I bought this iMuto 10,000 mAh powerbank on a lightning deal from Amazon for £12.79. It normally seems to be available for around £14-16. It’s pretty good value and I’m recommending this one.
Buy this from Amazon UK - This link contains an amazon referral link which helps me to buy more power banks to test.
In the box
The box is a generic cardboard box with a nice printed sleeve. It contains the power bank, a nice drawstring bag and a USB A to micro-USB cable. The power bank feels good in the hand, and has no obvious creaks or gaps in the case.
- Dimensions: 97 x 65 x 30 mm
- Weight: 242.3 g
- Micro USB cable length: 60 cm
- Input: 1 micro-USB
- Output: 2 USB A - 5V up to 2.1A
The power bank lists its output as “2*USB 5V/2.1A (Max.)“. This seems to suggest a 2.1A maximum across both ports.
Testing from a single USB port, the power bank delivers a steady 5V at 2.1A and turns itself off just over 2.5A.
Using both ports it’s possible to get slightly more current, but at 2.7A in total the supply voltage drops to 4.5V with the power bank switching off at 2.8A total.
Comfortably greater than the 2.1A maximum, so this is great performance.
The cable is 60cm long, is nice and flexible and has the manufacturer logo on both ends which is a nice touch.
At 1 amp the voltage loss was 0.18v which is 3.6%. At 2.1 amps the loss was 0.36% or 7.3%. This isn’t amazing, but neither is it an awful result - this cable is perfectly adequate.
Ignoring some issues with the USB load generating excessively noisy charts on my oscilloscope, the capacity test ran smoothly. With a purely resistive load the ‘noise’ was eliminated, so the cause was the load, not the power bank.
This is why the discharge chart is a bit ‘wobbly’ for the first hour - I improved that with some additional cooling of the load. I’ll look to changing it for the next test. I re-recorded this section of the video using a load that does not suffer from this issue.
The power bank delivered 29.8 watt/hours. The 10,000 mAh (10 Ah) cells in the power bank average 3.7V, giving us a maximum total power of 37 watt/hours (10 Ah * 3.7V). This means that the power bank reaches 80.6% of its claimed capacity, which allowing for loss from the conversion to 5V is quite reasonable.
The power bank cut off the power cleanly once it was discharged.
The remaining capacity the display of the power bank was reasonably accurate when measured throughout the discharge test. You can be confident that it’s a good indicator of remaining power.
Standby Power Loss
Seems fine. I’ve not measured the standby current as I’m not going to tear this one apart, but after 3 weeks of sitting idle it was still reporting 99% capacity.
I didn’t test this in the video, but this power bank seems to do pass through power just fine. There is a brief interruption of a second or so when the supply is unplugged.