Powering Arduino from a power bank

Using Arduino General Electronics
#3

ppeterlin: My guess is that in addition to maximal discharge current, power banks also have some minimal discharge current, and shut off if the discharge current is below this threshold. They treated my Arduino as "leakage" and shut off.

Yep. That's exactly what the manual says - though not in so many words.

So why?

Well, the "power bank" contains a 3.6V lithium battery, so to put out regulated 5V, it contains a power up-converter. The power converter is not perfectly efficient so it uses some power to operate even if there is no load, and of course, you are running the indicator LEDs. To prevent the power converter itself and the LEDs from discharging the battery, it does not turn on at all until you press the "Power" button, and if it detects that it is not being used significantly for 5 seconds, it turns itself off to prevent discharge.

#4

Low load turn off is a "feature" or many battery chargers. Some of them have an "always on" setting.

There are several threads I have found which document using a pulsed load to keep the battery pack running. http://www.dorkbotpdx.org/blog/paul/battery_pack_load

This solution did not work with a charger I had, and it is dependent upon the charger you have.

#5

I have the same issue and endup with this simple circuit.
What it does is basically giving a short burst of to fool the powerbank every something second.
https://www.dorkbotpdx.org/blog/paul/battery_pack_load

This particular arrangement works for my XiaoMi PowerBank (20A).
Total power drawn is roughly 3.5mAh (per hour), so its not too bad.
Assuming it runs at 5v (from the USB)… 0.0035Ah x 5v = 0.0175Wh
If you run it for 24 hours… 0.0175Wh x 24 = 0.42Wh
Assuming the powerbank only holds 15A (x3.7v = 55Wh) …
this circuit will finish the battery in about 4 months.

c019abc9-be70-498c-84a3-514aa36e9d69.jpg

#6

stormizer Thank you very much! I've been looking for this for a year! What do you think: does the circuit below require the same endup that you did? |500x143 From left to right: 1) 5V 1A Micro USB 18650 Lithium Battery Charging Board Charger Module+Protection Dual Functions TP4056 (as Ali says) 2) 18650,3.7 V Battery 3) Mobile booster ( 3.7 to 5V DC-DC step up, as far as I undertsand) Thank you!

#7

No, the booster has no off mode. (How would you turn it on without a button?)

#8

septillion, Hi! The circuit above has been borrowed from here Do you mean by "button" ON\OFF power switch?

#9

For example. Or a push button like most power banks etc. But the boost converter has non of that. It’s as simple as power in = power out.

Same goes for the charger/protection board. As long as the battery has enough power (aka, not empty) and there is no short circuit / overload there is power at the output.

#10

septillion, thank you! What is the best place for an ON/OFF switch here? Is it between 1 and 2, or 2 and 3?) 1) Micro USB 18650 Lithium Battery Charger Module+Protection Dual Function.

2) 18650,3.7 V Battery

3) Mobile booster ( 3.7 to 5V DC-DC). Thanks

#11

Between 1 and 3. Those charger/protection modules don't draw jack so no need to disconnect the battery from it. This way you can still charge the project when the switch is off.

#12

septillion, I'm grateful to you for answering all my questions! Now I have to order all this stuff to try it out.

#13

Old thread I know, but I finally found a power pack that doesn’t turn off automatically. All the ones made by TalentCell. This one for example:

I should mention that I’ve only tested the one in that link, but I believe they all stay on permanently. Very refereshing after fighting auto power off for so long.

#14

is it just me, or is it strange that people want to use a power bank as a power source ?!

just because they both "provide electrical power" doesn't mean that they are the same thing.

it's all down to how they are designed to be USED ! (the bank is a portable unit to recharge your battery - the power source)

look at it this way - would you think of taking a battery charger, solder cables to it's positive and negative terminals, and then try to power something with it ?!?!

#15

What's so strange about it? It's convenient (except for the auto power off). And there is nothing charger about a power bank, it's just a 5V voltage source. All the charging magic needs to be done in the device connected. That's why a power bank isn't called mobile charger ;) And yes, the name USB charger / phone charger when you mean this is misleading / "wrong". It's simply a USB power source.

#16

Heading along the same path as septillion. What is the difference between a power bank and lithium ion battery and a USB charger with a voltage boost circuit (such as https://www.adafruit.com/product/2465)?

#17

You don't need external circuit, you can use your Arduino itself for keeping the power bank running. Just put a 22R resistor between 5V of USB in and a pin (e.g. 1C) of ULN2803. Then supply signal to pin 1B of ULN2803 from Arduino for 250 ms in every 5 sec. This signal "sinks" the current provided by the power bank through the resistor. For me this configuration is working fine.

So the only external component you need is the resistor and a ULN2803. You can set the optimal timing of the signal in the sketch to find the minimal power consumption which still keeps the power bank running.

#18

To keep it real simple, I added an LED & resistor to my circuit off to the side and it apparently draws enough to avoid the auto shut off problem. Obviously uses constant power so depending on your application this may or may not be optimal.

#19

BabyGeezer: look at it this way - would you think of taking a battery charger, solder cables to it's positive and negative terminals, and then try to power something with it?

Don't know about soldering cables, but using the clips, I use one to test motors and stuff and to run my tyre pump. :grinning:

#20

I've found a very simple solution, that works at least with my power bank (Silicon Power SP power S105, sold by Costco). This power bank does not switch off when it is being charged (through the micro-usb plug). So, I just make it believe it is being charged by supplying 5V to the power pin of the micro-usb cable... Since connecting directly the micro-usb input to the other usb output or the 5V pin of the arduino would draw a lot of current (charging the power bank with its own power output!), I connected a 27 ohm resistor in between (I've not tried with higher values for smaller current yet). It worked: no switching off for a whole afternoon and night while running an arduino uno measuring a chinese calliper, and very little power wasted. On the other hand, I had no luck with the pulsed load solution with my power bank...

#21

Hi all. Found this one which is mentioned which seems to do exactly what people need: https://www.voltaicsystems.com/always-on

Paul

#22

I had the same problem but solved it with a 555 timer and 3906 PNP transistor, this circuit draws about 200 mA for 1.6 seconds every 13 seconds, but you have to experiment a bit with the main capacitor and the resistors on the timer side of the 555 chip, because these power packs have different cut-off current settings.

See the website for the circuit diagram.

https://www.instructables.com/id/Current-Pulsing-Keeps-Power-Bank-Active/

It works fine for me!