Power banks are designed for charging phones. When a phone is fully charged, it doesn’t draw current and the power bank switches itself automatically off, as it should. If it wouldn’t, it would drain, because of the inner circuit transforming the actual 3.7 V battery voltage to 5.0 V.
But this auto switch off feature makes these power banks unusable for other purposes, unless extra action is taken. One very popular use is to power DIY electronics like Arduino stuff with a power bank. For this, one needs to put an extra load on the power bank, to assure that the power bank is not switching itself off. This is easily done, but it would be even more easily done, if we knew the specs of the power banks.
I have an Anker Astro E1, model A1211. The leds stay on for 10 seconds, when I push the button. Is that an exact time or does it depend on the amount of current drawn? How much current must be drawn for the power bank to stay on for another 10 seconds? Knowing these numbers would minimize the needed load, extending the battery life to its maximum. A typical setup could be a circuit, which every 8 second switches on a load that draws 100 mA for 200 milliseconds.
If power bank manufacturers would publish these specs, I bet it would raise the popularity of their power banks.
Anker uses not only phone tech in their powerbanks (PBs) such as Qualcomm fast charge, but also power IQ.
The power IQ (obvs depending on size etc of PBs) gives the device the power it wants. So whether charging a phone or gocam, or switch, each device gets what it needs to recharge, as it would via a wall charger. Obvs a PB cannot maintain such a high constant power, as a wall charger, so it takes longer.
Obvs the king of PBs is the powerhouse range, then down to the more portable 26800 range.
If you want to know more information, I’d suggest looking on Amazon (the details seem more full on there). Or emailing Anker support … firstname.lastname@example.org and.asking for more specs on the items you’re interested in.
If the power bank says 5 V 2 A, I expect it to deliver up to 2 A with 5 V. If more than 2 A is sucked, anything can happen. Voltage drops, PB shuts itself off, PB catches fire… But as long as not more than 2 A is used, the PB should hold its 5 V, until the juice is drained.
I might e-mail to Anker customer support. But my impression was that the Anker support guys follow this forum. If they do, I repeat:
- How many seconds does an Anker PB stay on, when there’s no load?
- How many milliamps is needed to keep the PB stay on and for how many milliseconds?
I ran some tests. The Anker power bank shuts itself in 30 seconds, if the power usage is only 30 mA. Strangely it turns itself on, if you connect something less than 30 mA, but it doesn’t stay on. If the power usage is 110 mA or more, the Anker power bank stays on.
Another brand I have stays on, if the power usage is as small as 15 mA. If the usage is smaller, it turns itself off in 24 s. Just a short usage (100 ms) is enough to keep it on for another 24 s. This kind of behaviour would be desired. The phone charging works, but the power bank could be used for much more.