LilyGO T-Echo Lite: Battery Voltage Troubleshoot

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LilyGO T-Echo Lite: Battery Voltage Woes - Let's Fix It!

Hey everyone, let's dive into a frustrating issue many of us face with the LilyGO T-Echo Lite: the dreaded incorrect battery voltage reading. If you're scratching your head because your device is showing a constant 6.00v, even when there's no battery connected, you're in the right place! We're gonna break down the problem, what might be causing it, and hopefully, how to get your device back on track. We'll be using the user's provided information to help troubleshoot and hopefully find a solution, so let's get started!

The Problem: Persistent 6.00V Reading

So, the user has a T-Echo Lite Core (that's the one without the screen, right?) and is using the Meshcore v1.11 companion BLE firmware for it. The kicker? It's always displaying 6.00v, regardless of whether a battery is connected or if it's just plugged into USB-C power. This is super weird, and definitely not what we want. They've tested several batteries: a Makerfocus 3.7v 1100mAh, a generic 3.7v 2000mAh li-ion battery, and a Makerhawk 3.7v 3000mAh battery. Still the same issue. The user is using the iOS app.

This kind of issue makes it hard to gauge how much battery life you have. The voltage reading is crucial for determining how charged the battery is. If the T-Echo Lite always reports 6V, it's essentially useless for keeping track of your battery's status. No one wants to be caught off guard by a dead device. Also, it might create issues with charging the battery properly or even lead to overcharging, which could damage the battery and the device. So, let's figure out what's causing this.

Now, let's talk about the user's attempt at a fix: they tried changing the adcvalue in the techoboard.cpp file to 0.61 or 0.62. This suggests they're aware of a common method for calibrating battery voltage readings on the device. However, changing this value didn't make a difference, indicating something more complex is going on here. The calibration value is used to map the analog reading from the ADC (Analog-to-Digital Converter) to a voltage value. If this mapping isn't right, the battery voltage readings will be inaccurate. Since changing the value didn't fix it, we need to think about other factors. The ADC might not be working correctly or there could be a hardware issue.

Potential Causes and Troubleshooting Steps

Alright, let's get into some possible causes of this issue and what we can do about them. This is where we put on our detective hats and start troubleshooting. Here are a few things to consider:

1. Firmware Issues and Calibration:

  • Firmware Compatibility: Make sure the firmware is actually compatible with your specific T-Echo Lite version. There can be slight variations in hardware, and a mismatched firmware can cause all sorts of problems. Double-check that you're using the right version of the firmware designed for your hardware.
  • Calibration Errors: As the user attempted, calibration is key. However, if the calibration parameters are incorrect or not properly applied, the voltage readings will be wrong. Check the documentation for your firmware. Is there a specific way to calibrate the voltage readings for your battery? There might be a process in the app or firmware to set the correct values. The way the firmware reads the voltage level from the battery might not be set up correctly in the code. It is possible that the voltage reading is not being done correctly and is outputting the wrong voltage. Make sure to check the code.
  • Firmware Update: Sometimes, a newer version of the firmware might fix known bugs or improve voltage reading accuracy. Try updating to the latest version, but again, make sure it's compatible. Since the user mentions using v1.11, check if there's a more recent version available and read the release notes to see if it mentions battery voltage issues.

2. Hardware Problems:

  • ADC Circuit Issues: The ADC (Analog-to-Digital Converter) circuit is responsible for measuring the voltage. If there's a fault in this circuit, it could cause the incorrect readings. Inspect the board for any visible damage to components like resistors or capacitors related to the battery voltage measurement. Look for signs of corrosion or anything that looks out of place. This can be tricky without specialized equipment, but a visual inspection is always a good starting point.
  • Voltage Divider Problems: The battery voltage is usually measured using a voltage divider circuit. If the resistors in this circuit have the wrong values or are damaged, it could lead to incorrect voltage readings. Check the schematic for your T-Echo Lite to identify the resistors involved in the voltage divider and make sure they match the expected values.
  • Power Supply Problems: Although the user is using the USB-C power supply, it is possible for power supply issues to cause inaccurate readings. Check if the device is receiving the correct voltage from the USB-C source. The device could also be drawing too much current, causing the voltage to drop, leading to the readings being inaccurate.

3. Battery Issues:

  • Battery Compatibility: Although the user has tested several batteries, it's worth double-checking that they are compatible with the T-Echo Lite. Make sure the batteries are within the voltage and current specifications for the device. Lithium-ion batteries have different protection circuits, and using a battery without the correct protection can cause voltage readings to be off.
  • Battery Damage: It's unlikely that multiple batteries are faulty, but it's worth checking. A damaged or poorly functioning battery could potentially cause inaccurate voltage readings. A battery that has been over-discharged or overcharged might show unusual readings. Inspect the batteries for physical damage, such as swelling or leaks. It's always a good idea to test a known-good battery, if possible, to eliminate the battery as the issue.

4. Code Review (If You're Comfortable):

  • Check the Code: If you have experience with programming and access to the firmware code, take a look at the section of code responsible for reading the battery voltage. Are there any obvious errors or miscalculations? It's possible that a simple math error is causing the problem. Reviewing the code that handles voltage readings can provide valuable insights into what could be causing the issue. Look for how the ADC values are being converted into voltage readings.
  • Pin Configuration: Ensure that the correct pins are configured for battery voltage measurement. Sometimes, a wrong pin configuration can mess things up. If the wrong pin is being read, it won't give the correct voltage.

Step-by-Step Troubleshooting Guide

Okay, let's walk through some practical steps you can take to troubleshoot this issue:

  1. Double-Check Firmware: Verify that you are using the correct firmware version for your T-Echo Lite hardware. If there's a newer version, try updating it, but make sure it's compatible.
  2. Inspect the Hardware: Carefully examine your device for any physical damage, such as loose connections, burnt components, or any signs of corrosion. The best way to inspect your board is to use a magnifying glass and look for any unusual signs.
  3. Battery Verification: Ensure the batteries you're using are in good condition and compatible with the T-Echo Lite. It might seem repetitive, but it is important to check the physical condition of the batteries. Try a new battery from a reliable source and see if it fixes the problem. If you have access to a multimeter, you can check the voltage of the batteries themselves to verify the voltage.
  4. Calibration Process: Look for specific calibration instructions in your firmware documentation. If there is a calibration process, try running the calibration and see if that fixes the issue. If the user's attempt at changing the ADC value didn't work, there may be another calibration method specific to the firmware.
  5. Code Review (If Possible): If you have the knowledge, review the firmware's code for battery voltage readings. Pay attention to any calculations, pin configurations, or error handling. If you see any oddities, try correcting them to see if it fixes the issue. The code usually involves reading an analog input and converting it to a voltage value. Look at the ADC pin that is being read to ensure that it is the pin that is connected to the battery. Check the ADC value to voltage conversion process.
  6. Seek Community Help: If you're stuck, the community is a great resource! Post on forums like the MeshCore forums, where you'll find other T-Echo Lite users. Explain the problem clearly, including the firmware version, hardware details, and any troubleshooting steps you've already taken. Other users may have encountered the same issue and can offer their solutions.

Conclusion and Next Steps

Having the battery voltage displayed incorrectly is a real bummer, but by going through these steps, we can hopefully nail down what's causing it. Remember, it could be a software issue, a hardware problem, or even a mix of both. Keep in mind that troubleshooting can take time, and it's essential to be patient and methodical. Take it one step at a time, check each possibility, and don't be afraid to reach out for help. Make sure to document your findings as you go, and always back up your code before making changes. Good luck, and happy tinkering! I hope this helps you get your T-Echo Lite working perfectly!