ABSTRACT
The development of solar energy to meet the various needs of human life is currently increasing.
Solar Power Plant technology has also been widely found and applied in the community. Most
rural communities in the northern part of the Nigeria have the highest number of low-income truck
pushers otherwise known as wheelbarrow pusher, who takes luggage from place to place around
a market square go back home with little or no income. The aim of this project is to design and
construct a solar based wheelbarrow for rural community users that will enable the wheelbarrow
pusher utilize the solar energy while working to generate more income by charging small gadget
devices like phones, music box etc. This is achieved with a 50watt solar panel connected to charge
a fabricated 12V 20Ah lithium ion cells through a 20A charger controller, a dc-dc bulk converter
to provide 2A and 5v to two USB port, and two 12V dc jack for two lamps.
METHODOLOGY
Firstly, the battery cells are packed and connected in series and parallel in the order of 3S5P(3
series and 4 parallel) to give an output voltage of 12.6V and soldered on a 20A battery management
system (BMS) for even-charging and protection of the cells. A 50watt panel was sized suitable to
charge the system for a shortest time was connected to the BMS through a 20A charge controller
to constantly charge the battery and keep battery voltage at float when fully charged. There is a
display that shows the battery level, a two 5V 2A USB slot provided by a DC-DC bulk converter
for charging of handset and other devices and a two 12V output dc jack for 3W, 12V dc lamps
attached with a switch to turn-on the lamp. The system is described in the block diagram below.
BLOCK DIAGRAM
To calculate the charging time of a smartphones and normal 2G phones you should have proper
information about the output of the charger and about the battery capacity of a phone.
First, you will have to calculate the output of charger in watts. To calculate you should use this
formula
5𝑣𝑜𝑙𝑡𝑠 × 2𝑎𝑚𝑝𝑠 = 10𝑤𝑎𝑡𝑡𝑠
After calculating power in watts of charger now you will have to calculate the wattage of battery.
Use same formula i.e. 𝑉 × 𝐴 = 𝑊
Most smartphones have an average capacity of 4000mAh:
So therefore, a phone with 4000mah battery and Voltage at a nominal voltage of 3.7V then the
capacity is shown below
3.7 × 4000 =
14,800
= 14.8𝑤𝑎𝑡𝑡𝑠
1000
The wheelbarrow USB charger ports has a voltage regulator charger of output 10 watts and your
battery is of 14.8 watts. Now divide battery watt / charger watt
𝑖. 𝑒
14.8
= 4.8 ℎ𝑜𝑢𝑟𝑠 𝑎𝑝𝑝𝑟𝑜𝑥
10
This calculation is approx because there will be some loss.
So, If you charge a battery of capacity 4000mAh then it will take 1.48 hours
(1.48 × 60 = 88,80𝑚𝑖𝑛𝑢𝑡𝑒𝑠 ≈ 1ℎ𝑟29min)
Note; this is only applies to turbo, dash and other kind of batteries but for lithium battery (Rahit T,
2020)
Is 1hours 29 minutes + 30minutes= 1hr59min _(Vishwas N, 2020).
S/N
Handset
Battery
Size in
mAh
Battery
Capacity
in Watt
USB
Capacity
in (Watt)
Time (hours)
Nominal Time
to charge in
(minutes)
Cost of charge N50
kobo per min & per
day (Naira)
1
Samsung
Galaxy
5000
18.5
10
1.85
141.00 (2.21hr)
70.50 ×8=564/day
2
Apple
Iphone 13
4352
16.102
10
1.61
126.60 (2.7hr)
63.30×8=506/day
3
Huawei
Mate 10
4000
14.80
10
1.48
118.80 (1.59hr)
59.50×8=476/day
4
LG V30
3300
12.21
10
1.221
103.26 (1.43hr)
52.63×8=421/day
5
Google
Pixel
2000
7.40
10
0.74
74.40 (1.14hr)
37.20×8=298/day
6
Small
techno
1500
5.55
10
0.56
63.60 (1.4hr)
31.80×8=254/day
7
others
1000
3.7
10
0.37
52.2 (0.53hr)
26.10×8=209/day
Table 1: capacity of phones, their duration of charging and cost of charging
Additional cost of charging of a phone on a Solar Wheelbarrow when the sun is down
𝑻𝒉𝒆 𝒕𝒐𝒕𝒂𝒍 𝒏𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒓𝒆𝒄𝒉𝒂𝒓𝒈𝒆 =
(
𝑳𝒂𝒃𝒆𝒍𝒆𝒅 𝒄𝒂𝒑𝒂𝒄𝒊𝒕𝒚 𝒐𝒇 𝒕𝒉𝒆 𝒔𝒐𝒍𝒂𝒓 𝒘𝒉𝒆𝒆𝒍𝒃𝒂𝒓𝒓𝒐𝒘 𝒃𝒂𝒏𝒌 × 𝟑. 𝟕
)
𝑶𝒖𝒕𝒑𝒖𝒕 𝒗𝒐𝒍𝒕𝒂𝒈𝒆 𝒐𝒇 𝒔𝒐𝒍𝒂𝒓 𝒘𝒉𝒆𝒆𝒍𝒃𝒂𝒓𝒓𝒐𝒘 𝒃𝒂𝒏𝒌
×
𝑬𝒇𝒇𝒊𝒄𝒊𝒆𝒏𝒄𝒚 𝒐𝒇 𝒃𝒂𝒕𝒕𝒆𝒓𝒚
𝑩𝒂𝒕𝒕𝒆𝒓𝒚 𝒄𝒂𝒑𝒂𝒄𝒊𝒕𝒚 𝒐𝒇 𝒅𝒆𝒗𝒊𝒄𝒆
Considering average smartphones = 4000mAh
Efficiency of lithium battery=0.99
Wheelbarrow bank=20000mAh
𝑻𝒐𝒕𝒂𝒍 𝒏𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒄𝒉𝒂𝒓𝒈𝒆 =
𝟐𝟎𝟎𝟎𝟎 × 𝟑. 𝟕 𝟎. 𝟗𝟗
×
= 𝟑. 𝟔𝟔𝟑 𝒄𝒉𝒂𝒓𝒈𝒆
𝟓
𝟒𝟎𝟎𝟎
𝑫𝒖𝒓𝒂𝒕𝒊𝒐𝒏 𝒓𝒆𝒒𝒖𝒊𝒓𝒆𝒅 = 𝟑. 𝟔𝟔𝟑 × 𝟐. 𝟐𝟏 = 𝟖. 𝟏𝒉𝒐𝒖𝒓𝒔
Therefore, you can charge an average single smartphone approximately 4 times for 8.1 hours on
the solar wheelbarrow when the sun is down.
Considering for other smaller phones with average capacity of 1500mAH
𝑻𝒐𝒕𝒂𝒍 𝒏𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝒄𝒉𝒂𝒓𝒈𝒆 =
𝟐𝟎𝟎𝟎𝟎 × 𝟑. 𝟕 𝟎. 𝟗𝟗
×
= 𝟗. 𝟕𝟔𝟖 𝒄𝒉𝒂𝒓𝒈𝒆
𝟓
𝟏𝟓𝟎𝟎
𝑫𝒖𝒓𝒂𝒕𝒊𝒐𝒏 = 𝟗. 𝟕𝟔𝟖 × 𝟏. 𝟒 = 𝟏𝟑. 𝟔𝒉𝒐𝒖𝒓𝒔
Therefore, you can charge an average ordinary phone approximately 10 times/13.6hours on the
solar wheelbarrow when the sun is down.
Figure 1 charge stages of lithium-ion
REFERENCES
[1] Vishwas N. Rahit Tiwari. (2020, May 20). Electronics geek, experimenting and innovating
https://www.quora.com/How-do-I-calculate-charging-time-of-mobile-phone-with-respect-tooutput-power-of-adapter
[2]
Mochammad N, Ahmad F. (2020, 0ctobe 17). “Application of solar powered wheelbarrow
for energy saving cooking process”. 4420page7.https://easychair.org/publications/preprint/cD4p
[3]
Hamdi Saipul 2014 Mengenal Lama Penyinaran Matahari Sebagai Salah Satu Parameter
klimatologi (Berita Dirgantara. Vol. 15 No. 1). (Lapan: Penelitian Pusat Sains dan Teknologi) pp.
7-16
[4]
Courtesy
of
Cadex
2021,
October
25.
“BU4-409:
https://batteryuniversity.com/article/bu-409-charging-lithium-ion
Charging
Lithium-ion.”