USB power packs - general thread

[rr100]

With the rise of non-removable batteries a new type of accessory is found everywhere: USB power packs (or whatever the appropriate name is for the devices that have some - usually - LiIon batteries inside and can charge a phone/tablet or even sometimes a small notebook).

Most reviews on the net are quite shallow and of course almost nobody ever speaks about safety or true performance of those devices. I think many of us, on this forum, would do a good job of evaluating those.

I'll start by posting the results of a test with a resistive load on (still in progress):

Anker 10000 mAh

(not my video).

[baoshi]

I  did some limited review last year. http://www.ba0sh1.com/mobile-charger-review/
Forgive my poor English though

[Balaur]

Hey, that's actually a good idea.

I may contribute later with a more in-depth analysis of the Tenergy 8000 mAh External Energy

As a quick review, I would like to say that I'm rather unimpressed by the device:

• 2 Amp capability on the high current port is a joke. The voltage drops to some 3.6 volts!
• Slow recharge. The power input connector is a jack, not USB, and the device doesn't draw too much power, making recharge times on the order of some 10+ hours
• The power indication/power on circuitry is very sensitive, it sometimes starts when just touching the ports

On the "not good for me, but it was expected" side, the 2 amp port is configured for Apple products only. This is the intended design, and it's not a negative comment on the product, of course. I had to remove the existing resistors on the USB DP, DM lines and connect them together in order to be able to quickly charge my Android tablet. The interesting part that originally, my Nexus 7 tablet didn't wanted to recharge on either low or high current port when using a standard USB cable. The provided (male Jack to male USB cable) + a (female Jack to micro USB) combination was OK, but come on!

On the good side, it provides (at least on paper) a lot of capacity for the money. I would have to check that through some measurements though.

Cheers,
Dan

[amyk]

]Slow recharge. The power input connector is a jack, not USB, and the device doesn't draw too much power, making recharge times on the order of some 10+ hours

If it's really 8000mAh then at the 500mA USB default it'll take ~16h to charge, probably closer to 20h if counting the long "soak" phase for lion charging.

[Balaur]

]Slow recharge. The power input connector is a jack, not USB, and the device doesn't draw too much power, making recharge times on the order of some 10+ hours

If it's really 8000mAh then at the 500mA USB default it'll take ~16h to charge, probably closer to 20h if counting the long "soak" phase for lion charging.

Yes, I'm aware of this. I don't have a definitive measurement, and I haven't gone through a full cycle yet.
I'll be happy to get back with some more detailed data.

Cheers,
Dan

[rr100]

Be aware that 2A is rather high for usb cables and while they won't burn the voltage drop is probably quite significant (in other words it is crucial where you take the voltage reading).

I have the results for mine:

Anker 10000 mAh
7 months old, rarely used, except for a couple trips and I had to leave it for 3 week plugged-in used as a permanent 5V power supply (I don't know how happy it was about that as it would not stay in a stable state, it would start discharging, charging, etc)
results on resistive load 2x4.7 ohm series attached (be aware the header of the file is shifted, 2.59 for example is VxA.

Total results based on VxA readings:

33.28 Wh

that equals:

6.67 Ah at 5V
9.24 Ah at 3.6V

I added an attachment with the charging log from empty. Charging is at 12V (variations in voltage are at first because my power supply probably takes some time to worm up and then I was trying to fiddle with it to compensate for the voltage drop on the ampermeter).

43.43 Wh go in
charging goes for 212 minutes with 0.9-1A then it starts to drop off
it takes about 277 minutes total to finish the charge, including those 212 above

[mianchen]

I've cracked one open in this thread: https://www.eevblog.com/forum/reviews/'power-bank'-tear-down/

[icpart]

I  did some limited review last year. http://www.ba0sh1.com/mobile-charger-review/
Forgive my poor English though

Thanks a lot for this great review. For a long time I was wondering what have is inside of those chargers.