Jeremy W. Langston

Personal Website

Battery-powered USB Phone Charger

I was getting ready for a long train ride from KY to DC and found out there aren’t any AC outlets for coach seats!  A 15hr ride isn’t too bad when you have a smart-phone; then again, the stock battery on an HTC Incredible will last only about 3hrs of heavy usage.  Not good.  I wanted a way to be able to use it for, well, 15hrs.  So, using some easy-to-find parts I made an extended battery that will charge the phone via USB.  I also wanted the extended battery to be rechargeable.  So, I need to be able to have access to the battery contacts; maybe later I will add something fancier, but for now the battery disconnects from the USB circuitry.  Here’s my finished product, and how to make it.

IMAG0075

I bought a battery from the local Home Depot for $20 (look in the outdoor lighting aisle).  It is 6V and provides 6.5AH.  You can get it cheaper at places like batterymart.com, but I was in a hurry and the shipping on seal-lead acid batteries is not cheap.  The higher the amp-hours (6.5AH in this case), the longer you will be able to run your USB device.

IMAG0064

Now for the voltage – USB uses 5V DC.  I needed to drop the voltage from 6V to 5V, preferably without too much loss.  There are three main options:  voltage divider using resistors, non-switching regulator, and a switching regulator.  In the case of the voltage divider, the resistors basically turn the extra voltage into heat, and they would need to be rated for higher power than the typical $0.01 resistors.  Switching regulators, or DC-to-DC converters, are much higher efficiency, but are more costly.  Also, I couldn’t find one that would work at Radio Shack, so I went with a non-switching regulator:  the 7805.

IMAG0066

The 7805 regulator will take voltages higher than 5V and hold them at 5V, also allowing up to 1A of current.  While that’s much more than is needed, it gives a nice buffer.  A regulator has three legs:  1) input, 2) ground,  and 3) output, where the ground leg is shared between the input and output.  The input comes from the positive side of the battery, the output goes to the 5V pin on a USB connector, and the negative side of the battery along with the GND pin on a USB connector both connect to the ground.  Since the 7805 drops the difference in voltage by heat, adding a heatsink to the regulator might be needed, depending on how much power your device will draw.

IMAG0063IMAG0068

To connect USB devices, I need an adapter that would allow me to plug in a standard USB cable, like the one in your computer.  I happened to have an old PS2/USB adapter from an old mouse.  It hasn’t been used, ever, so I cut it up (the green thing above).  You could use something else, like a USB extension cable which already has wires to solder to.  USB connectors have 4 pins:  1) 5V, 2) Data+, 3) Data-, and 4) GND.  Use some wire to solder the connections (USB 5V -> 7805 Output), (USB GND  and Battery negative -> 7805 Ground), and (Battery positive -> 7805 Input).  Make sure to protect the solder points with some heatshrink or risk shorting, melting, and other bad things.  To connect the wires to the battery terminals, I used spade connectors.  Also, leave the terminals pointing up for reasons I’ll point out soon.

IMAG0067IMAG0069

Once the soldering is done, connect the battery and use a multimeter to check the output on the USB connector (voltage across pin 1 and pin 4 should be +5VDC).  Then you can freely connect a USB device and you’re set.  You could stop here and be done.  Since I wanted this for travel and didn’t want exposed wires, I took it a step further:  enter hot glue.

Clean the top of the battery and add a layer of lubricant (e.g. WD-40) to keep the glue from sticking to the battery.  We want the circuitry to be detachable so that we can recharge the 6V battery using a trickle charger/car charger.  This is why I left the battery terminals sticking up – so that I can freely pull the circuit away from the battery.  I used about 10 – 15 sticks of hot glue used on a mini gun, just to make sure that everything would hold together.  This is the most time-consuming part.  It doesn’t take a lot of thought to do this.  Just fill in all the holes, keeping the USB port accessible.  You also want to keep the heatsink partially uncovered so that it passing air can pull away the heat given off by the 7805 regulator.  You could spend a lot of time getting this pretty by squaring up the sides and making it colored, but this was a last minute project for me.  Hopefully you will get some good use out of this – I know I will.  I hope they don’t kick me off the train thinking it’s a bomb.

IMAG0070IMAG0072

IMAG0077IMAG0078

IMAG0073

50 Comments

  1. We couldn’t be happier with the outcome of this website. Thank you for such a great contribution! direkturtoto

  2. Finding good Nursing Dissertation Topics is always a challenge, but thanks to this service, I was able to select a topic that was not only interesting but also feasible within my academic schedule. The service was professional, timely, and very affordable for a student like me. Their writers really know the UK nursing curriculum, and they tailored the dissertation according to my preferences and university guidelines. I received excellent feedback from my professor, which boosted my confidence. I’m so glad I found this service when I did. Highly recommend it!

  3. If you are seeking a girl for adult entertainment, sexual service, or a kinky massage.

  4. Please come in to hire our hot and exotic models.

  5. Then, you will realize that they are gorgeous, bright, well-mannered, and educated.

  6. xnxx it is truly inspiring and educational!

  7. This is such a clever and practical solution for long trips without access to power outlets! Your detailed explanation and step-by-step guide make it easy to follow along. It’s impressive how you managed to create a rechargeable extended battery using readily available parts. I’m sure this will be incredibly useful for anyone facing similar challenges. Great job!

  8. The important thing you need to keep in mind is that giving you a Dehradun escort and call girls in Haridwar as a sex professional is absolutely common.

  9. iconwin it is truly inspiring and educational!

  10. At Instant Assignment Help uk,we offer students in all subjects assignment help and assignment writing services. Purchase assignments at Assignment Helper and receive online assignment support at the best price.

  11. At Instant Assignment Help
    , we offer students in all subjects assignment help and assignment writing services. Purchase assignments at Assignment Helper and receive online assignment support at the best price.

  12. Game online Indonesia dengan berbagai pilihan mode permainan yang bisa kamu nikmati. Direkturtoto

  13. I’ve been struggling with statistics assignments, especially when interpreting data and applying complex formulas. It’s great to know that there are Statistics Assignment Help services out there to provide expert guidance. I often find myself overwhelmed with deadlines and would love to get a little extra support. This article has really opened my eyes to the possibility of reaching out for professional assistance, and I’ll definitely look into it more. Thanks for shedding light on this valuable resource!

  14. HNC opens up a flexible variety of subject areas to the scholars to choose their preferred career pavement. This characteristic assists them in polishing their talents and competence in conformity with contemporaneous job requirements. It provides a wide range of academic disciplines such as humanities, computing, business management, engineering, law, healthcare, accounting, graphic designing, finance, construction, etc. The HNC assignment is challenging for students. So it requires students to get HNC Assignment Help from experts.

  15. Prior to beginning your diploma assignment, you require to become agreed with the exclusive necessities your assignment has. Having such information will agree to you to avoid needless errors and will assist to systematize a paper completely. This is more significant to acquiring Diploma Assignment Help to complete their assignments.

  16. As a psychology student and teacher, I’ve always found managing assignments overwhelming, especially when deadlines pile up. Fortunately, seeking help from an assignment helper has been a game-changer. These services not only assist in organizing my workload but also ensure that I get a clearer understanding of complex concepts. For example, when working on a cognitive psychology paper, I utilized Psychology Assignment Help to refine my research methodology and improve my analysis. This kind of support has saved me countless hours and significantly boosted the quality of my assignments, leading to better grades.

  17. As a psychology student and teacher, I’ve always found managing assignments overwhelming, especially when deadlines pile up. Fortunately, seeking help from an assignment helper has been a game-changer. These services not only assist in organizing my workload but also ensure that I get a clearer understanding of complex concepts. For example, when working on a cognitive psychology paper, I utilized Psychology Assignment Help to refine my research methodology and improve my analysis.

  18. Are you a scholar who is pursuing a specialization in Biostatistics and need professional help to prepare a mind-blowing assignment solution? Don’t be anxious! Meet the highly qualified and experienced Biostatistics Assignment Help tutors and receive authentic and quality papers for every academic project submission and attain excellent grades in your overall curriculum effectively and easily!

  19. Thanks for sharing this Informative article I work online to help students in their online management assignments help. Management Assignment writer was a lifesaver! The experts provided well-researched, high-quality work, and delivered it on time. Their support made a huge difference in my academic performance. Highly recommend

  20. Ctdude Directory India, the premier provider of professional call girl services in India.

  21. Fantastic blog! I’m glad to know you learned something worthwhile.Looking for an essay helper? Get personalized support from experienced writers to improve your essays. Whether it’s brainstorming, editing, or crafting your paper from scratch, our reliable service ensures top-quality, original work. Simplify your academic writing process with expert guidance tailored to your needs.

  22. Hindi songs are known for their rich melodies, expressive lyrics, and emotional depth. From soulful ballads to energetic dance tracks, they span various genres, reflecting the diverse culture of India. Whether it’s Bollywood soundtracks or independent music, Hindi songs have a timeless appeal that connects deeply with listeners, making them a beloved part of India’s musical heritage.

  23. Their escorts are not only stunning but also intelligent and well-spoken, making every encounter enjoyable. Dehradun Escorts Service Enjoy top-notch service and privacy when you choose Dehradun Escorts Service.”

  24. Fantastic post! I appreciate the depth of your research and the clarity in your explanation. toto slot

  25. Your blog post is fantastic! I love how you break down complex concepts into easily digestible information. It’s refreshing to see such clarity and depth in your writing. For anyone struggling with business assignments, I recommend exploring Global Assignment Help Australia for expert assistance. They provide excellent Business Assignment Help that can really make a difference in understanding and completing assignments on time.

  26. Thank you so much! Your support means the world to me

  27. The Chicago Bulls jacket collection perfectly captures the spirit of one of the NBA’s most iconic teams. The timeless red, black, and white colors are a nod to the team’s rich history and their unforgettable run during the 90s.

  28. I really like this content. Thanks for sharing such informative information.

  29. Choosing Furnish My Place LLC for my flooring needs was the best decision. The installation was smooth, and the final look is stunning! Highly recommend their services for anyone seeking both style and durability. https://furnishmyplace.com/flooring/lvp/charlotte-nc/

  30. Choosing Furnish My Place LLC for my flooring needs was the best decision. The installation was smooth, and the final look is stunning! Highly recommend their services for anyone seeking both style and durability.

  31. You made a few good points there. Used to do searching on the issue as well as identified practically all individuals goes together with along with your blog.

  32. Daftar di iconwin dapat bonus 200%

  33. Thank you for sharing these insights. Your posts are always so thorough. Hokqbet88

  34. A dissertation proposal is an important step toward completing a dissertation, particularly at the graduate and doctorate levels. This document describes the research you want to conduct, including its significance, objectives, methodology, and possible contribution to the field.

  35. It is really a nice and helpful piece of information. I’m satisfied that you simply shared this helpful info with us.

  36. Excellent aspects as well as fine points are imparted in this condensed content. Waiting more posts such as this one.

  37. Good assortments. Nice to read essay about fashion. Continue posting new blogs.h as this one.

  38. Boost your academic performance with our expert Dissertation Statistics Help services. Get tailored solutions for all marketing topics, ensuring well-researched and top-quality content. Plus, use our Free Grammar Checker UK to perfect your writing, eliminate errors, and present flawless assignments. Achieve higher grades with comprehensive support and error-free marketing papers, every time!

  39. At Growthleadersconsulting, Increasing sales is the most critical task for any small business and we at Digital Growth Partner, will help you in generating the right volume of quality leads using the most cost efficient channels that will power your business.

    business consultants agency in noida

  40. You have shared very informative article with us. Thanks for sharing it.
    For more information about Betpro Account

  41. slot online gacor With a focus on excellence, this website combines visually appealing design with well-researched content, ensuring visitors get the best experience every time

  42. Great article, thanks for sharing, please visit our website and register now there are many attractive benefits for you

  43. Travelers can expect a first-class service with Delta Airlines NRT Terminal. The terminal, which is located in the South Wing of Terminal 1, has a number of dining options, a comfortable Sky Club lounge, and contemporary check-in amenities. Praising the staff’s multilingualism and quick service, travelers are guaranteed a hassle-free trip. Enjoy a pleasant airport experience with Delta, which offers free Wi-Fi and lots of shopping options. Delta Airlines NRT Terminal puts comfort and convenience first for all passengers, whether they are flying for business or pleasure.

  44. Very good information has been given, it helped us a lot and we are also sharing this information further Hanuman Chalisa PDF

  45. The author is very good, this is a very good article. I have read this article for the first time and I liked it. Hanuman Chalisa PDF

  46. I’d like to find out more? I’d like to find out
    more details.

  47. Hey There. I found your blog using msn. This is a really well written article. I will make sure to bookmark it and come back to read more of your useful info.

  48. You are the one who shares lots of useful information with everyone. I hope you will be continuing this. Thanks for sharing these Independent escorts in Goa kind of post.

  49. An aesthetically pleasing and functional design that’s a joy to explore! gaya4d

Leave a Reply

Your email address will not be published.

© 2024 Jeremy W. Langston

Theme by Anders NorenUp ↑