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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
- This topic has 7 replies, 7 voices, and was last updated 3 years, 5 months ago by Roger Caffin.
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Aug 27, 2021 at 9:00 am #3725947
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.
Aug 27, 2021 at 11:27 am #3725959Nice work…thanks Rex.
Aug 29, 2021 at 5:49 am #3726161During 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.
Aug 29, 2021 at 8:34 am #3726172good 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?
Aug 29, 2021 at 2:48 pm #3726202Nice 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.”
Aug 29, 2021 at 5:48 pm #3726225James: (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
Aug 30, 2021 at 11:08 pm #3726352Thanks 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.
Aug 31, 2021 at 3:39 am #3726358Hi 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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