JOAAO Ultra Slim 20000mAh Power Bank

JOAAO Ultra Slim 20000mAh Power Bank

The JOAAO Ultra Slim 20000mAh is no longer available.

Search instead for other JOAAO power banks.

Or check out the similar Aukey USB-C 20000mAh power bank.

The JOAAO Ultra Slim 20000mAh Power Bank at a glance

There are lots of things to love about this power bank. From a small producer of electronic goods based in India, the JOAAO Ultra Slim 20000mAh Power Bank is made with quality components and is an incredibly well thought out device. Most notably, it’s unique shape make it’s potentially one of the most versatile 20000mAh on the market.

Flight status: SAFE
  • 100 Wh (the official TSA limit is 100 Wh)
  • The capacity is clearly labeled on the backside of the product

If you’re planing to fly, read more about power bank TSA regulations.

  • Ultra slim design
  • Powerful, long lasting lithium ion battery
  • Sleek and user friendly design
  • Best battery indicator on the market
  • Limited number of USB outputs
  • Only one high speed USB output

Capacity & Charging speed

The JOAAO Ultra Slim 20000mAh Power Bank sits at about the same capacity as some of our other favorite power banks. 20000mAh is about what you want to be absolutely sure you’ll never run out of juice. We tested the JOAAO and were pleased with the results. Using some ultra thin lithium ion batteries, the The JOAAO Ultra Slim 20000mAh tested just above average for charging speed through it’s super fast 2.1A output.

Let’s talk about the outputs for a second. Unfortunately, the JOAAO comes with only 2 outputs. Not unheard of for a device of this size but certainly on the lower side. In addition to this, only one of the outputs is high speed. For people who are looking for a power bank to quickly charge 3 or more devices, this might not be for you. This is potentially a drawback of the shape of the power bank – not allowing room for more USB outputs.

In broader terms, the JOAAO passes with flying colors. They offer short circuit protection and there is an automatic shut down when the device is not in use.

How many times will the JOAAO Ultra Slim 20000mAh Power Bank charge my device?

iPhone 5s8.3 times
iPhone 6s7.1 times
Samsung Galaxy S64.6 times
Samsung Galaxy S74.3 times
Samsung Galaxy Note73.7 times
Sony Xperia Z5.5 times
HTC One M75.6 times
iPad Mini2 times
iPad Air 21.8 times
iPad Pro 9.71.8 times
Samsung Galaxy Tab S2 9.72.2 times
*Charging rates are a rounded approximation taking into account average battery condition, environmental factors and natural power degradation

Look and feel

We love the look and feel of the The JOAAO Ultra Slim 20000mAh. It has a sleek, smooth finish which handles fingerprints deftly. Both the outputs and the input are all on the same edge of the power bank along with the battery indicator. The battery indicator! Manufacturers can learn from JOAAO on this design point.

The LED is numerical so no more having to guess at unreliable flashing lights. Just look at the touchscreen LED, it’s an excellent indicator of how much charge you’ve got left. The edges of the power bank are rounded and the power button has nice give and feel. We didn’t encounter any aesthetic blemishes or inconsistencies with this unit and the packaging was really well put together. In fact if seemed like we were getting a high quality tablet when we received this in the mail!

Durability & Construction

The The JOAAO Ultra Slim 20000mAh Power Bank has a really solid feel. The machine work and joining all look top notch. We tested the USB ports with multiple cables and found no unnecessary give or lost connection. Time will tell if the casing and internal components will stand the test of time but we feel confident that’s a well made unit.

JOAAO also boast up to 10000 charge cycles under optimal conditions which is quite impressive. Their automatic shut down and short circuit protection are useful. I’d like more information however on exactly what other safety measures are in place to protect the device.


This is where the The JOAAO Ultra Slim 20000mAh Power bank really shines. If you think manufacturers of tablets were onto something with the shape of their devices I think JOAAO would agree with you. The power bank is the slimmest 20000mAh we’ve seen. Although perhaps not the smallest, it is certainly a convenient shape. If you already have your laptop with you, it easily slips into your laptop bag.

That’s not to say the JOAAO is small by any means. Don’t be fooled by the comparison picture showing it next to a touch screen device. This is a tablet, not a phone! Regardless, it sure beats carrying around a brick in your backpack. Compared to similar power banks, it’s a little heavier. There is a trade off to make I guess.

Technical Details

Size6.9 x 0.5 x 4.7 inches
Weight15.5 ounces
TypePower Bank
Charging Capacity20000 mAh
USB ports2
ColorsLight Grey, Black

The JOAAO Ultra Slim 20000mAh is no longer available.

Search instead for other JOAAO power banks.

Or check out the similar Aukey USB-C 20000mAh power bank.