuation of current over time for the three tilt angles.
The 15A tilt angle consistently produced the highest current, peaking at 78.
2 mA between 12:30 and 13:00.
The average Jurnal Dinamika Vokasional Teknik Mesin.
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11 No.
April 2026 | 35 current for 15A was 38.
39 mA, compared to 31.
00 mA for 30A and 26.
08 mA for 45A.
This represents a performance improvement of approximately 23.
8% for 15A over 30A, and 47.
2% over 45A.
Figure 2.
Effect of Tilt Angle on Output Current over Time Figure 3 illustrates the voltage measurements followed a comparable trend.
The maximum voltage was recorded between 11:00 and 13:00 when the sun was nearly perpendicular to the panels.
The 15A tilt yielded a maximum voltage of 5.
21 V and an average of 4.
08 V, while the 30A and 45A angles produced averages of 3.
77 V and 3.
66 V, respectively.
The relatively modest voltage differences compared to current differences are consistent with crystalline silicon PV behavior, where short-circuit current is nearly proportional to irradiance while open-circuit voltage varies logarithmically (Green, 2.
These findings align with the equatorial geography of Indonesia, where a lower tilt angle captures the maximum DNI during midday hours (Suparwoko & Qamar, 2.
Figure 3.
Effect of Tilt Angle on Output Voltage over Time Temperature and Power Output Figure 4 illustrates the panel surface temperatures increased steadily from morning, peaking at 31AC around 12:00Ae13:00 for all configurations, then decreasing in the afternoon.
Average temperatures Jurnal Dinamika Vokasional Teknik Mesin.
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April 2026 | 36 7AC .
A), 29.
3AC .
A), and 29.
2AC .
A).
The temperature coefficient for monocrystalline silicon is typically Oe0.
45%/AC for maximum power (Green, 2.
The 15A panel recorded slightly higher temperatures .
7AC vs.
2AC for 45A), indicating marginally greater thermal derating, but its irradiance gain from the optimal tilt angle still substantially outweighs this thermal penalty.
Figure 4.
Effect of Tilt Angle on Temperature Output over Time Figure 5 displays the power output over time.
The 15A tilt angle generated the highest average power of 0.
162 W, peaking at 0.
407 W.
The 30A and 45A angles generated average powers of 0.
098 W, respectively.
Based on the average current, the estimated time required to fully charge a 3000 mAh battery from an empty state was calculated.
The 15A tilt required 93.
75 hours, the 30A tilt 13 hours, and the 45A tilt required 137.
93 hours.
Figure 5.
Effect of Tilt Angle on Power Output over Time Jurnal Dinamika Vokasional Teknik Mesin.
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April 2026 | 37 Charging Time These results are consistent with previous studies indicating that lower tilt angles are optimal for equatorial regions (Irwanto, 2.
However, compared to Hidayanti .
, who reported charging times of 74 hours for a 1350 mAh battery using a similar 250 mA panel, the charging duration in this study is significantly longer due to the larger battery capacity .
0 mA.
and the relatively low actual current output .
verage < 40 mA) compared to the panel's 500 mA rating.
This discrepancy highlights the real-world efficiency losses in small-scale PV systems due to atmospheric attenuation, conversion losses, and non-ideal solar tracking.
Figure 6.
Chargin time relation with tilt angle.
CONCLUSION
This study experimentally evaluated a mini solar cell power bank system under tropical outdoor conditions in South Lampung.
Indonesia.
Complete measurement datasets across ten 30-minute intervals from 09:00Ae15:00 were recorded for tilt angles of 15A, 30A, and 45A.
The 15A tilt proved optimal, yielding average current 38.
39 mA, average voltage 4.
08 V, and average power 0.
162 WAi improvements of 8% and 47.
2% in current over 30A and 45A respectively.
The 15A tilt gave the fastest theoretical charging time .
Future work should expand on these findings by integrating Maximum Power Point Tracking (MPPT), bifacial panels, or higher wattage modules to enhance practical viability for portable off-grid Furthermore, subsequent research will incorporate precise irradiance measurements to better correlate environmental input with system output.
This will be supported by a rigorous statistical analysis and uncertainty analysis to validate the reliability of the data and quantify the precision of the performance metrics in tropical climates.
REFERENCES