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landyacht318's avatar
landyacht318
Explorer
Sep 27, 2015

Evolving USB power

I've no devices which can draw more than 1 Amp through a USB port, never the less my several outlets can handle 2.1a or 3.1a total.

My favorite USB source is my Blue Seas:

https://www.bluesea.com/products/1016/Dual_USB_Charger_Socket

It maintains 5.09v under a 1 amp load, where as my other sources fall below 5v. This source and a short Micro USB cable can recharge my Samsung galaxy S4 mini phone noticeably faster than any other USb source I have.

It has a 15mA parasitic draw.

I just Noticed that Blueseas has a new version out available in January 2016, capable of 4.1 amps, and it only has a 1mA parasitic draw.

https://www.bluesea.com/products/1045/Dual_USB_Charger_-_Socket_Mount

I've not kept up with USB 3.0 or how much amperage newer devices can demand. I really like BlueSeas products and would certainly get this, if I required it, but I have 8 different USB options now and only 2 devices which require USB to charge.

But some on here might be more latest and greatest gadget savvy than myself and find the second link to be interesting.

Or perhaps want to talk about and inform us Neophytes where the USB standard is likely to go in the future
  • A device capable of charging 2 2.1 amp devices at the full rate at the same time is more impressive instead of a device where only one port can output that much. My contempt for Ciggy plugs/receptacles is also a factor.

    I fear the multicell 18650 battery packs. One could put 4 cells of all different voltages/states of charge in there and have themselves a Venting with flame, lithium toxic moment. A true trustfire moment.

    I'd hope it utilizes some protection features which would remove 18650 batteries from the circuit if they were not in line voltage wise with the others.

    I use a single 18650 cell USb power supply:
    http://www.amazon.com/Vktech%C2%AE-Portable-External-Battery-Charger/dp/B00R5TR7EG/ref=sr_1_3?s=electronics&ie=UTF8&qid=1427784516&sr=1-3&keywords=Vktech+18650

    It can only support 1 amp briefly before dropping to 0.88a max, but it can also charge the battery too and stops at 4.18 to 4.20 volts, as it should.

    I use old cells harvested from laptop batteries in them, but the higher capacity panasonic NCR18650b cells I bought at ~ 12$ apiece, work much better for longer.

    Any single 18650 cell which currently claims to have more than 3600mAH capacity, is smoking crack. 9000mAH? Come on. If that were possible, Teslas would have nearly triple their range.
  • I found that this 12 volt device also works great, providing up to 2 amps total and 4 ports!

    4 port 12 volt $4

    This 120 volt charger also has 4 ports, to charge multiple phones in one location.

    4 port 120 volt charger $5

    This is a portable battery powered USB charger. It will hold 4 batteries, 3.7V each and up to 9800 mA hour rating per battery, so it will be a 19 AH battery pack.

    $12 battery pack USB charger

    You will also need to order batteries and a charger to go with that battery pack.





    If you buy a battery pack, you might also want to buy a LED flashlight that uses the same battery, it will come with the charger that you will need anyway, and then order an extra 4 batteries. The batter pack will recharge any cell phone (with USB charger input) several times between recharging the 18650 batteries. 18650 battery is availible in several capacities, from 2000 mA to 4,000 to 9,800 that I bought a few days ago.

    Good luck,

    Fred.

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