MyOldPCS

For my DIY battery build (4S LiFePO4 40Ah), I decided to add a “smart” monitoring system. Sure, I could have just bought an off-the-shelf Smart BMS with Bluetooth or Wi-Fi, but that’s not my style. I want to understand the entire process and build something of my own. First and foremost, I need to track the charge and discharge current. Based on this data, I’ll later be able to develop an algorithm for accurate State of Charge calculation. First and foremost, I need to track the charge and discharge current. Based on this data, I will eventually be able to develop an algorithm to calculate the State of Charge (SoC) . I’m not going to claim that this will be a high-precision instrument - it’s not. It is more of a ‘rough gauge’ to help me stay oriented: to see if everything is fine or if the power consumption has become abnormally high and something has gone wrong. To measure the current, we’ll use the INA226 module. Typically, these boards come with a 0.1 Ohm (100 mOhm) shunt resist...

In recent months, I’ve noticed that my file server has been shutting down frequently. The primary reason is that the UPS (LX2UPS) charge is no longer sufficient. It is likely that the 18650 cells have degraded, and frequent power outages have only worsened the situation. Therefore, I decided to investigate how this can be fixed. My server is built on an Orange Pi Zero 3 and a 2.5” SATA HDD in an external USB enclosure. To start, I decided to measure the actual power consumption. Test #1: Power Consumption Without Drives In this test, I will check the power consumption of the Orange Pi Zero board alone, without any peripherals. I am conducting the measurements using a USB power meter, which allows me to monitor instantaneous current and total power consumption in milliwatts (mW). First stage: 30 minutes of operation with Wi-Fi and Ethernet enabled, with no background processes. Measurements showed a consumption of 820 mWh . Second stage: The same conditions, but the Wi-Fi and Bl...

If you look at the MT3608 datasheet, you’ll notice that pin 4 is the Enable pin, designed to toggle the chip’s operation. A high level signal enables the chip, while a low level signal disables the voltage boosting. In the latter case, the output voltage will simply match the input voltage of the module. As we can see, EN is connected to the adjacent pin (5) of the IC, which is our input positive VIN . Therefore, to control the EN input, this trace must be cut. Initially, I wanted to use a rotary tool for this, but even the smallest burr turned out to be too large.   So, there was nothing left to do but cut the trace with a scalpel.   I’m doing all of this under a microscope, and in 15 seconds, the trace is gone.   Now it’s time to put everything together. I want to use the RCWL-0516 module as the control signal source. This module is a microwave motion sensor. As for the load, let’s use a 12V fan. We’ll supply 5V to the input from a regulated power supply. ...