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Simple Gear Tests and USB Recharging


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Home Forums Campfire Editor’s Roundtable Simple Gear Tests and USB Recharging

Viewing 8 posts - 1 through 8 (of 8 total)
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  • #3725947
    Rex Sanders
    BPL Member

    @rex

    Companion forum thread to: Simple Gear Tests and USB Recharging

    In his new column, Simple Gear Tests, Backpacking Light author Rex Sanders provides suggestions for at-home gear tests you can do with minimal time and expense. First up – a plan for verifying the capacity of your USB-rechargeable devices.

    #3725959
    Steve M
    BPL Member

    @steve-2

    Locale: Eastern Washington

    Nice work…thanks Rex.

    #3726161
    James Taylor
    BPL Member

    @james-taylor

    Locale: Indy

    During preparation for an unsupported FKT attempt, I tested 5 different Chinese power banks from Amazon to see if their advertised capacity matched their actual capacity, using this same method. 4 of the 5, advertised as 26,800 mAh, were actually 20,000 mAh. The only one that advertised capacity honestly was a $90 battery. Most $20-$30 batteries falsely advertise higher than their true capacity because there is no accountability for these companies on Amazon.

    #3726172
    Jerry Adams
    BPL Member

    @retiredjerry

    Locale: Oregon and Washington

    good testing, thanks, interesting results

    Charging slows down as the device nears 100% charged.  For example, maybe it takes 1 hour to charge to 80% and another hour to charge the rest of the way to 100%.

    I wonder if efficiency drops as you near 100%.

    For example, if you just charge to 80%, could you extend the number of days you could do with the same USB power bank?

    #3726202
    NoCO-Jim
    BPL Member

    @noco-jim

    Locale: NoCO

    Nice review, Rex.

    Just a detail note on both Klein meters, from the manufacturer:

    “This meter will NOT display current below 50 milliamperes, even if it is allowing this to pass through. NOTE: The display will show zero current.”

    #3726225
    Rex Sanders
    BPL Member

    @rex

    James: (Clutches his chest) You mean some gear makers don’t tell the truth? Seriously, this is why I’m working on Simple Gear Tests so more backpackers can find out for themselves. Can’t test and compare a gazillion cheap, gone-tomorrow whatevers on Amazon and other wild-west marketplaces.

    Jerry: I’ve wondered about efficiency dropping, too. But from what I’ve observed during this testing and what I’ve read elsewhere, smart devices like iPhones in effect “lift off the gas pedal” and pull fewer watts over 80% charge, to extend internal battery life. They also start slow near 0% and ramp up at about 20%. I don’t think this has a big impact on efficiency. Might be worth testing.

    NoCO-Jim: If a device is consuming 49 millamps at roughly 5 volts (but showing 0 mA on the Klein), that’s about 1/4 watt. My dad used to say: “Don’t sweat the small stuff.” Many years later I added: “… unless it adds up to make a real difference.” I plan to test overnight recharging for several devices and see if it does.

    — Rex

    #3726352
    Eric Blumensaadt
    BPL Member

    @danepacker

    Locale: Mojave Desert

    Thanks for this review. Very helpful, especially the observation that wire connectors take up some amperage as well as heating a battery via charging.

    I have two chargers, a smaller one rated 4,00 MaH and a larger smart phone-sized one at 10,000 MaH.

    Both can charge my Phone 10C from 20% to 80% in less than an hour.

    #3726358
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    Hi Eric

    Pedantic: I think you meant 4,000 mAH and 10,000 mAH?
    A capital M means Mega, which is a bit different.

    The wire cables cause some voltage drop.

    Cheers

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