Introducing the Open UpCell - a versatile power solution to one of the most common challenges faced by makers and developers: powering their projects. We understand that integrating power sources can be a time-consuming and often frustrating task. Open UpCell aims to make this process seamless, allowing you to focus on your innovative ideas rather than the intricacies of power connections.

Use Cases

One of the biggest areas we currently use Open UpCell today is to get reliable multi-day, multi-voltage, high current power for our projects.

Open UpCell is capable of simultaneously outputing the following voltages: | Source | Voltage (Volts) | Current (Amps) | | —- | —- | —- | | Protected Battery | 3 - 4.2 V | 3.1 A | | 5 V Boost Mode | 5 V | 3.1 A | | 3.3 V LDO | 3.3 V | 1.5 A |

This allowed us to power a GSM Modem (input voltage 3.7 V to 4.2 V), a GPS Module (input voltage 3.3 V), and a ESP32 Dev Board (input voltage 5 V) for 3 days using a 21700 6000mAh battery, without needing multiple batteries, LDOs, or Buck-Boost Converters.

We also use it in our offices to provide backup power to our routers, allowing us to stay connected even when the power goes out. Backup power to your critical network devices like routers, SD-WANs and wireless modems is a must have out in the field, and UpCell makes it easy to do so, even without active Solar Charging.

Below we used Open UpCell to power a 12 V 1 A router, by connecting the output of UpCell to a Boost Converter.

Open UpCell can be used to power your Raspberry Pi, and can be recharged using a USB-C PD charger.

Below we used Open UpCell to power a Raspberry Pi 3B for 2 hours. The Pi was running a python script that was logging data from a temperature sensor every 5 seconds.

Open UpCell will automatically switch between external power and battery power, without any interruption to the Pi, which means it can also be used as a UPS, allowing you to safely shutdown your Pi when the power goes out.

This can be achieved with the help of a simple python script that monitors the charging state of the battery over I2C and triggers a shutdown when the battery is low.

At the end of the 2 hours, the battery was at 3.4 V, and the Pi was still running, albeit with a low voltage warning.

Open UpCell is an excellent power backup device for most hobby builds, and is compact enough to work with wearables and other small form factor projects without any compromise on functionality.

Features & Specifications

• Battery Size Compatibility: Open UpCell comes in two variants, accommodating either 18650 or 21700 cells.
• Battery Type Compatibility: It is compatible with various Li-ion batteries, Li-Po batteries, LiFeO4, or any single-cell battery of similar chemistry.
• Protection Against Fully Discharged Battery: Open UpCell ensures safety by not charging completely discharged cells, preventing potential harm.
• Short Circuit Protection: It can detect high currents across the 5V output and ground, automatically shutting off the output. A manual reset is required in such cases.
• Input Over-Voltage Protection: Prevents overcharging by monitoring battery voltage and charging current, halting the process if predefined thresholds are exceeded. This safeguards the battery and device.
• Input Over-Current Protection: Safeguards the battery and circuitry from excessive charging current. Charging halts if the current exceeds predefined thresholds, reducing the risk of overheating.
• Overcharge Protection: Prevents the battery from being charged beyond its capacity, safeguarding it from damage, reduced lifespan, or explosion.
• Fused Input: Protects the device from voltage spikes and surges, ensuring reliable operation in various environments.
• USB Type-C for Charging: Utilizes the increasingly popular and versatile Type-C connectors for fast and efficient charging. It also supports USB Power Delivery (PD) protocol for flexible and efficient power delivery.
• 5 V, 9 V, or 12 V USB PD / Fast Charging: Adapts to various output voltages and currents, enhancing charging speed and compatibility with different devices.
• On-board Groove Connector: Simplifies the prototyping process, allowing you to plug and play with Groove sensors and modules without the need for soldering.
• On-board STEMMA-QT Connector: Expands compatibility further, enabling plug-and-play functionality with a wide variety of boards, sensors, and modules that use STEMMA-QT connectors.
• On-board 2 JST-2 Pin LiPo Battery Connector: Provides a convenient way to connect LiPo batteries, simplifying battery replacement without soldering.
• Trickle Charging: Maintains the battery's charge and prevents rapid discharge, extending battery life and capacity.
• Easily Switchable Between 3.3 V and 5 V: You can effortlessly adjust the output voltage between 3.3 V and 5 V using the on-board 3-pin male connector.
• On-board NTC Thermistor: Ensures safe and efficient battery charging by monitoring the temperature of the battery and adjusting charging parameters accordingly.
• Charge Status LED: An orange LED indicates the charging status, whether the cell is fully charged, in the charging process, or facing a potential fault.
• Power Status LED: An on-board red SMD LED indicates whether Open UpCell is powered on.
• 15-pin Male Connector: Provides access to various pins of the main IC (BQ25895), allowing for experimentation.

Open UpCell is versatile, user-friendly, and designed to streamline your project’s power management. Whether you’re a maker, developer, or tinkerer, it simplifies the complexities of powering your creations.

Comparisons

Adapter boards

We also created the following add-ons for Open UpCell to make it even more versatile and easy to use. You can download the models and Gerber files for these add-ons from our GitHub repository linked below.

1. Raspberry Pi to Groove Adapter

{open-upcell-pi-groove-adapter | small} 2. Raspberry Pi to STEMMA-QT Adapter

{open-upcell-pi-stemmaqt-adapter | small} 3. Multipin Adapter

Support and Documentation

• Datasheet of BQ25895 IC, onboard voltage controller
• Hackaday.io project log
• OSHWA certification
• GitHub: Hardware (coming soon!)

Fulfillment & Logistics

After production, testing, and packaging, we will ship products to Crowd Supply’s fulfillment partner, Mouser Electronics, who will handle distribution to backers worldwide. You can learn more about Crowd Supply’s fulfillment services in the Ordering, Paying, and Shipping guide.

Risks & Challenges

Open UpCell relies on only a single critical active component, the heart of the product - Texas Instrument’s BQ25895. As of October 2023, this IC is available in the 100,000s from TI themselves, and is also well stocked (2000+ units) on Mouser and Digi-Key. The rest of the components are passives, (or simple to swap out, such as the 3.3 V LDO), making this product virtually risk-free from potential chip shortages.