Ajout charge

Thermostat/Eolienne.md

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+# Wind turbine
+
+To determine the state of charge (SoC) or percentage of fill for your 4 LiFePO₄ (Lithium Iron Phosphate) batteries, you typically use the battery voltage as an indicator. However, LiFePO₄ batteries have a very flat voltage curve, so voltage-based SoC estimation is only accurate at the extremes (fully charged or nearly empty) and less precise in the middle.
+
+Here’s how you can estimate the percentage:
+
+Measure the total voltage of your battery pack (in series, 4S = 4 cells in series).
+Reference a LiFePO₄ voltage-to-SoC table (see below).
+Map the measured voltage to a percentage using the table.
+Typical 4S LiFePO₄ Voltage-to-SoC Table
+
+| Voltage (4S) | SoC (%) |
+| ------------ | ------- |
+| 14.6V	       |    100% |
+| 13.6V	       |     99% |
+| 13.3V	       |     90% |
+| 13.2V	       |     70% |
+| 13.1V	       |     40% |
+| 12.8V	       |     20% |
+| 12.0V	       |     10% |
+| 10.0V	       |      0% |
+
+- **Fully charged (100%)**: 14.4V–14.6V (3.6V–3.65V per cell)
+- **Nominal (50%)**: ~13.2V (3.3V per cell)
+- **Empty (0%)**: 10.0V (2.5V per cell, but avoid discharging this low)
+
+## Steps to Implement
+
+Read the battery voltage using an ADC (Analog-to-Digital Converter) on your ESP32.
+Map the voltage to SoC using the table above (linear interpolation for values in between).
+Display or use the percentage as needed.
+Example (Pseudocode)
+
+```cpp
+float voltage = read_battery_voltage(); // Implement this for your hardware
+float soc = 0;
+
+if (voltage >= 14.6) soc = 100;
+else if (voltage >= 13.6) soc = 99;
+else if (voltage >= 13.3) soc = 90;
+else if (voltage >= 13.2) soc = 70;
+else if (voltage >= 13.1) soc = 40;
+else if (voltage >= 12.8) soc = 20;
+else if (voltage >= 12.0) soc = 10;
+else soc = 0;
+```
+
+> **Notes**
+> For best accuracy, measure voltage after the battery has rested (no load or charging for 30+ minutes).
+> For more precise SoC, use a battery management system (BMS) with coulomb counting.