12V 100W panel to charge small USB battery bank?

otterslideotterslide Registered Users, Users Awaiting Email Confirmation Posts: 1
edited October 2019 in Solar Beginners Corner #1
Is it possible to hook up a 12V 100W panel to charge a USB battery pack, like the Anker PowerCore+ 20100, or maybe two of them at a time?
I know it doesn't make sense to  have 100W for this small battery bank,  it's just a temporary use I'd like to have if possible until I can get some more expensive deep cycle batteries.
Basically, I want to gather some 100W panels and slowly build up a system, but as I gather the parts, get some use out of the panels. I can use the Anker Powercore to run a laptop, so that's pretty useful.
I know charge controllers require a battery.. so I'm not sure what kind of regulator may be out there for providing USB power output? The PowerCore needs 10 hours at 2A to charge completely.. I think 5Vx2A = 10 watts is all it needs really?

The small foldable solar panels have USB outputs on them, so I basically need some circuit like that, which can take 12V and turn it into a regulated 5V.


  • mcgivormcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    There are charge controllers that have USB outlets, you would however still need a 12V battery to power the controller, this would allow the hours needed as time would be powered bu the 12V battery after the sun can no longer support the load. 
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • BB.BB. Super Moderators, Administrators Posts: 32,088 admin
    A lot of the Anker 12 VDC USB "cigarett" USB power converters are rated to run at 24 VDC... I have used quite a few on 12 volt cars without problems, trying one on a "12 volt panel" (really around Voc~22 VDC/Vmp~18 volts)--I would give one a shot (no particular reason I picked this one--Other than the 24 volt support and USB C support):


    PowerDrive PD 2 is designed to charge phones and tablets. To charge laptops like MacBook and Huawei Matebook at full speed, you will need a charger with at least 30W output.

    At a Glance Input: 12V / 24V ⎓ 4A; USB-C Output: 5V ⎓ 3A / 9V ⎓ 2A ; USB-A Output: 5V ⎓ 2.4A (max.). Dimensions: 35.7 × 35.7 × 68.6 mm / 1.41 × 1.41 × 2.70 in; Weight: 35 g / 1.23 oz

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PhotowhitPhotowhit Solar Expert Posts: 5,683 ✭✭✭✭✭
    If you are cheap and a 'do it your selfer', you might search  for <usb  solar  regulator>  on ebay for  a nice compact unit that will work from  6v - 20 volts. I bought 2 different  and used them with   a 30 watt, 6v, solar shingle, just a trial, and never tried with a 12volt nominal panel. About $1.50 and 3 weeks, can be  had  from  US suppliers  faster  for about double.

    I saw  this  while  looking for a  similar  produce on Amazon, a couple bucks  and no soldering!;

    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.
  • JeremyJeremy Registered Users Posts: 5
    To select a suitable charge controller you simply take the rated output of the panel and divide by the nominal voltage of the battery. So 100W / 12V = 8.33 Amps. Therefore a 10A solar charge controller will do the job and will typically have a power range up to 130W for 12V system. 
    onvert 12v to 5v using Zener Diode! check this video:  https://www.youtube.com/watch?v=7SvSLPW3NJc
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