Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

solar powered mobile phone charger

Status
Not open for further replies.

nic_marsa11

New Member
A few of you helped me out before in solar powering a quartz clock, which works now! exciting! thanks very much.

Anyway, next project. I've seen lots of tutorials for a solar powered mobile phone charger online however none of them involve capacitor or rechargeable battery. Charging a phone on the go is ok, but what I'd like is a solar cell that would charge a battery or capacitor. I could then run or charge my phone of the battery/capacitor rather than off the solar cell, which would only work during the day.

My phone's battery is a 3.7V Li-Ion battery, at 880mAh and 3.26Wh. I'm going to buy a solar cell, schottky diode and super capacitor as before, and connect the phone across the capacitor. However, despite researching theory, I'm still stuck on what values each component needs to be

Any help or links to components would be really appreciated,

thanks
Nic
 
Super caps aren't going to really hold enough power, not if you want it to be reasonably priced. You're going to want to go the battery pack route if you want any kind of serious capacity without breaking the bank. Super caps are generally useless if you don't have a buck/boost converter associated with them because the amount of extractable power compared to the total energy they store is horribly low when the voltage regulation levels have to pretty precise.
 
Super caps aren't going to really hold enough power, not if you want it to be reasonably priced. You're going to want to go the battery pack route if you want any kind of serious capacity without breaking the bank. Super caps are generally useless if you don't have a buck/boost converter associated with them because the amount of extractable power compared to the total energy they store is horribly low when the voltage regulation levels have to pretty precise.

Okey doke, how many of what batteries do you suggest? And what's a buck/boost converter? I'm planning to use this on hiking so if weight's an issue i'll be ready to pay more for the super capacitor.
 
If you just want the phone to charge in the sun why would you want to use supercaps or a battery? A super cap won't do much of anything useful as they can't by themselves maintain a voltage, if the charger in your phone is set to turn off at 4.0 volts the bulk majority of the charge in a super cap will never be used because between 4.0 volts and 0 volts there is a huge amount of energy stored that the phone can never tap, it will at best buffer clouds passing or passing under a tree, and most of it's potential will never be used, a battery pack could be used but again it's not really a plug and play thing, not used optimally at least, you'd be better off buying a commercial device that has all the circuitry required to properly do this.

I do question the need for this device in the first place, how long are you going to be out? I have an identical battery in my cell phone and I only have to charge it once every 3 days or so, and that's with moderate texting and minimal voice. If this is for safety there is a simpler sollution; what really drains a cell phone's batteries is when you're in a remote location with little signal, it will kill the battery trying to hunt down a tower connection, if the phone is off the battery will be preserved for weeks. Only turn the phone on when you need it, to check for voice mails or what not once per day if you can get a signal. If you're going to be out for more than a couple weeks bring a second battery fully charged and vacuum packed in a plastic bag. A cell phone battery will maintain a useful charge for months not connected to anything.

I've had problems when visiting my Grandmother because she lives in a mountainous region of PA, and her house happens to be an RF dead zone. Any cell phone brought to her house will have a dead battery in less than two hours from trying to find a tower, which it can occasionally connect to JUST long enough for it to want to keep trying.
 
ok thanks for the personal angle, I appreciate the advice. However, I'm actually doing this project more to get a better understanding of solar cells and wiring. I'll use the practise from this to make other projects. I also camp and hike a lot. If i can create this system it'll give me more flexibility on my phone. If not, i'll just keep the phone turned of as you say.

Anyway, back on topic. So there's no practical system that will store energy, which i can connect my phone to at any time (not just daytime)? I can only realistically charge directly from sunlight? What's the commercial device you're talking about?

Cheers
Nic
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top