OK, the other day someone suggested that I head over to eBay and, for a laugh, look for the largest advertised power bank I could find.
Within minutes I'd found one that claimed to be a whopping 9,000,000mAh; amazing, since it's small, and a chunky power bank like the Zendure SuperTank Pro is only 26,800mAh.
Oddly, the capacities topped out at 9 million mAh, and I couldn't find a 10 million mAh power bank. I'm not sure whether that would just be too ridiculous, or 9,000,000 looks bigger than 10,000,000.
Anyway, I had to buy one. I expected it to be bad. And £14 (about $20) and a few days later, I got what I deserved.
Before I show you the power bank, I want to share how the eBay listing goes to lengths to explain why the power bank doesn't have a capacity rating printed on it.
OK, the power bank. It's the typical cheapo power bank with a solar panel and some rubber around the edges to make it look rugged. Beyond this, there's nothing about the power bank that's designed to prevent water or dirt ingress.
It has a single microUSB port for charging, along with two USB-A output ports. It has a 9-LED flashlight on the back, and some cheap rubber flaps cover the ports.
On stripping it apart, I found the typical circuit board for these kinds of power banks (the board has a 2015 date screen-printed on the board). The battery didn't have any markings, but it is the size I'd expect for a 10,000mAh cell (and discharge tests showed that it was indeed a 10,000mAh cell, to within 10 percent).
The power bank promised a maximum output of 2.1A at 5V, but when I put it under a 2A load the voltage dropped to 4V and the power bank quit within a few seconds.
So, what I ended up with was a power bank with less than 1/900th of the rated capacity that wasn't capable of delivering the maximum rated output. The LED flashlight was OK, but the on/off switch was poor and became unreliable after a few presses.
Oh, and the power bank also came with a compass on a keyring; unfortunately, the compass points to the metal ring in the keyring, so even that's junk.
It's almost like this power bank's entire life's purpose was to take $20 out of my bank account.
Now, as is the case with products like this that are sold in the UK, I liaise with UK trading standards officers to get products like this removed from sale.
Bottom line: don't waste your money.