Are Solar Power Banks Better Than Regular Power Packs?
Power banks are portable battery packs that allow someone to charge their tablet or mobile phone, even without plugging them in a socket. Sometimes, it’s only when you desperately need to charge your phone during an emergency that you realize how helpful it is to have a power bank in your bag.
However, you don’t have to wait for emergencies to happen to have them with you. Power banks are easy to carry around since they don’t add much baggage weight. You’ll find several types of power packs in the market these days and solar power banks are one of them.
How Do Solar Power Banks Work?
It’s essential to note that solar energy is the most environmentally friendly and sustainable way to generate electricity. A solar power bank uses a small built-in solar panel for charging a rechargeable battery. This panel is a photovoltaic cell made of silicon and other semi-conductive materials.
Thin film solar cells are second-generation cells where the solar power producing photovoltaic material is coated as a film on a substrate such as glass or plastic material. These films are incredibly thin at just a few nanometers, which is 20 times thinner than regular crystalline silicon PV wafers.
This makes thin-film solar panels highly flexible and lightweight, allowing them to used in a wide range of applications. Cadmium telluride (CdTe) is the most common thin-film solar technology, while copper indium gallium diselenide (CIGS), and amorphous thin-film silicon (a-Si) are also used.
Thin film solar cells are particularly utilised in portable applications since they are extremely light compared to other PV technologies. They are used in hand-held devices such as calculators, mobile phones, emergency lights, power packs, etc. However, thin film solar cells are less efficient when compared to other PV technologies. A typical mono-crystalline silicon cell provides an efficiency of 24-27%, while a thin film solar cell provides a maximum of 17-22% efficiency.
While it loses in efficiency, it gains in lower costs and low-light situations. Thin-film has much better resistance to shading so performs very well in shaded locations such as tree-lined avenues, urban low-rise buildings. Similarly, thin film solar cells perform the best in consumer gadgets such as power packs that are always kept in shaded areas. Read more about thin film solar cells here.
Solar Power Banks vs. Regular Power Packs
A power pack contains a lithium-ion battery since lithium is a substance having a high tendency to lose free electrons. A lithium-ion battery has a high capacity of enduring numerous cycles of fast charging and discharging, which makes it an excellent tool for charging your electronics.
There are many kinds of power banks on offer today including regular power packs and solar power banks. If you’re looking for something that’s worth your money, which one should you choose? To help you decide, this post compares regular power packs and solar power banks based on several factors:
Portability And Sturdiness
Some regular power banks are as light and slim as your mobile phone. They’re portable, which means that they can get easily packed in any bag. Solar power banks also offer you the same portability as regular power packs.
Solar power banks and regular power packs are both built as sturdy as possible, too. You won’t be worrying about them getting damaged even if you have many items in your bag. Since most of their models have silicone rubber casings, they’re both safe from almost all forms of hard surface contact. Solar power banks and regular power packs are equal in this aspect.
Both solar power banks and regular power packs have a high-power capacity and can be used for charging your mobile phone numerous times. You’d surely agree that charging your gadget when traveling can get problematic, not unless your long-distance journey very often passes by coffee shops where free phone recharging is allowed. But, most travelers aren’t that lucky. Fortunately, power banks can help you get rid of the hassle. By bringing a solar power bank, you can relax and enjoy your adventure, knowing that you won’t always have to look out for charging opportunities. So solar power banks come out as the better choice over regular power packs since recharging the former is more convenient.
If you’re traveling for a longer time, your power pack will eventually need to be recharged so that it could stock power again. A regular power bank will require you to still plug it in a socket once it’s empty. On the other hand, a solar power pack only has to be taken out in the daylight for it to regain its power. When it comes to bringing you complete convenience when traveling, solar power banks clearly stand out.
Having the ability to restore the power of a power bank even without plugging it into a socket only means one thing – you’re saving a significant amount of electricity. Being environmentally friendly is the most important advantage of solar power banks over regular power packs.
Some models can even be charged by exposing them to fluorescent light. So you would be reducing your carbon footprint on Earth by not using electricity for charging your power bank. Without any effort, you’re contributing to the fight against climate change while enjoying your devices’ functionality. It’s clear that solar power packs have the edge when it comes to environmental friendliness.
Solar power banks and regular power packs may be equal in terms of portability. Still, solar power banks edge any other types of power packs when it comes to convenience when traveling, easy recharging, and environmental friendliness. Solar power cuts your electric bill and carbon footprint. So, are solar power banks better than regular power packs? Based on the factors above, this post thinks that’s certainly the case.
The Solar Mobile Charger and Powerbank is the first Developpa’s cornerstone project where a product will be taken from its conceptual stage (so when it is just an idea), through all the design and development process that you can see outlined below. This page will act as a sort of educational log book where I will write down and share the different work products, decisions and experiences of taking this product idea first from concept to prototype and then from prototype to mass production. This last stage will be mostly theoretical as I cannot actually produce 1000 of these units (unless you want to sponsor the project of course my dear reader :))
Because I am mostly an HW Engineer and FOCUS on electronics, most of the content will be aimed towards these areas. However, embedded software and enclosure design will also be part of the article.
Hopefully, you can use the structure here as a canvas for your next product design and you will enjoy the evolution of the project. I will do my best to keep on schedule, however, expect moments of quietness as I need to FOCUS on other aspects of the website and external duties.
With that said, let’s begin Developping!
Because this is not a product for commercial purposes, actual market research has not been made. However, it should be mention that if you intend to make a product for a profit, the first thing you should do is to determine if people will actually pay for it. This is a whole topic on its own and I did not study a related field, however, I will mention a few simple things you can do to determine if your product is sellable:
Look into existing products
Does your product already exist in a similar way? Do not reinvent the wheel. Look how well is selling a similar product, what people like about it and what they don’t. You can look into specialized websites reviews but these could be biased, otherwise, Amazon reviews should be a good starting point. By knowing what the other product is lacking then you can aim your design to address these issues, therefore, producing a possibly better sellable product. Another good thing about researching existing products is that it gives you a feel for the technical requirements your product should have. If it’s not a first generation product or unique, then other engineers have already gone through the design process and have selected components taking into account: technology limitations, costs and physical constraints such as size and weight.
Conduct user research
If you are like Steve Jobs you might want to skip this step. Find your target audience and ask them about what they think about your product. This can be done through interviews or polls. You will probably need to have some sort of incentive so people actually donate a bit of their time. Think of use cases as well. How will the user use this product? think in times of the day, location, number of users, etc. This could all give you valuable design requirements to be implemented.
If you are working for a client or company, you will have to deliver the project on an agreed date. Even if you are just making something for yourself for the sake of it and delivery time is not important, having a structured plan to follow can help you FOCUS and be more efficient as you can see the bigger picture and somehow have the road ahead slightly defined.
As in the previous section, Project Management is a topic of its own that apart from defining tasks and their delivery dates, also involves in assigning budgets to different parts of the projects (including the engineer’s wage), creating the team structure and roles, talking with suppliers to ensure components are delivered when required, contact point for client and many other tasks.
Because of the nature of this project, the project planning will mainly FOCUS in defining the main tasks of the development process and setting up some milestones such as the date when the PCB Gerber files should be sent to the manufacturer. I will also add delivery dates for the sub-tasks mainly for esthetical purposes as it will be very hard to keep on track with this level of granularity. Here is the main difference between an example project such as this with a real project where you have stakeholders that are expecting a product to be delivered on time. So if you are working on a project for a client I encourage you to try to stick to the deadlines written initially and give them some overhead. Humans are very bad at predicting how long they will take for a task and sure as the sunrise you will encounter problems along the way which will delay your original timing, as said in a previous article by Mario: Underpromise and Overdeliver.
Tools for Project Planning/Management
The classical project management tool is the Gantt Chart which is very good to visualize parallel tasks of the project. To make a Gantt Chart you can use Microsoft Project or download the free template I am using for Google Sheets in the Resources Downloads section:
Also, if you want to micromanage a team, I highly recommend using a Trello to assign tasks with time frames, add bullet points, images, link it to Google Drive folders and other interesting functionalities.
For the Solar Mobile Charger and Powerbank project, I have used the Gantt Charte Template where I have assigned with pretty much the same headings as this articles plus some sub-tasks. I am also using a To-Do list (Any.Do) for my daily tasks as I don’t want to put these, neither they are required in the Gantt Chart. I have created so far only one milestone for the 15th of July, where I should send the PCB Gerber files to a manufacturer for production and assembly, let’s see how things go
Note that, as this page, the content on the Gant Chart will also be changing with time.
_Requirements and Specifications
What does a practical hands-on engineer or maker hate the most? I would say spending time writing documentation instead of using that time for designing stuff. Usually, when an engineer already has the function of the device clear, he/she jumps straight into the design: buys an Arduino, programs it and makes the magic happens. And this is great, nothing better than having an early proof of concept of the product and show the stakeholders that you can make it. The issue with this approach manifests if, after the proof of concept stage, the engineer starts picking up components and designing the schematic without first having formalized the functions, behaviour, operating parameters and expected performance of the device.
When this happens, it is very likely that at later stages, an expected function will not perform properly because this was not exclusively specified. Suppose that you are building up an electric car (ambitious project right?) and you have to design a battery management system that senses current so you can determine the state of charge of the battery by counting coulombs. You design your current measurement circuit and chose good components without doing a WCA and really looking into the actual accuracy you can achieve with your circuit. Later you found out that the time the vehicle can last without charging is less than expected, and you figure, well probably the battery wasn’t sized properly, the motor is not as efficient as they say and so on. You never thought in checking the accuracy of the current measurement circuit, after all, they just asked you to design it no one SPECIFIED THE ACCURACY OF THE MEASUREMENT. And that could be, exactly the root cause of the problem because the required accuracy wasn’t specified from the beginning, the designed circuit didn’t take this into account and turns out that your coulomb count is inaccurate and is showing the wrong charge level of the battery.
After this example, you can hopefully understand the importance of having an agreed set of requirements and specifications before starting the detailed design It will save you time, money and it gives you a design goal, you can now design your circuit with a tangible and measurable result in mind.
Solar Panel Vs Power Bank For Backpacking
Thinking about replacing your power bank with a solar panel for backpacking? In this article, we’ll unravel the optimal situations for solar panels.
People nowadays need lots of power to charge their headlamp, hiking watch, camera, smartphone, satellite messenger, portable speaker, vibrator, and so on.
Wouldn’t it be great if we could do that with a solar panel instead of a power bank?
It’s a cool idea, but is a solar panel worth it?
That’s what we’ll discuss in this article.
The Difference Between Power Banks, Solar Panels And Solar Chargers
To avoid any confusion, I want to first make it clear what I’m writing about.
Solar chargers are solar panels with a built-in power bank (read: battery).
So solar panels don’t have a battery. They cannot store energy. So in order for them to work, you need to connect a standalone power bank or whatever electronic device you want to charge.
Solar panels, solar chargers and power banks are very similar: all three can be sources of energy. Yet the slight difference in exactly how they power you will have a huge impact on which charger is best for you.
However, in this article I’ll only discuss the debate of solar panels versus power banks.
What Factors Affect Your Decision?
I think most backpackers are better off with a power bank, as one of 10,000mAh is probably enough to keep your electronics alive between town stops. I usually last a week with such a power bank, and I belong to Generation Z (aka the phone-addicted generation).
Even if I need more power, I’ll probably just take an extra power bank with me because two of them are still lighter than one solar panel. A 10,000 mAh power bank weighs about 7 oz. A solar panel is something like 16 oz.
And power banks are not dependent on sun exposure the way solar panels are. That’s a big advantage.
That said, maybe you are the exception. Maybe a solar panel is a better fit for you.
Your energy consumption: If you need to carry a lot of power banks in the backcountry because you’re using extremely high amounts of energy, a solar panel may be a lighter and cheaper choice.
Time available for charging: The charging speed of solar panels depends on panel size, sun exposure, and the angle of the panel to the sun. Deserts are perfect for solar panels because there’s barely any shade. Are you going backpacking in a rainy area or dense rainforest? Then forget the solar panel and take a power bank with you.
Time between town stops: If the time between towns (and therefore recharging opportunities) is measured in weeks rather than days, then a solar panel may be your only option. You don’t want to carry the weight of five power banks, do you?
Town charge reliability: Say you’re going backpacking in a third world country where electricity is unreliable and you’re not sure if you can charge your power bank in town. In that case, it may be better to bring a solar panel.
Hiking speed ( your backpacking budget): If you’re like me and avoid the civilized world as much as possible while backpacking, keep in mind that charging a power bank can take all night, depending on its size. That means you may have to spend the night in some sort of hotel, which adds to the cost of your trip. A solar panel can be hung on your backpack and charge your devices while hiking.
If you’re a slow hiker and don’t care about the miles, then a little extra weight is not important. In that case, you can choose to bring a solar panel.
Weight importance: A pound or two more, who cares? If you think of it that way, you might as well bring a solar panel for fun. Just don’t overdo it! A backpack too heavy is dangerous.
It’s a cool idea: not relying on electrical outlets and just letting the sun do the work.
But does it make sense for you to go solar? Shade and weather are the main factors to consider. But also think about your hiking style and recharge opportunities/reliability in town.
If you know the limits of solar panels and what you’ll encounter on the trail, I’m sure you’ll make the right decision!
Storm De Beul
Born in the midst of a storm and raised by new-age hippies in a green corner of Belgium, it’s no surprise that Storm became the backpacker of the family. Turns out he loves to write too! And his English isn’t that bad either! Let’s start a blog then, at least I’ll be doing something useful with my time, he thought.
Solar Power Bank With Salvaged 18650
About: I’m a graduate of Aircraft Engineering Technology (Hons) in Mechanical. I am passionate about energy, electric vehicles, gadgets, tools. My projects basically reflects my needs. About amorarun »
I had this old iPhone 3G, its battery life was terrible and I didn’t had enough money (at that time) to change the phone or the battery or to buy a power bank. I had to charge the phone at least 2 times a day. so that I can attend few calls. But I had few of the things needed to built a power bank and this is what I have done to keep it alive. The cost of making power bank alone was just around US3 or so.
Oh forgot to mention that I added solar panel for charging under sun too.
Step 1: Stuffs You Need
This was made using most materials that was on hand including solar panels and other misc items, only had to buy the Lithium battery charge controller and the step-up module to keep the power bank small. The materials used in this project are as follows,
Items I had on hand:1. 18650 cells extracted from old laptop battery, if you want to know how click here.
Scrap metal tabs salvaged from the laptop battery.
Small slide switch or any other type is fine.
Things that are bought:1. Lithium battery charger board with micro USB. I bought for 0.99 from ebay link below, www.ebay.com.my/itm/5V-Micro-USB-1A-18650-Lithium-.
5v 1A output Boost Step-up module, bought from the same seller for 0.99,www.ebay.com.my/itm/Mini-PFM-Control-DC-DC-.
Utility Knife or side cutter
Helping Hand (useful but not necessary)
Note: I forgot to add a 18650 protection circuit, since the battery extracted from laptop battery does not have them. So if you are using a battery without protection circuit make sure you get one, to avoid over-discharge (this will damage the battery).
Step 2: Wiring Connection
The connection is pretty straight forward and is shown in the diagram above. For those who want to know which wire goes where continue reading others skip to the next step.
First lets start from the Solar panel,
1.Solar panel has a diode on the positive side to prevent the flow of current from the battery to the cell. 2. The Positive and Negative of the solar panel is connected to the N and N- of the charge controller respectively.
The BAT and BAT- is connected to the Lithium Battery’s Positive and Negative Respectively.
The Battery positive/ BAT is connected to a switch and the other pin of the switch is connected to the positive of the Set-up module.
The BAT-/ Battery negative is connected to the Set-up module’s negative.
A resistor of value 47 ohm is soldered on the data pins of the USB output, which helps to charge iPhone phones since they need some signal to activate charging, without this iPhones wouldn’t charge.
You can add any number of solar panels in parallel to increase the current and thereby charging faster.
The micro USB on the charge controller helps to charge the battery by USB outlets.
Step 3: Assembly and Testing
It is self explanatory with the pics. I will try to explain what was done as briefly as possible.1. First the metal tabs were soldered (that was salvaged from laptop battery) in the middle of a piece of wire. these will act as the lithium battery contacts, which enables the battery to be removed if needed. pics 1 and 2
Then made a hole for the wire from solar panel to go into the 18650 box and inserted the two wires(red and black) into the box. pic 3
(In pic 4 I made a mistake by soldering the wire from the tabs to the solar panel, perhaps I was physically present and mentally somewhere else.lol. So it was de-soldered and the wire was cut on one side from the battery tabs.)
Hot glued the metal tabs in place after checking the fit with the battery.pic 5
Placed the charge controller and step-up module inside the box and marked the places to be cut out. pics 6 and 7
Cut out the marked area using side cutters (it was easy to do with it but it did made a crack on the plastic, so use utility knife).
After checking the fit, soldered the solar panel wires to the charge controller, battery tab wires to the charge controller, step-up module to the battery with the switch and the 47 ohm resistor to the output USB. pics 8,9 and 10
Inserted the battery to test the circuit, by turning on the switch to see if the step-up module powers up. pics 11,12
To make the solar panel easy to face the sun, decided to add Velcro to the bottom of the box and solar panel. pic 13, 14 15 and 16.
Soldered the solar panel and tested it out the window to see if the charge controller powers up and charges the battery. pic 17.
Added another solar panel parallel to the existing on to decrease the charging time. pic 21, 22
Note: I haven’t tested it completely, for example how long it takes to charge? I will update those details once I tested it.
Step 4: Modification/ Upgrade
After the built I felt that the positioning of the circuit board interfered with opening and closing of the box and the circuits were not stable (it moved around a lot). Therefore I transferred the contents to another box.
With the soldered Solar panel it was difficult to carry it in therefore I made them removable by using male and female header pins to quickly connect and disconnect.
The best thing about this power bank is it is versatile to charge using USB output from computer or wall charger or using solar panel, plus you can increase the capacity simply by replacing with a higher capacity battery.
Note: You can use this to charge any phone however charging time may vary depending upon the capacity of the battery and many other factors. You can also attach LEDs to use this power bank as a portable battery as well.
Note: I forgot to add a 18650 protection circuit, since the battery extracted from laptop battery does not have them. So if you are using a battery without protection circuit make sure you get one, to avoid over-discharge (this will damage the battery). Thanks to instructable member brzi420 for pointing it out.
Any suggestions and Комментарии и мнения владельцев are welcome.
And kindly vote for it, if you like it.
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6 Комментарии и мнения владельцев
the micro USB you have linked to is different to the one you have used as the one in the link has a protection circuit aswell as the charge circuit, it connects to the battery and then the board can be wired up to whatever you want the single 18650 to connect to
Well thats great, I bought mine about a year ago and did not have any protection circuit, so this one is much better thanks for pointing it out.I am glad that you found this useful.Cheers
definitely useful, inspired me to do this (see pics below) but as I only had the charge circuit and 5v boost up available I used a battery with built in protection but will be doing another couple with the batteries I found in my mum’s dead laptop battery which had a damaged contacts so lucky me lol
Nice built. Post your other built pics too when you are done. Yeah better to recycle those perfect cells than throw them away.
glad I read this as was planning on just making it didn’t even think of a protection circuit lol
Where can I buy a battery and the wiring for a 2 USB waterproof I have the boards just need wiring info
Hi. Can you make a DIY 5 18650 battery solar power bank with dual USB output (2a and 1a). I’m confused with what parts should I prepare. Thank you.
You can use power bank circuit like this one ( http://s.click.aliexpress.com/e/e6AYBqf ) and add 18650 cells in parallel. Cauition: Before adding cells in parallel check that the voltage level of all the cells should be same.
DC to DC converter has a max 600mA output. Most modern Android phones need at least 700mA to charge. This will not work
You can use the 2A version of the circuit which has current capacity of 2 Amps. You can see here: http://s.click.aliexpress.com/e/72NN76y
hey there. amorarun. so. can i know how much time will it take to completely charge a 5000/10000 mAH power bank ?
Bro plzz tell me.I have 4 battries each battery have 4.8V DC power.Can I use my 4 batteries at a time.Is there any problem for my circuit?? reply me fast frnds
You can do that but the charging circuit mentioned in this Instructables is designed to charge only one battery. The problem with using more than one battery in parallel with this circuit is that it can’t balance the cells. This can lead to uneven charge and might damage the cells in the long run. Do Google about charging lithium ion batteries and you will get loads of info.
I’m not much of an expert about lithium batteries, I’m still learning. I could be wrong.
When the cells are connected in parallel, they are always balanced, because the voltage for all points that are connected is the same.
The only difference when connecting more cells in parallel is that there is more capacity to charge, so you either need a larger charging current, or it would take longer to fully charge the battery pack. It is true that the correct charging current will extend your battery life, but it’s far from critical. Also, I don’t even expect that you will achieve the ideal charging current for a single 18650 cell from a small solar cell. BTW always better to have a smaller than ideal charging current than a current that’s too large. A low charging current can decrease the battery life a bit, but too high of a charging current might end the battery life instantly, with fire. 🙂
When you want a higher voltage power bank and start connecting the battery cells in series, that’s when you need to start thinking about balancing the voltages.
Anyways, just trying to educate (maybe you already learned this as the I’ble is already a year old). I really like your project and I’ll soon be making my own so that I can charge up my digital camera’s battery from the power bank after a day of hiking in the sun.