I have this battery box that comes as part of the elegoo car kit v3.0 (cannot find any link to it since it is quite old now). Part of it is this battery box with 2 18650s:
you need to test if the batteries are in Series or Parallel ➜ check the voltage you see between the red and black wires with fresh batteries
they seem to be LiPo AA so the max voltage will go all the way between 4.0 and 4.2V and will decrease slowly then fall off quickly when you discharge them (see this Adafruit tutorial)
if they are in series you'll get double this voltage out, if they are in parallel you'll see this voltage and you'll get double capacity.
An UNO does need 5V minium to run fine, 7V through the Jack. so if they are in parallel it won't work. if they are in series you'll be above 7V and can power through the jack / VIN and this will go through the internal regulator of your UNO which will build a stable 5V. Don't power your uno through the 5V pin.
I doubt that. There is presumably an Arduino or at least a ATmega328 involved somewhere judging by the pin numbers. As such the board could be a useful way of plugging in external devices such as sensors and motors
The batteries are in series , as can be seen by the connector strip at one end . So you have around 7.4 ( upto 8?) volts and you can power an Arduino via the vin or the socket
I do not think you will get much life from that battery. The motor, 28BYJ-48 stepper motor requires 240mA current to operate. Note: it also consumes power at an idle condition so do not expect much battery life.
Post an annotated schematic as to how you will be wiring this, the driver etc may also require current. You also need a 5V regulator for the motor as the Arduino is not a power supply, using the 5V from the arduino may possibly damage it.
In the instrctional pdf of the elgoo kit, they are powering both the arduino via USB and the power supply module, so I now have 2 questions:
Is there a way of also powering the arduino from the breadboard to eliminate the need for 2 power connections?
What kind of power adapter sohuld I get for the power supply module? I only have one of those that connect to a 9v battery but I am not sure how long that would last
If you are powering the Arduino from USB, then you can probably get away with powering the motor from the Arduino's 5V pin. The Arduino bypasses the on-board 5V regulator when it's powered from the USB port.
If you are powering the Arduino from a DC source like a battery, then you can NOT draw that much current from the Arduino's 5V pin. The regulator on the Arduino can't handle the load. With a battery, connect the battery positive to the Vin on the Arduino, and to a separate 5V regulator that can power the stepper.
I do NOT recommend using a 9V battery to power an Arduino. They are designed for low current applications. Just the Arduino itself is about all a 9V battery can handle, and it won't last all that long.
The battery box with the two 18650 batteries in it should be just fine for your project. Another choice would be a set of four AA batteries in series.
Your battery box is set up in series. Assuming the 18650 are in good condition, you'll get a max voltage of 8.4v, nominal voltage of 7.2, and to be safe, only run them down to around 5.8-6volts. I use the heck out of 18650s pulled from power tool batteries. I also use the heck out of buck boards. You could build a nice power block using both step down buck boards like these:
HiLetgo 10pcs RC Airplane Module Mini 360 DC-DC Buck Converter Step Down Module MP2307 4.75V-23V to 1V-17V https://a.co/d/8li61iH
And step up buck boards like these:
Dorhea MT3608 DC-DC Step Up Boost Power Converter 2A Module Adjustable Step Up Voltage Regulator Board Voltage 2-24V to 5V-28V Output Voltage Mico USB (Pack of 10) https://a.co/d/fS93jTA
Throw one of these in the mix and now you have a rechargeable power supply with low voltage protection for your bread board.
Fully adjustable the buck boards can source up to 3amps of current. I've tried those bread board power supplies and maybe it's me but they never seemed to work for me.
If you are here, then you are a maker. Make this and be happy with the variable outputs.
Or, just buy a power bank to charge your phone and modify a charging cable to plug into your breadboard.
