| layout | default |
|---|---|
| title | ADC Calculator |
Meshtastic devices often do not charge batteries to the true chemistry maximum of 4.20V. Some boards reach a lower maximum (for example 4.15V), which causes the displayed battery percentage or voltage to appear incorrect.
This page provides two ways to correct this behavior:
- 100% Battery Display Calculator — Adjusts the ADC multiplier so the device shows 100% when your battery reaches its actual full voltage, even if that voltage is below 4.20V.
- Accurate Voltage Calibration Calculator — Adjusts the ADC multiplier so the displayed voltage matches a multimeter, giving true electrical accuracy.
Choose the calculator that matches your goal.
Use this calculator if your device never reaches 4.20V but you want the battery indicator to show 100% at the voltage your board actually charges to.
| Device: | |
| Battery Voltage (V): | |
| Current ADC Multiplier: | |
| Calculated New Operative ADC Multiplier: | |
| Calculate |
<script> // Shared device list const DEVICE_DATA = { chatter2: { multiplier: 5.0 }, diy: { multiplier: 1.85 }, "esp32-s3-pico": { multiplier: 3.1 }, "heltec_v1/v2": { multiplier: 3.2 }, heltec_v3: { multiplier: 5.1205, measured: 4.15 }, heltec_wsl_v3: { multiplier: 5.1205 }, heltec_wireless_paper: { multiplier: 2.0 }, heltec_wireless_tracker: { multiplier: 4.9 }, heltec_T114: { multiplier: 4.916, measured: 4.15 }, lora_isp4520: { multiplier: 1.436 }, m5stack_coreink: { multiplier: 5.0 }, "nano-g1-explorer": { multiplier: 2.0 }, "nano-g2-ultra": { multiplier: 2.0 }, "picomputer-s3": { multiplier: 3.1 }, "Promicro(Faketec)": { multiplier: 1.73 }, rak4631: { multiplier: 1.73 }, rpipico: { multiplier: 3.1 }, rpipicow: { multiplier: 3.1 }, "station-g1": { multiplier: 6.45 }, "station-g2": { multiplier: 4.0 }, tlora_v2_1_16: { multiplier: 2.0 }, tlora_v2_1_18: { multiplier: 2.11 }, tlora_t3s3_v1: { multiplier: 2.11 }, "t-deck": { multiplier: 2.11 }, "t-echo": { multiplier: 2.0 } }; // Populate dropdowns function populateDropdown(selectElement, includeMeasured = false) { selectElement.innerHTML = 'Choose'; Object.keys(DEVICE_DATA).forEach(device => { const opt = document.createElement("option"); opt.value = device; opt.textContent = device; if (includeMeasured && DEVICE_DATA[device].measured !== undefined) { opt.setAttribute("data-measured", DEVICE_DATA[device].measured); } selectElement.appendChild(opt); }); } document.addEventListener("DOMContentLoaded", () => { populateDropdown(document.getElementById("deviceSelect")); document.querySelectorAll(".deviceSelect").forEach(drop => populateDropdown(drop, true) ); }); // Calculator 1 function updateAdcMultiplier() { const device = document.getElementById('deviceSelect').value; if (DEVICE_DATA[device]) { document.getElementById('operativeAdcMultiplier').value = DEVICE_DATA[device].multiplier; } } function calculateNewMultiplier() { const batteryVoltage = parseFloat(document.getElementById('batteryVoltage').value); const currentAdcMultiplier = parseFloat(document.getElementById('operativeAdcMultiplier').value); if (isNaN(batteryVoltage) || batteryVoltage <= 0 || isNaN(currentAdcMultiplier)) { alert("Please enter valid numbers."); return; } const targetVoltage = 4.19; const newAdcMultiplier = currentAdcMultiplier * (targetVoltage / batteryVoltage); document.getElementById('newOperativeAdcMultiplier').value = newAdcMultiplier.toFixed(3); } </script>
Use this calculator if you want accurate voltage readings, even if the battery percentage ends up lower than 100%.
<tr>
<td>Max Charge Voltage (Multimeter):</td>
<td><input type="text" class="measuredVoltage" /></td>
</tr>
<tr>
<td>Displayed Voltage (Device):</td>
<td><input type="text" class="displayedVoltage" /></td>
</tr>
<tr>
<td>Current ADC Multiplier:</td>
<td><input type="text" class="manualMultiplier" /></td>
</tr>
<tr>
<td>Adjusted ADC Multiplier:</td>
<td><input type="text" class="adjustedMultiplier" disabled /></td>
</tr>
<tr>
<td></td>
<td>
<button class="button button--outline button--lg cta--button"
onclick="calculateTableMultipliers()">Calculate</button>
</td>
</tr>
| Device: |