Power an Arduino with some 18650 batteries

Hi,

I want to power my Arduino setup with 18650 batteries.

First, I thought about use a pre-built "power bank" like this :

https://www.aliexpress.com/item/Portable-USB-Charger-5V-2A-18650-Power-Bank-Battery-Box-For-iphone6-Smartphone/32837720204.html

But by looking on the net, I've found that these kind of power bank have a build-in auto power off feature : if there is less than 50mA of current being drawn, the power bank go to off.

This is not suitable for my needs : the arduino will not always be "on".

So I'm thinking about using one of these :

https://www.aliexpress.com/item/Free-Shipping-5V-Micro-USB-1A-18650-Lithium-Battery-Charging-Board-Protection-Charger-Module-for-Arduino/32710547395.html

and connecting it to 4x18650 batteries using this :

https://www.aliexpress.com/item/1-PC-Plastic-Battery-Holder-Storage-Box-Case-For-4x-18650-Rechargeable-Battery/32790023196.html

Does anybody has already done that before ?

Is it possible to :

  • power the arduino ? (I guess yes...)
  • charge the batteries while the arduino is powered ?

Thanks

Your suggested setup would work, but you Arduino would only have about 3.2 to 4.2V to work on - there is no boost circuit to make your 5V supply.

You can get cheaper power banks that are not "intelligent" and thus have no lower limit of current that you need to draw. Look for a power bank with no button to turn it off, or one where the button specifically is to show that remaining charge and nothing else.

// Per.

Thanks.

Do you have any reference to suggest for a "non intelligent" power bank ?

orel:
Thanks.

Do you have any reference to suggest for a "non intelligent" power bank ?

Not really. Look for reviews, see what people write about them.

Also you have to be sure to get one that has proper battery protection, otherwise your Arduino will be able to drain the battery completely and destroy it.

Proper power banks have protection built in - when the battery inside goes too low, the boost converter will shut off and the cell will be disconnected. On the cheaper ones, the boost converter will stop working, but you will still have approx 3V at the USB-plug, enough for the Arduino to still keep operating and it will continue to do so while the cell gets dangerously low. Most "proper" USB-devices that people use with power banks (Cellphones etc.) will just stop charging when the voltage drops any lower than 4.5V

// Per.

the batteries you speak of are lithium ion you can buy battery holders for these but one battery is 3.7 volts fully charged so you should use 3 in series to get enough voltage for the arduino on board voltage regulator. The batteries come in different maH rating such as 3000 milliamp hours but if you go this route buy a battery charger for these batteries only and never allow them to short out . Vape shops carry this stuff as we use them in our vaporizors

Thanks, but rather than use a battery holder and need to remove the batteries from it to use an external charger, I would like to use a "battery holder with internal charger", just like these power banks seems to be (but without limitations on drawn current)

rogertee:
the batteries you speak of are lithium ion you can buy battery holders for these but one battery is 3.7 volts fully charged so you should use 3 in series to get enough voltage for the arduino on board voltage regulator.

Please get your facts straight.
LiIon/Polymer chemistry is 4.2V fully charged. The 3.6/3.7V is the nominal voltage.

// Per.

I am trying to do the same thing and I saw these on Amazon and was going to give them a try with two 18650's to power my Arduino Nano 33 IOT. https://www.amazon.com/gp/product/B071RG4YWM/ref=ox_sc_act_title_5?smid=A1N6DLY3NQK2VM&psc=1

There is also an example sketch on how to monitor the battery with a "voltage divider".

grepler:
I am trying to do the same thing and I saw these on Amazon and was going to give them a try with two 18650's to power my Arduino Nano 33 IOT. https://www.amazon.com/gp/product/B071RG4YWM/ref=ox_sc_act_title_5?smid=A1N6DLY3NQK2VM&psc=1

There is also an example sketch on how to monitor the battery with a "voltage divider".

Seriously. This is a 3 year old thread. Make a new one instead of reviving this one.

// Per.