Solar usb iPhone 4S charger, HELP! STUCK! Noob!!!

Discussion in 'The Projects Forum' started by Pkunze123, Mar 24, 2014.

  1. Pkunze123

    Thread Starter New Member

    Mar 23, 2014
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    0
    I have been working on a solar powered iphone charger like you see on YouTube and instructables all over the place. Only problem for me is that I have used multiple types of chargers and still have no luck. Getting the thing to work!!! I need some help trouble shooting!

    Please check out one of the videos here:
    http://youtu.be/x1wl092ljXI

    And the instructables here:
    http://m.instructables.com/id/Double-Capacity-MintyBoost-with-4-AA-Battery-Holde/?ALLSTEPS

    Here's what's happened so far:

    1) tried chargers for wall outlets, nothing
    2) tried charger for car outlets, nothing
    3) tried the same charger shown in multiple online instruction videos, Success!!!

    But wait... iPhone 4S says charging, but battery depletes like normal, even when powered off but still plugged in to "charger".

    So here's where my noobie mistakes began, I think...

    According to most videos and instructables, the charger from EBay uses 2AA batteries so the solar panel and rechargeable batteries in a battery holder are wired together to the circuit board of the chargers usb hub.

    "Easy enough to modify this" says I!

    I go out and buy a 4AA battery holder and wire it up as the instructions say. But I guess that won't work for some unknown reason... Problem 1

    Also, I still want to use 4 batteries for multiple charges and more power while camping. I think this means I need to separate the battery pack into 2 separate "cells" and wire them both to the terminals of the circuit board?... Problem 2
    (I know how to do that, I just want to know if doing so will give me the proper amount of power but more room for multiple charges? Problem 2.5)

    Really, I'm wondering if creating and wiring two separate 2AA "cells" to the terminals will fix everything and make this project work properly and give multiple charges?!?!? Problem 3

    What does it do to the power output of the batteries if they are separated into 2cells instead of wires in a series?

    How much power does an iPhone 4S need to charge?

    If this charger works, unmodified... Then why does it not work with the solar panel and 4AA batteries wired to its terminals?

    These three problems and these three questions I need answered please!

    Now I really need answers to this post to be non-sarcastic or smart mouthed because I am seriously trying to get into building electronics and don't want a "just buy it on eBay" or "why even try" the answer to both of those is that this is simply a project I want to fully understand in order to move on to bigger and better projects with a sufficient knowledge of what I am doing!
    With that being said I also need the answers to be in an almost kindergarten- like set of terms a noob like me can understand.

    Thanks so much in advance!!!
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,085
    3,024
    This is a big part of the problem for any solar charger. A phone needs a lot of juice, and that means you need a large solar panel to get the job done in a reasonable amount of time.

    Another problem with smartphone charging is that most are, well, smart. They require specific properties of the charger in order to initiate proper charging.

    I had trouble following your other questions. Could you provide more detail about what you did and what your questions are?
     
  3. burger2227

    Member

    Feb 3, 2014
    190
    24
    Most cell phones use 3.7 volt lithium batteries. NiMH rechargeable batteries are 1.25 volts so 3 in series would be needed to match the voltage. Adding 3 more in series parallel would increase the current available.

    Lithium batteries should not be discharged to less than 2 volts and they also require protection circuits when used in battery packs where more than one lithium is used in series. Each lithium cell needs to be monitored separately during charge and discharge with special circuitry.

    Fortunately the cell phone already has a protection circuit for charging built in. To charge it up quickly you should be able to send at least 100 ma of current to it through another battery or solar panel. Less current will take more time or will not charge it up at all.
     
  4. Pkunze123

    Thread Starter New Member

    Mar 23, 2014
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    0
    Update! I was able to successfully speedster my 4 battery holder into two separate banks, but now there is another problem... Each individual bank with fresh household batteries will start charging the phone! BUT, wiring the two "cells" in parallel doesn't work! Even with fresh household batteries the phone says charging but starts losing power while charging?!?!
    Is it possible that too much volts or amps can prevent the chargers circuit board from working?
    Also, can the phone send power back through the device to the rechargeable batteries?
     
  5. burger2227

    Member

    Feb 3, 2014
    190
    24
    2 cells in parallel? What kinds of voltage are you getting before connecting them to the phone?
     
  6. Pkunze123

    Thread Starter New Member

    Mar 23, 2014
    5
    0
    2.9 volts 2850 mAh each cell

    Which means on parallel I get 2.9 V and 5700 mAh
     
  7. burger2227

    Member

    Feb 3, 2014
    190
    24
    Don't believe those milliamp hours! If you get over 1000 MAH in use, you got good ones. China is flooding the market with all kinds of absurd MAH. They don't want them back either. I know because I bought a few AAA and none of them made it to 400, let alone 1200.

    Stick another battery in series and see what happens. The phone is protected and USB chargers give them 5 volts.
     
  8. Pkunze123

    Thread Starter New Member

    Mar 23, 2014
    5
    0
    Ironically. It did not make a difference having more batteries in the series. Whether I had three or six it still would not charge if there were more than two batteries in a series. However, the matter what the real mAh are, I still get one good charge and can refill the charge from about 50 to 80% on one good charge of the rechargeable batteries for one good set of household batteries.

    Any chance that the circuit board from the USB charger simply can't handle being hooked up to more than two batteries not matter what the configuration is?
     
  9. burger2227

    Member

    Feb 3, 2014
    190
    24
    Did you add diodes to the positive end of the 2 pairs of batteries in parallel like the Instructable? Does the charger board produce a higher voltage to the USB port? Some charger boards even boost voltages for a USB voltage 5 volt output.

    Not sure what could keep the phone from charging. The phone regulates the charge rate so all it really needs is 5 volts and it does all of the work. More current in parallel should not matter. It will only use what it wants anyhow.
     
  10. Austin Clark

    Member

    Dec 28, 2011
    409
    44
    You should draw out a schematic of exactly what you have, and what you have tried. If I had to guess, I'd say there's an issue with the batteries you're using. They're likely dropping voltage under the heavy charging load, and going well under 5V. In my experience, to charge a phone you need to maintain at least a solid 5V under a 500mA load. Even dropping to 4.9V will sometimes cause my picky iTouch to refuse to charge. A linear regulator might not work, if you're using one. I tried once, and found that the regulator tried to regulate at 4.9V-ish, under load it dropped very easily to 4.8V, which failed to initiate a charge on my pickier devices.

    Also, the resistor divider you use to supply voltage to your data pins (to initiate charging on certain smart phones/devices) is pretty sensitive. You need to use very close values for these, and/or try different configurations you find online and find what works best for you.
     
  11. Pkunze123

    Thread Starter New Member

    Mar 23, 2014
    5
    0
    So now im stuck where I have Isolated each cell with its own solar panel and two AA NiMH batteries... unfortunately, even with full charge on the bateries it STILL wont charge the iphone!!! its a 4S but im still not sure what else is going on here...

    ill upload some photos if there is anyone who can help me troubleshoot
     
  12. wayneh

    Expert

    Sep 9, 2010
    12,085
    3,024
    Better than a photo - which is better than nothing - would be a schematic or diagram of what you have done. Your descriptions may make sense to you, but I cannot follow them.

    An iPhone needs specific voltages on the data pins in order to initiate proper charging. Simply supplying power-only will not do the job.
     
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