July 2019 – Beyondlogic

LTC4040 5V, 2.5A Uninterruptible Power Supply (UPS) with USB-C

July 27, 2019 Craig Peacock 5

Motivation I have had the requirement to back-up small 5V low-powered devices such as a Foscam C1 security camera and a Raspberry PI based LoRaWAN concentrator. Many commonly available 5V Uninterruptible Power Supplies feature a two chip design with a Li-Ion battery charger to charge the back-up battery, and boost converter to step up the battery voltage back up to 5V. Like most of my personal designs, cost was not a primary driver. I was on the search for a elegant, preferably single chip device that was fit for purpose. Lithium Ion batteries can be stressed when left at full …

Review: BQ24650 5A MPPT Solar Controller 3S / 4S Li-Ion, LiFePO4, 12V Lead Acid

July 7, 2019 Craig Peacock 23

Designs based on the Texas Instrument’s bq24650 Synchronous Switch-Mode Battery Charge Controller for Solar Power With Maximum Power Point Tracking are commonplace on Aliexpress, ebay and Amazon. Consumers can purchase assembled PCBs, such as the one pictured above, or complete product enclosed in a relatively nice aluminium extruded housing. According to the silkscreen of versions pictured on-line, different variants are available including: 3S Li-Ion 4S Li-Ion 4S LiFePo4 12V Lead Acid I’m still old-school and wanted to purchase a 12V lead acid version, but couldn’t find any available for sale. And like many similar electronics products from the above mentioned …