A tale of very big USB-C power banks – and why you should buy one

USB-C power bank

 With smartphones now having 4,000mAh batteries and tablets/laptops up to twice that the need for a big USB-C power bank supporting USB-C power delivery 2.0 or 3.0 has become mandatory for the road warrior.

GadgetGuy found a few USB-C power banks that meet those needs.

We will look at each later, but for now, we needed to define the review paradigms

  • Weight and size. You want something you can throw in the briefcase or backpack
  • Charge times – as quick as possible
  • Charge method – USB-C and/or micro-USB
  • Output Ports – USB-C and at least one USB-A
  • USB-C Power delivery specs

We were not able to test power bank capacity, but these days truth in advertising makes it hard to overstate, so we took that at face value.

USB-C power bank test setup

We used a Nokia 7.1 (GadgetGuy review here – great $499 phone too) with a 3060mAh battery that using the GeekBench 100% load battery killer test lasts about 7 hours. That means it draws about 437mA at 100% load. In real use phones never draw 100% all the time and most draw 100mAh when idle.

We charged all using a Belkin 45W USB wall charger at $79.95 that delivers USB-C PD 2.0 5/9/12/15/20V at up to 3A. A 45W charger makes a huge difference over a 5V/2A USB charger – we assume it is 4.5 times faster.

First some science

Electricity behaves predictably – volts x amps = watts. One amp = 1000mA. And mAh is milliamp per hour.

So, a 5V battery capacity of 10,000mAh can provide 10A (50W) of power for one hour, 5A (25W) for two hours, 2.5A (12.5W) for three hours etc.

The smart device it powers will have a battery, usually measured in mAh but what that means is if you know the power it draws you can calculate the time it should last. So, if you have a 4,000mAh battery and it lasts say 10 hours under 100% load the maximum draw is 400mAh. In this test we don’t care about what the device draws so much – we care if the battery can charge the device how fast and how many times.

And finally the fiddle factor – charging is not 100% efficient and energy is lost via heat. Even though a USB-C power bank is advertised as so many mAh it can only ever achieve about 70-80% of that.

Confused – well yes, it is rocket science.

Recharging times using a USB-C power delivery 45W charger opens an even a larger can of worms.

USB-C power delivery 2.0 (we will call this Quick charge 3.0 technology) adds more complexity. When charging a battery (either the power bank or the smart device), the device communicates with the charger and negotiates a downstream flow of voltage/amperage between a low of 3.2V and 20V in 200mV increments. What usually happens is that it starts high (say 20V/.9A, 18W) until it fills to say 50% (that is why most fast chargers quote 50% in 30 minutes) then it has to drop to 9V/1.5A (13.5W) from 50-80% and then tops up at 5V/2A (10W) for the rest. Even a quick charge battery can take a couple of hours, but it’s a hell of a lot faster than USB-A 5V/2A charging.

Laser 20,000 USB-C  Power bank

  • Smallest at 425g
  • Huge flexibility with four USB-A, 1 x USB-C outputs
  • Best value (at RRP) $129.95 – .00649 cents per mAh
  • 20,000mAh is all you need as it will power a 4K Lenovo Yoga 920
  • Complies fully with Quick Charge 3.0 standards
  • Comes with USB-C to USB-C and USB-A to USB-C cables
  • Head says, “Buy this”
USB-C power bank

Cygnett 20,000 USB-C  Power bank

  • Almost the same specs as Laser with five extra amps output
  • Cost .007495 cents per mAh
  • Complies fully with Quick Charge 3.0 standards
  • Rubberised non-slip finish looks great
USB-C power bank

Cygnett 27,000
USB-C  Power bank

  • Highest output of all but heaviest at 649g
  • Cost .00666 cents per mAh
  • Complies fully with Quick Charge 3.0 standards
  • Rubberised non-slip finish looks great
  • Has a second USB-C output (maximum 5V/2.4A)
  • Heart says to buy this
USB-C power bank

RAVPower 26,800
USB-C  Power bank

  • Amazingly light at 463g for 26800mAh
  • It achieves the light weight though different battery technology and only outputs a maximum of 47A.
  • Mostly complies to Quick Charge 3.0 standard –no 12V/3A output
  • If you get it at the discount price of $99.95 the cost is .00372 cents per mAh otherwise it is .00596 cents per mAh
  • Nice accessories
USB-C power bank

GadgetGuy’s take – and the winner of the USB-C power bank is?

They are all fit for purpose.

If you want massive capacity, it is hard to ignore the Cygnett 27000 but the RAVpower 26800 at $99.95 on special is the winner. In real-world tests, both took over 5 hours to full charge.

Cygnett’s 20000 is more pocketable, but in tests, it took nearly as long to charge as its 27000mAh big brother.

The winner is Laser’s 20,000 mAh that offers four USB-A ports as well as USB-C power delivery in the lightest package. It also charged significantly faster at 3.25 hours than the others making me feel it has implemented QuickCharge 3.0 the best.

You will be happy with any of them.

Feature Laser Cygnett Cygnett RAVPower
mAh capacity 20000 20,000 27000 26800
mAh measured 3.7V/20A=74W 3.7V/20A=74W 3.7Vx27A=99.9W 3.7Vx26.8A=99.16W
Input micro-USB Yes No No Yes
Input wattage max 5V/2A=10A N/A N/A 5V/2A=10A
Input USB-C Quick Charge 3.0 same same same
Input USB-C 5V/3A
12V/3A 14.5V/2.4A



Input Wattage max 36 30 30 30
Theoretical recharge time in hours USB-C Quick Charge (real times about twice these) 2.05 2.5 3.33 3.31
Theoretical recharge micro-USB 7.4 N/A N/A 9.916
Output USB-C 1 Quick Charge 3.0 same same same
Voltage provided 5V/3A
12V/3A 14.5V/2.4A

Output max Quick Charge 3.0 40 45 60 30
Output USB-C 2 N/A N/A 5Vx2.4A=12W N/A
Output USB-A 1 5Vx3A=15W 5Vx2.1A=10.5W 5Vx2.4A=12W 5Vx3.4=17W
Output USB-A 2 Or 3A total if 1 and 2 are used together 5V/3A
Maximum 18W
N/A Or 5×2.4A=12W in total if used with USB-A 1
Output USB-A 3 3A N/A N/A N/A
Output USB-A 4 Or 3A total is 3 and 4 are used together N/A N/A N/A
Total Output wattage 55 63 72 47
LED check 4 4 4
USB-C to USB-C cable Yes No No Yes
USB-A to USB-C Yes Yes Yes No
USB-A to micro-USB 2
Soft case No No No Yes
Weight g 425 454 649 463
Price $129.95 $149.95 $179.95 $159.95 but on special for $99.95
Charges MacBook Pro 13 2018 60W Yes Yes Yes Yes
Charges Lenovo Yoga 920 2018 70W Yes Yes Yes Yes
Charges Samsung Galaxy Note9 4000mAh Up to 5 times Up to 5 times Up to 6.7 times Up to 6.7 times
Charges iPhone XS Max 3179mAh Up to 6.3 times Up to 6.3 times Up to 8.4 times Up to 8.4 times