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Ensuring power safety for Open UpCell users has been our top priority. We’ve undertaken a comprehensive testing phase, implementing safety measures at every stage of development. Here’s a glimpse of some of the tests we conducted:
Non-Compliant USB Power Input: We subjected the device to a non-compliant USB power input scenario, connecting an external 12V supply via a modified USB cable with no data pins. The result? The device continued to charge safely, undisturbed.
Output Short Circuit / Overcurrent: We rigorously tested for output short circuits and overcurrent situations. This involved individually shorting the 5V, 3.3V, and VSYS pins to ground and connecting various resistors to the output. The outcome? The output was swiftly cut off with no "magic smoke", even when using a 0.5-ohm resistor!
Over Discharge: We evaluated the device’s response to over-discharge conditions, testing it with different batteries under varying voltages. The UpCell impressively cut off the output at levels close to our preset limits.
Non-Charging of Dead Batteries: We tested the device with batteries at dangerously low voltages, including a 18650 at 1.2V and a Li-ion flatpack cell at 0.8V. As expected, the charging status LED indicated a charge error, and the batteries drew no current from UpCell.
Our journey has been marked by continuous learning. Every test, even an early one that led to some magic smoke due to reverse battery connection, has contributed to our knowledge and improvements.
The incident involving reverse voltage emphasized the need for reverse voltage protection. We promptly incorporated this crucial feature, further elevating the safety of our boards.
This incident served as a strong motivator, driving us to make UpCell one of the safest products in its category. We’ve left no stone unturned, implementing safety measures for all conceivable scenarios:
With UpCell, using lithium batteries for your projects is now safer than ever. We extend our heartfelt thanks to our backers for fully funding this project. We can’t wait to share UpCell with you and the entire community!