# IoT Battery Monitor
## Overview
https://youtu.be/G-mK4szM4Ng
Build an internet connected battery charger and monitor with Feather ESP32-S2 Reverse TFT, CircuitPython, and Adafruit IO.
The on-board MAX17048 LiPoly battery monitor chip reads the batteries voltage and is displayed on the Feather ESP32's built-in color TFT display. Use the on-board button to cycle between icons and text.
The project uses Adafruit IO actions to receive an SMS text or email when the battery is fully charged.
## Enclosure
The 3D printed enclosure snap fits together, and features a tray for holding a 1200mAh battery. The enclosure can swivel forwards and back allowing for an adjustable viewing angle.
Use a JST extension cable to easily swap out batteries without having to unplug from the Feather.
## Parts
### Adafruit ESP32-S2 Reverse TFT Feather
[Adafruit ESP32-S2 Reverse TFT Feather](https://www.adafruit.com/product/5345)
Like Missy Elliot, we like to ["put our [Feather] down, flip it and reverse it"](https://www.youtube.com/watch?v=cjIvu7e6Wq8) and that's exactly what we've done with this new development board. It's basically our ****
Out of Stock
[Buy Now](https://www.adafruit.com/product/5345)
[Related Guides to the Product](https://learn.adafruit.com/products/5345/guides)
### JST-PH Battery Extension Cable - 500mm
[JST-PH Battery Extension Cable - 500mm](https://www.adafruit.com/product/1131)
By popular demand, we now have a handy extension cord for all of our JST PH-terminated battery packs (such as our LiIon/LiPoly and 3xAAA holders). One end has a JST-PH compatible socket, and the other end has a matching plug. Between the two, 500mm of color coded wire. Handy for wearable...
In Stock
[Buy Now](https://www.adafruit.com/product/1131)
[Related Guides to the Product](https://learn.adafruit.com/products/1131/guides)
### Pink and Purple Woven USB A to USB C Cable - 2 meters long
[Pink and Purple Woven USB A to USB C Cable - 2 meters long](https://www.adafruit.com/product/5044)
This cable is not only super-fashionable, with a woven pink and purple Blinka-like pattern, it's also made for USB C for our modernized breakout boards, Feathers and more. [If you want something just like it but for Micro B, we have a B...](https://www.adafruit.com/product/4111)
Out of Stock
[Buy Now](https://www.adafruit.com/product/5044)
[Related Guides to the Product](https://learn.adafruit.com/products/5044/guides)
### 5V 1A (1000mA) USB port power supply - UL Listed
[5V 1A (1000mA) USB port power supply - UL Listed](https://www.adafruit.com/product/501)
Need a USB jack for charging or powering a project, but don't want to lug around a computer? This switching supply gives a clean regulated output at up to 1000mA! 110 or 240 input, so it works in any country. The plugs are "US 2-prong" style so you may need a plug adapter, but...
In Stock
[Buy Now](https://www.adafruit.com/product/501)
[Related Guides to the Product](https://learn.adafruit.com/products/501/guides)
### Battery Options
### Part: 100mAh
quantity: 1
Lithium Ion Polymer Battery - 3.7v 100mAh
[100mAh](https://www.adafruit.com/product/1570)
### Part: 150mAh
quantity: 1
Lithium Ion Polymer Battery - 3.7v 150mAh
[150mAh](https://www.adafruit.com/product/1317)
### Part: 350mAh
quantity: 1
Lithium Ion Polymer Battery - 3.7v 350mAh
[350mAh](https://www.adafruit.com/product/4237)
### Part: 400mAh
quantity: 1
Lithium Ion Polymer Battery - 3.7v 400mAh
[400mAh](https://www.adafruit.com/product/3898)
### Part: 420mAh
quantity: 1
Lithium Ion Polymer Battery - 3.7v 420mAh
[420mAh](https://www.adafruit.com/product/4236)
### Part: 500mAh
quantity: 1
Lithium Ion Polymer Battery - 3.7v 500mAh
[500mAh](https://www.adafruit.com/product/1578)
### Part: 1200mAh
quantity: 1
Lithium Ion Polymer Battery - 3.7v 1200mAh
[1200mAh](https://www.adafruit.com/product/258)
### Part: 2000mAh
quantity: 1
Lithium Ion Polymer Battery - 3.7v 2000mAh
[2000mAh](https://www.adafruit.com/product/2011)
## Hardware
The following hardware is necessary for the case assembly.
- 4x M2.5 x 6mm long machine screws
- 2x M2 x 6mm long FF standoffs
# IoT Battery Monitor
## CAD Files
## 3D Printed Parts
STL files for 3D printing are oriented to print "as-is" on FDM style machines. Parts are designed to 3D print without any support material using PLA filament. Original design source may be downloaded using the links below.
[Download STLs.zip](https://cdn-learn.adafruit.com/assets/assets/000/129/115/original/STLs.zip?1712063612)
[Download CAD source](https://cdn-learn.adafruit.com/assets/assets/000/129/116/original/CAD.zip?1712063719)
## CAD Assembly
The Feather ESP32-S2 Reverse TFT Feather board is secured to the enclosure's back cover using both M2 and M2.5 fasteners. The back cover snap fits onto the front cover. The front cover is secured to the battery tray using M2.5 fastener.
## Build Volume
The parts require a 3D printer with a minimum build volume.
- 68mm (X) x 62mm (Y) x 20mm (Z)
## Design Source Files
The project assembly was designed in Fusion 360. This can be downloaded in different formats like STEP, STL and more.
Electronic components like Adafruit's boards, displays, connectors and more can be downloaded from the [Adafruit CAD parts GitHub Repo](https://github.com/adafruit/Adafruit_CAD_Parts/).
# IoT Battery Monitor
## CircuitPython
[CircuitPython](https://github.com/adafruit/circuitpython) is a derivative of [MicroPython](https://micropython.org) designed to simplify experimentation and education on low-cost microcontrollers. It makes it easier than ever to get prototyping by requiring no upfront desktop software downloads. Simply copy and edit files on the **CIRCUITPY** drive to iterate.
## CircuitPython Quickstart
Follow this step-by-step to quickly get CircuitPython running on your board.
[Download the latest version of CircuitPython for this board via circuitpython.org](https://circuitpython.org/board/adafruit_feather_esp32s2_reverse_tft/)
**Click the link above to download the latest CircuitPython UF2 file.**
Save it wherever is convenient for you.
Plug your board into your computer, using a known-good data-sync cable, directly, or via an adapter if needed.
Double-click the **reset** button (highlighted in red above), and you will see the **RGB status LED(s)** turn green (highlighted in green above). If you see red, try another port, or if you're using an adapter or hub, try without the hub, or different adapter or hub.
For this board, tap reset and wait for the LED to turn purple, and as soon as it turns purple, tap reset again. The second tap needs to happen while the LED is still purple.
If double-clicking doesn't work the first time, try again. Sometimes it can take a few tries to get the rhythm right!
A lot of people end up using charge-only USB cables and it is very frustrating! **Make sure you have a USB cable you know is good for data sync.**
You will see a new disk drive appear called **FTHRS2BOOT**.
Drag the **adafruit\_circuitpython\_etc.uf2** file to **FTHRS2BOOT**.
The **BOOT** drive will disappear and a new disk drive called **CIRCUITPY** will appear.
That's it!
# IoT Battery Monitor
## Create Your settings.toml File
CircuitPython works with WiFi-capable boards to enable you to make projects that have network connectivity. This means working with various passwords and API keys. As of [CircuitPython 8](https://circuitpython.org/downloads), there is support for a **settings.toml** file. This is a file that is stored on your **CIRCUITPY** drive, that contains all of your secret network information, such as your SSID, SSID password and any API keys for IoT services. It is designed to separate your sensitive information from your **code.py** file so you are able to share your code without sharing your credentials.
CircuitPython previously used a **secrets.py** file for this purpose. The **settings.toml** file is quite similar.
Warning: Your **settings.toml** file should be stored in the main directory of your **CIRCUITPY** drive. It should not be in a folder.
## CircuitPython **settings.toml** File
This section will provide a couple of examples of what your **settings.toml** file should look like, specifically for CircuitPython WiFi projects in general.
The most minimal **settings.toml** file must contain your WiFi SSID and password, as that is the minimum required to connect to WiFi. Copy this example, paste it into your **settings.toml** , and update:
- `your_wifi_ssid`
- `your_wifi_password`
```auto
CIRCUITPY_WIFI_SSID = "your_wifi_ssid"
CIRCUITPY_WIFI_PASSWORD = "your_wifi_password"
```
Many CircuitPython network-connected projects on the Adafruit Learn System involve using Adafruit IO. For these projects, you must _also_ include your Adafruit IO username and key. Copy the following example, paste it into your settings.toml file, and update:
- `your_wifi_ssid`
- `your_wifi_password`
- `your_aio_username`
- `your_aio_key`
```auto
CIRCUITPY_WIFI_SSID = "your_wifi_ssid"
CIRCUITPY_WIFI_PASSWORD = "your_wifi_password"
ADAFRUIT_AIO_USERNAME = "your_aio_username"
ADAFRUIT_AIO_KEY = "your_aio_key"
```
Some projects use different variable names for the entries in the **settings.toml** file. For example, a project might use `ADAFRUIT_AIO_ID` in the place of `ADAFRUIT_AIO_USERNAME`. **If you run into connectivity issues, one of the first things to check is that the names in the settings.toml file match the names in the code.**
Warning: Not every project uses the same variable name for each entry in the **settings.toml** file! Always verify it matches the code.
## **settings.toml** File Tips
Here is an example **settings.toml** file.
```auto
# Comments are supported
CIRCUITPY_WIFI_SSID = "guest wifi"
CIRCUITPY_WIFI_PASSWORD = "guessable"
CIRCUITPY_WEB_API_PORT = 80
CIRCUITPY_WEB_API_PASSWORD = "passw0rd"
test_variable = "this is a test"
thumbs_up = "\U0001f44d"
```
In a **settings.toml** file, it's important to keep these factors in mind:
- Strings are wrapped in double quotes; ex: `"your-string-here"`
- Integers are _ **not** _ quoted and may be written in decimal with optional sign (`+1`, `-1`, `1000`) or hexadecimal (`0xabcd`).
- Floats (decimal numbers), octal (`0o567`) and binary (`0b11011`) are not supported.
- Use `\u` escapes for weird characters, `\x` and `\ooo` escapes are not available in **.toml** files
- Example: `\U0001f44d` for 👍 (thumbs up emoji) and `\u20ac` for € (EUR sign)
- Unicode emoji, and non-ASCII characters, stand for themselves as long as you're careful to save in "UTF-8 without BOM" format
When your **settings.toml ** file is ready, you can save it in your text editor with the **.toml** extension.
## Accessing Your **settings.toml** Information in **code.py**
In your **code.py** file, you'll need to `import` the `os` library to access the **settings.toml** file. Your settings are accessed with the `os.getenv()` function. You'll pass your settings entry to the function to import it into the **code.py** file.
```python
import os
print(os.getenv("test_variable"))
```
In the upcoming CircuitPython WiFi examples, you'll see how the **settings.toml ** file is used for connecting to your SSID and accessing your API keys.
# IoT Battery Monitor
## Code the Battery Monitor
Once you've finished setting up your Feather ESP32-S2 Reverse TFT with CircuitPython, you can access the code and necessary libraries by downloading the Project Bundle.
To do this, click on the **Download Project Bundle** button in the window below. It will download to your computer as a zipped folder.
https://github.com/adafruit/Adafruit_Learning_System_Guides/blob/main/Feather_TFT_Battery_Monitor/code.py
## Upload the Code and Libraries to the Feather ESP32-S2 Reverse TFT
After downloading the Project Bundle, plug your Feather ESP32-S2 Reverse TFT into the computer's USB port with a known good USB data+power cable. You should see a new flash drive appear in the computer's File Explorer or Finder (depending on your operating system) called **CIRCUITPY**. Unzip the folder and copy the following items to the Feather's **CIRCUITPY** drive:
- **lib** folder
- **code.py**
- **bat\_bg.bmp**
- **roundedHeavy-26.bdf**
- **roundedHeavy-46.bdf**
Your Feather ESP32-S2 Reverse TFT **CIRCUITPY** drive should look like this after copying the **lib** folder, **.bdf** font files, **.bmp** image file and the **code.py** file.
## Add Your **settings.toml** File
As of CircuitPython 8.0.0, there is support for [Environment Variables](https://docs.circuitpython.org/en/latest/docs/environment.html). Environment variables are stored in a **settings.toml** file. Similar to **secrets.py** , the **settings.toml** file separates your sensitive information from your main **code.py** file. Add your **settings.toml** file as described in the [Create Your settings.toml File page](https://learn.adafruit.com/mars-clock/create-your-settings-toml-file) earlier in this guide. You'll need to include your WiFi network SSID and password as `CIRCUITPY_WIFI_SSID` and `CIRCUITPY_WIFI_PASSWORD` and your Adafruit IO username and key as `AIO_USERNAME` and `AIO_KEY`.
```auto
CIRCUITPY_WIFI_SSID = "YOUR-SSID-HERE"
CIRCUITPY_WIFI_PASSWORD = "YOUR-SSID-PASSWORD-HERE"
AIO_USERNAME = "YOUR-AIO-USERNAME-HERE"
AIO_KEY = "YOUR-AIO-KEY-HERE"
```
## How the CircuitPython Code Works
At the top of the code are some states that are used in the loop. `send_io` enables sending the battery charging data to Adafruit IO. `bat_timer` is the amount of time that the battery monitor is checked and `first_run` and used to note that the code is running for the first time in the loop.
```python
# states
send_io = True
bat_clock = ticks_ms()
bat_timer = 60 * 1000
first_run = True
```
After the states are the **settings.toml** imports and WiFi and Adafruit IO connections.
```python
# settings.toml imports
aio_username = os.getenv('AIO_USERNAME')
aio_key = os.getenv('AIO_KEY')
# connect to wifi
wifi.radio.connect(os.getenv('CIRCUITPY_WIFI_SSID'), os.getenv('CIRCUITPY_WIFI_PASSWORD'))
pool = socketpool.SocketPool(wifi.radio)
requests = adafruit_requests.Session(pool, ssl.create_default_context())
io = IO_HTTP(aio_username, aio_key, requests)
try:
# get feed
battery_feed = io.get_feed("battery-monitor")
except AdafruitIO_RequestError:
# if no feed exists, create one
battery_feed = io.create_new_feed("battery-monitor")
```
If your WiFi access point name or password are incorrect, an error will be generated.
## Graphics
Next are the graphics. There are two display groups: one that includes graphical elements and one that is text only. You can switch between then in the loop depending on your preferences. the **bat\_bg** bitmap file is loaded using the **adafruit\_image** library and its background color is made transparent. **vectorio** shapes are used to show the battery charge graphic and if you are sending data to Adafruit IO.
```python
# default group
group = displayio.Group()
# text only group
textOnly_group = displayio.Group()
board.DISPLAY.root_group = group
# palette for vector graphics
palette = displayio.Palette(5)
palette[0] = 0xFF0000
palette[1] = 0xFFFF00
palette[2] = 0x00FF00
palette[3] = 0x0000FF
palette[4] = 0x000000
# battery rectangle
rect = vectorio.Rectangle(pixel_shader=palette, width=72, height=45, x=140, y=70, color_index = 0)
group.append(rect)
text_bg = vectorio.Rectangle(pixel_shader=palette, width=115, height=70,
x=120, y=60, color_index = 4)
# io indicator circle
circle = vectorio.Circle(pixel_shader=palette, radius=8, x=10, y=10, color_index=3)
textOnly_group.append(circle)
# graphics bitmap
bitmap, palette_bit = adafruit_imageload.load(
"/bat_bg.bmp",
bitmap=displayio.Bitmap,
palette=displayio.Palette,
)
# purple is made transparent
palette_bit.make_transparent(0)
tile_grid = displayio.TileGrid(bitmap, pixel_shader=palette_bit)
group.append(tile_grid)
group.append(circle)
```
Then all of the text attributes are created. There are two font files, one for a smaller font and one for a larger font. The larger font is used for the text only graphics group.
```python
# font for graphics
sm_file = "/roundedHeavy-26.bdf"
sm_font = bitmap_font.load_font(sm_file)
# font for text only
lg_file = "/roundedHeavy-46.bdf"
lg_font = bitmap_font.load_font(lg_file)
volt_text = bitmap_label.Label(sm_font, text=" V", x=150, y=33)
group.append(volt_text)
big_volt_text = bitmap_label.Label(lg_font, text=" V")
big_volt_text.anchor_point = (0.5, 0.0)
big_volt_text.anchored_position = (board.DISPLAY.width / 2, 0)
textOnly_group.append(big_volt_text)
percent_text = bitmap_label.Label(sm_font, text=" %", x=150, y=90)
big_percent_text = bitmap_label.Label(lg_font, text=" %", x=board.DISPLAY.width//2, y=90)
big_percent_text.anchor_point = (0.5, 1.0)
big_percent_text.anchored_position = (board.DISPLAY.width / 2, board.DISPLAY.height - 15)
textOnly_group.append(big_percent_text)
```
## Buttons and I2C
The three buttons on the Feather are setup as **digitalio** inputs. The onboard MAX17048 is instantiated over I2C.
```python
# buttons
button0 = digitalio.DigitalInOut(board.D0)
button0.direction = digitalio.Direction.INPUT
button0.pull = digitalio.Pull.UP
button0_state = False
button1 = digitalio.DigitalInOut(board.D1)
button1.direction = digitalio.Direction.INPUT
button1.pull = digitalio.Pull.DOWN
button1_state = False
button2 = digitalio.DigitalInOut(board.D2)
button2.direction = digitalio.Direction.INPUT
button2.pull = digitalio.Pull.DOWN
button2_state = False
# MAX17048 instantiation
monitor = adafruit_max1704x.MAX17048(board.I2C())
monitor.activity_threshold = 0.01
```
## Colors
There is a simple function called `get_color()` that maps the charge percentage of the battery to a color in a palette. This changes the color of the battery from red to yellow to green as it charges up.
```python
# colors for battery graphic
def get_color(value):
if value < 30:
return 0
elif 30 <= value <= 75:
return 1
else:
return 2
```
## The Loop
In the loop, the buttons control the UI appearance and code functionality. Button D0 toggles sending the battery info to Adafruit IO. Button D1 changes between the text only display group and the graphical group. Button D2 changes between representing the battery charge percentage in text or via the battery graphic.
```python
# toggle sending to adafruit io
if not button0.value and not button0_state:
button0_state = True
send_io = not send_io
if send_io:
circle.color_index = 3
else:
circle.color_index = 4
# toggle graphics or text only
if button1.value and not button1_state:
button1_state = True
if board.DISPLAY.root_group == group:
board.DISPLAY.root_group = textOnly_group
else:
board.DISPLAY.root_group = group
# toggle battery graphic or % text
if button2.value and not button2_state:
button2_state = True
if len(group) > 4:
group.pop()
group.pop()
else:
group.append(text_bg)
group.append(percent_text)
```
## Monitor the Battery
Every minute the MAX17048 is read to check on the battery voltage and charge percentage. The graphics are updated with the data to show on the TFT. If you chose to send the data to IO, the charge percentage is sent to your feed when the battery is fully charged.
```python
# read MAX17048 every 60 seconds
if first_run or ticks_diff(ticks_ms(), bat_clock) >= bat_timer:
first_run = False
battery_volts = monitor.cell_voltage
battery_percent = monitor.cell_percent
print(f"Battery voltage: {battery_volts:.2f} Volts")
print(f"Battery percentage: {battery_percent:.1f} %")
print()
battery_display = map_range(battery_percent, 0, 100, 0, 72)
battery_x = map_range(battery_percent, 0, 100, 210, 140)
# update rectangle to reflect battery charge
rect.width = int(battery_display)
rect.x = int(battery_x)
rect.color_index = get_color(battery_percent)
volt_text.text = f"{battery_volts:.2f} V"
percent_text.text = f"{battery_percent:.1f} %"
big_volt_text.text = f"{battery_volts:.2f} V"
big_percent_text.text = f"{battery_percent:.1f} %"
if battery_percent >= 100 and send_io:
io.send_data(battery_feed["key"], battery_percent)
bat_clock = ticks_add(bat_clock, bat_timer)
```
# IoT Battery Monitor
## Adafruit IO Trigger
## Create New Action
You can receive an email when the battery has been fully charged.
- Go to [https://io.adafruit.com](https://io.adafruit.com)and click on **Actions**
- Click the **New Actions** button.
- Choose **Yes, use Blockly!**
## Reactive Trigger Setup
- Click on the **Triggers** menu, then click on **Reactive**
- Drag the **Reactive** block and snap it to the **Trigger** section in the **Action Root** block
- Click on the **Values** menu, then click on the **Feed** block
- Drag the **Feed** block and snap it to the Feed section in the **Reactive** block. Then, select the **battery-monitor** feed from the dropdown menu
- Click on the **Values** menu, then click the **A number, whole or decimal** block.
- Drag the **A number, whole or decimal** block and snap it to the **Feed or Value** section of the Reactive block. Then, type "100" into the **Feed or Value** block.
- Under the **Operator** section, select " **\>="** from the dropdown menu.
## Action Setup
- Click on Actions menu, then click on **Email**
- Drag the **Email** block and snap it to the **Action** section in the Action Root block.
- Type your preferred text into the **subject** and **body** in the **Email** block.
- Click on Values menu, then click on a **Feed** block.
- Drag the Feed block into the using section in the **Email** block. Then, select **battery-monitor** from the **dropdown** menu
Click the **Save** button when you are finished.
## New Email
You'll now receive an email when the battery is fully charged.
# IoT Battery Monitor
## Assembly
## Installing Feather
Get the 3D printed back cover, hardware screws, and Feather ready to assemble.
Place the Feather over the back cover with the mounting holes lined up and the TFT screen facing up.
Use the following hardware to secure the Feather to the back cover.
- 2x M2 x 6mm long machine screws
- 2x M2.5 x 6mm long machine screws
## Secure Feather
Install and fasten the hardware screws to secure the Feather ESP32-S2 to the 3D printed back cover.
Ensure the Feather has been secured in the correct orientation.
## Connect JST Extension
Plug in the 2-pin JST extension cable to the battery port on-board the Feather ESP32-S2.
## Install Case & Battery Tray
Slide the 3D printed case in between the battery tray's two mounting tabs.
Line up the mounting holes, then insert and fasten two M2.5 x 6mm long machine screws to secure the two parts together.
## Assemble Enclosure
Orient the back cover with the front case and begin to fit the JST extension cable inside the enclosure.
Fit the JST extensions cables socket connector through the notch in the back cover.
Press the front case and back cover together to close them shut.
## Install Battery
Connect the battery to the JST extension cable.
Place the battery into the 3D printed tray.
## Final Build
Congratulations on your build!
The Feather ESP32-S2 will power on immediately after connecting the battery. Plug in a USB cable to your Feather to begin charging the battery.
Allow the Feather to connect to your WiFi and establish a voltage reading. This may take a minute or two to output to the TFT display.
# IoT Battery Monitor
## Usage
## Button D0
Press the **D0 button (top)** to enable sending data to Adafruit IO. The blue circle indicates data is sending to Adafruit IO.
## Button D1
Press the **D1 button (middle)** to toggle between icon view and plain text view.
## Button D2
Press the **D2 button (bottom)** to toggle between the battery icon and battery percentage text.
## USB Charging
Use a 5V 1A power supply and USB-C type cable to charge the battery.
## Featured Products
### Adafruit ESP32-S2 Reverse TFT Feather
[Adafruit ESP32-S2 Reverse TFT Feather](https://www.adafruit.com/product/5345)
Like Missy Elliot, we like to ["put our [Feather] down, flip it and reverse it"](https://www.youtube.com/watch?v=cjIvu7e6Wq8) and that's exactly what we've done with this new development board. It's basically our ****
Out of Stock
[Buy Now](https://www.adafruit.com/product/5345)
[Related Guides to the Product](https://learn.adafruit.com/products/5345/guides)
### JST-PH Battery Extension Cable - 500mm
[JST-PH Battery Extension Cable - 500mm](https://www.adafruit.com/product/1131)
By popular demand, we now have a handy extension cord for all of our JST PH-terminated battery packs (such as our LiIon/LiPoly and 3xAAA holders). One end has a JST-PH compatible socket, and the other end has a matching plug. Between the two, 500mm of color coded wire. Handy for wearable...
In Stock
[Buy Now](https://www.adafruit.com/product/1131)
[Related Guides to the Product](https://learn.adafruit.com/products/1131/guides)
### Lithium Ion Polymer Battery - 3.7v 100mAh
[Lithium Ion Polymer Battery - 3.7v 100mAh](https://www.adafruit.com/product/1570)
Lithium-ion polymer (also known as 'lipo' or 'lipoly') batteries are thin, light, and powerful. The output ranges from 4.2V when completely charged to 3.7V. This battery has a capacity of ~100mAh for a total of about 0.4 Wh. If you need a larger battery,
In Stock
[Buy Now](https://www.adafruit.com/product/1570)
[Related Guides to the Product](https://learn.adafruit.com/products/1570/guides)
### Lithium Ion Polymer Battery with Short Cable - 3.7V 350mAh
[Lithium Ion Polymer Battery with Short Cable - 3.7V 350mAh](https://www.adafruit.com/product/4237)
Lithium-ion polymer (also known as 'lipo' or 'lipoly') batteries are thin, light, and powerful. The output ranges from 4.2V when completely charged to 3.7V. This battery has a capacity of 350mAh for a total of about 1.3 Wh. If you need a larger (or smaller!) battery,
In Stock
[Buy Now](https://www.adafruit.com/product/4237)
[Related Guides to the Product](https://learn.adafruit.com/products/4237/guides)
### Lithium Ion Polymer Battery Ideal For Feathers - 3.7V 400mAh
[Lithium Ion Polymer Battery Ideal For Feathers - 3.7V 400mAh](https://www.adafruit.com/product/3898)
Lithium-ion polymer (also known as 'lipo' or 'lipoly') batteries are thin, light, and powerful. The output ranges from 4.2V when completely charged to 3.7V. This battery has a capacity of **400mAh** for a total of about 1.9 Wh. If you need a larger (or smaller!)...
Out of Stock
[Buy Now](https://www.adafruit.com/product/3898)
[Related Guides to the Product](https://learn.adafruit.com/products/3898/guides)
### Lithium Ion Polymer Battery - 3.7v 500mAh
[Lithium Ion Polymer Battery - 3.7v 500mAh](https://www.adafruit.com/product/1578)
Lithium-ion polymer (also known as 'lipo' or 'lipoly') batteries are thin, light, and powerful. The output ranges from 4.2V when completely charged to 3.7V. This battery has a capacity of 500mAh for a total of about 1.9 Wh. If you need a larger (or smaller!) battery,
Out of Stock
[Buy Now](https://www.adafruit.com/product/1578)
[Related Guides to the Product](https://learn.adafruit.com/products/1578/guides)
### Lithium Ion Polymer Battery - 3.7v 1200mAh
[Lithium Ion Polymer Battery - 3.7v 1200mAh](https://www.adafruit.com/product/258)
Lithium-ion polymer (also known as 'lipo' or 'lipoly') batteries are thin, light, and powerful. The output ranges from 4.2V when completely charged to 3.7V. This battery has a capacity of 1200mAh for a total of about 4.5 Wh. If you need a larger battery,
In Stock
[Buy Now](https://www.adafruit.com/product/258)
[Related Guides to the Product](https://learn.adafruit.com/products/258/guides)
### Lithium Ion Battery - 3.7V 2000mAh
[Lithium Ion Battery - 3.7V 2000mAh](https://www.adafruit.com/product/2011)
Lithium-ion polymer (also known as 'lipo' or 'lipoly') batteries are thin, light, and powerful. The output ranges from 4.2V when completely charged to 3.7V. This battery has a capacity of 2000mAh. If you need a larger (or smaller!) battery,
Out of Stock
[Buy Now](https://www.adafruit.com/product/2011)
[Related Guides to the Product](https://learn.adafruit.com/products/2011/guides)
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