Charging cell phone?

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Rollin
Rollin Registered Users Posts: 2
in Solar Beginners Corner #1
If I were to buy a 5 or 10 watt solar panel would I be able to directly charge my cell phone or does the phone require a 12v dc or 120v ac power source? Also I would like to be able to charge some AA rechargeable batters off of the same panel with a battery charger... Can I do this directly or would I need to go through an inverter ?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
    #2
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    Re: Charging cell phone?

    I just got one of these Goal Zero 7 watt solar/AAA/AA charger kits (similar) from Costco for ~$100... I charged my Droid X smart phone with one and it worked fine.

    -Bill

    PS: One thing to remember is that these need to be left in full sun for (probably) a few hours (at least) to fully recharge batteries/cell phones. So--either it needs to be in a secure place or somebody has to watch it while charging so it does not grow legs.
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    #3
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    Re: Charging cell phone?

    We have never found a good answer to that. There are quite a few adaptors for battery to USB and other 5 volt to 9 volt gadgets, but so far we have found none that will work directly from a solar panel. The problem is that a "12 volt" solar panel can put out as much as 20-24 volts open circuit (Voc), and none of the reasonably price charge adaptors will handle that much voltage.

    I know that a couple of other people have used the "Nomad" mentioned in previous message, apparently with no problems, but it is a 6 volt panel and will not charge the also very common 7.2 volt gizmos.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    #4
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    Re: Charging cell phone?

    You might see if there is a USB adapter for your phone, most phones run off of a single lithium ion cell at 3.6-7 volts. You might look at your wall wart for answers, as it should tell you the output voltage.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • Rollin
    Rollin Registered Users Posts: 2
    #5
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    Re: Charging cell phone?

    Thanks for the help all! Was not sure if this was possible. Well the good thing is I learned something. Thinking I may just end up using the vehicle alternator to do my charging and supplementing the battery usage with a solar panel feed through the 12v power port. May end up replacing the starting battery with a marine deep cycle. BTW my phone is the Samsung Note 3.7v at 1500mv.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #6
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    Re: Charging cell phone?

    I have a Samsung Rugby: 3.7 V, 1300 mA (actually says 4.81 Wh on the battery).
    I can plug it in to the van (not running) and charge it up from "dead" no problem. The van still starts afterwards; it just isn't that big a draw to worry about. :D
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    #7
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    Re: Charging cell phone?

    Most of the newer smart phone run from 5v charger.

    The rub comes with the USB spec for maximum current draw. Many phones will only draw a maximum of 100 mA without a USB protocol communications to okay going to USB max of 500 mA.

    Since most smart phones can use more then 500 mA to charge their 1500 mAH+ battery, each manufacture has tricks done with either the 5th I.D. pin on the mini/micro USB connector or with high value resistors on the USB data lines to identify their unique 5v high amperage charger to allow the phone to pull more then 500 mA to charge the phone in the least amount of time. 700 mA to 1000 mA is typical.

    Auto cigarette lighter socket chargers are buck switchers that take the 12-15v cigarette outlet voltage down to 5vdc. Most can put out about an amp, some can do 2 amps. Their power conversion efficiency is about 80%.
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