#171 External Battery Monitor from your Arduino

Don't let a flat battery ruin your data gathering! This simple trick shows you how to detect a failing battery.
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You can read all this and MORE (eg Circuit Diagrams, Sketch) in my GitHub:
https://github.com/RalphBacon/171-Monitor-Your-Battery

So your battery-powered project runs on a buck-boost (or other DC to DC converter) and you need to monitor the voltage of the LiPO rather than the VCC supplied to the Arduino (as shown in video #160).

A simple configuration at the Arduino and a simple potential divider and it's job done! Then you can monitor the voltage of your LiPO (or car battery etc) and **get early warning** when it is on the slippery slope to complete discharge.

Remember, too, that you don't want to run a LiPO (eg an 18650) any lower than 3.0v or you will **permanently damage** the device and it may never fully recover. If your battery has protection circuitry included (18650 batteries WITH protection are slightly longer than unprotected ones) it will automatically shut it down at 3.0 volts anyway.

The sketch is so simple I'm almost embarrassed to upload it - BUT there is a **critical line** of code that is essential this all works without destroying your Arduino's AREF pin so do check it out before connecting anything.

List of all my videos
(Special thanks to Michael Kurt Vogel for compiling this)
http://bit.ly/YouTubeVideoList-RalphBacon

You can read all this and MORE in my GitHub:
https://github.com/RalphBacon/171-Monitor-Your-Battery

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LINKS to products used in the video
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CJMCU-4599 Si4599 N and P Channel 40V (D -S) **MOSFET Expansion Board** Module about $4 for 3 pieces:
https://www.banggood.com/3pcs-CJMCU-4599-Si4599-N-and-P-Channel-40V-D-S-MOSFET-Expansion-Board-Module-p-1363266.html?p=FQ040729393382015118&utm_campaign=25129675&utm_content=3897

DC-DC **Boost Buck Adjustable** Step Up/Step Down Automatic Converter XL6009 Module about $2.67 (or $5 from UK warehouse):
https://www.banggood.com/DC-DC-Boost-Buck-Adjustable-Step-Up-Step-Down-Automatic-Converter-XL6009-Module-p-1087346.html?p=FQ040729393382015118&utm_campaign=25129675&utm_content=3897

DC-DC 2.5V-15V to 3.3V **Fixed Output** Automatic Buck Boost Step Up Step Down $1.67 each:
https://www.banggood.com/DC-DC-2_5V-15V-to-3_3V-Fixed-Output-Automatic-Buck-Boost-Step-Up-Step-Down-Power-Supply-Module-p-1355827.html?p=FQ040729393382015118&utm_campaign=25129675&utm_content=3897

0.36 Inch **Digital Voltmeter** DC 0V-100V Three Wires 3 Digit Battery Voltage Panel Meter about $2 each or $1 each in a pack fo 10:
https://www.banggood.com/805-Micro-0_36-Inch-Digital-Voltmeter-DC-0V-100V-Three-Wires-3-Digit-Battery-Voltage-Panel-Meter-LED-Display-for-RC-Airplane-Car-Boat-Motorcycle-p-1557653.html?p=FQ040729393382015118&utm_campaign=25129675&utm_content=3897

Wemos **18650 UPS/PSU** as used in the video, about $7 for THREE pieces ($3.68 if bought indivually):
https://www.banggood.com/3Pcs-Wemos-ESP32-ESP32S-18650-Battery-Charge-Shield-V3-Micro-USB-Type-A-USB-0_5A-Test-Charging-Protection-Board-For-Raspberry-Pi-Arduino-p-1448427.html?p=FQ040729393382015118&utm_campaign=25129675&utm_content=3897

Interactive cheat sheet for calculating **potential (resistor) divider** values:
http://www.ohmslawcalculator.com/voltage-divider-calculator

My blog article on what happened to my eye (again):
https://ralphbacon.blog/?p=340

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**YIHUA 938D Portable Hot Tweezers** Mini Soldering Station 110V/220V
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DANIU Heavy Duty **Soldering Solder Iron Tip Cleaner** Steel Wire $3.33 from China, higher price local warehouse
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SMD Components Solder **Practice Module Kit** - all components incl QFP chips
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If you like this video please give it a thumbs up, share it and if you're not already subscribed please consider doing so and joining me on my Arduinite journey

My channel and blog are here:
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https://www.youtube.com/RalphBacon
https://ralphbacon.blog
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Видео #171 External Battery Monitor from your Arduino канала Ralph S Bacon