i'm looking to power my Arduino (and also a raspberry for another project) with a power bank, the ones that are used to charge smartphones.
I bought a Li-Po 10 000mAh 5V 3.1A one, as you can see in the picture.
The problem is there is a system that cut the power when the power consumption is too low, and apparently one arduino uno is too low. So my battery turns off after 30sec... Do you know any battery that doesn't have this system ??
Anyway, I opened it to see what's inside and if it's possible to shortcut this system. Turns out it's written 3.7V 5000mAh battery... Am I being duped ?
And if someone knows any components on this electronics board, in order to shortcut the automatic power off...
simmoinard:
Anyway, I opened it to see what's inside and if it's possible to shortcut this system. Turns out it's written 3.7V 5000mAh battery... Am I being duped ?
You bet!
It's like the famous "internet inch" used in certain - err - physical measurements.
I understand this gadget apparently does not have the shut-off problem, but you might want to research it further:
eBay
Just to be sure :
It is marked inside 3.7V - 5000mAh - 18.5Wh.
My voltmeter shows 3.7V at the output of the battery, and 5V at the output of the USB port.
So 18.5Wh/5V = 3700mAh is my real battery on the USB port ??
Paul__B:
I understand this gadget apparently does not have the shut-off problem, but you might want to research it further
But the one of that gadget I tested had another problem.
When the battery goes flat, it turns off, but then as the battery recovers it turns back on again. So you hqave whatever device its powering cycle on\off a few times as the battery is dying. Not helpful behaviour.
Basically a power bank is designed to charge mobile phones. Not for any other purpose, and typically
require modification to disable the auto-shut-off, which may be possible if you can figure out the circuit.
Annoying, basically.
A power bank is not a power supply, its a LiPo battery charger...
4 NiMH AA cells in a holder provide about 5.2V without such issues.
@6v6gt it is interesting, but as I understood it may not work with my project as the arduino can go in low power for a long time, more than 2sec.
@srnet, it is said in the Powerbanks 2, 2C, 2S, and 3 that it effectively works with systems such as bluetooth headset, smartwatch, etc : https://www.mi.com/fr/battery2c
If it's really 20000mAh, For 25€ it looks very good ! I'll try it !
I'll try also the NiMh batteries.
Thank's for the info!
simmoinard:
. . . @6v6gt it is interesting, but as I understood it may not work with my project as the arduino can go in low power for a long time, more than 2sec.
. . .
This is not correct. The load that that circuit puts across the power bank, to keep it alive, is completely independent of the arduino or any other load that you may put on the power bank.
If it is a really low power project, then maybe normal alkaline batteries may be a good alternative. For example, I have a barebones arduino with a radio module. It wakes up and transmits once every 32 seconds. The batteries are still good after 2 years.
When the battery goes flat, it turns off, but then as the battery recovers it turns back on again. So you hqave whatever device its powering cycle on\off a few times as the battery is dying. Not helpful behaviour.
I have one of these and have only begun to test it. Reading the documents I know there is a circuit that will disconnect the battery when the battery voltage is so low there is a risk of permanently damaging the battery.
Is this what you are referring to or is there another issue I should look for?
