A miscalibrated Power tab is a LiPo killer. Your OSD shows 600mAh consumed; the actual draw is 900mAh. You fly another minute, sag hits, and you’re walking 200 meters through brush to recover a quad with a puffed battery. I calibrate the Power tab on every build before the maiden — it takes 5 minutes and saves hundreds in ruined packs. Here’s the exact procedure.
Voltage Scale: Match Your OSD to Reality
The voltage scale tells Betaflight how to convert the ADC reading from the voltage divider into an actual voltage. Factory defaults are close but never exact — every flight controller’s resistor tolerances introduce a small offset.
Calibration procedure:
1. Plug in a fully charged LiPo (or a bench power supply if you have one)
2. Measure battery voltage at the XT60 connector with a multimeter — this is your reference
3. Open Betaflight Power tab, note the displayed voltage at the top of the screen
4. Calculate: New Voltage Scale = Old Voltage Scale × (Multimeter Voltage / Betaflight Voltage)
5. Enter the calculated value and click Save
6. Verify: the displayed voltage should now match your multimeter within ±0.05V
Example: Betaflight shows 16.5V, multimeter reads 16.8V. Current Scale is 110. New Scale = 110 × (16.8 / 16.5) = 112. Enter 112, Save, verify.
Why the divider matters: The voltage divider consists of two resistors that scale the battery voltage down to the 3.3V range the MCU’s ADC can read. A 10K/1K divider produces a 1:11 ratio. If Betaflight’s “Voltage Meter Source” is set to “Onboard ADC” and the scale is wrong, the divider ratio is slightly off — calibration fixes this without changing hardware.
For 6S (and higher) builds: Verify your FC supports the voltage range. Most F4/F7 FCs use a 10K/1K divider, producing ~2.3V at the ADC pin with a 6S pack (25.2V). This is within the 3.3V ADC range. Some older FCs used a 10K/2K divider that produces only ~1.4V at 6S, reducing resolution.
Current Sensor Calibration: The Setting That Protects Batteries
The current sensor measures amperage draw in real time and integrates it into mAh consumed. If this is wrong, every mAh reading on your OSD is wrong.
Two types of current sensors:
Onboard ADC (analog current sensor): Most modern 4-in-1 ESCs and AIO boards. A shunt resistor produces a small voltage proportional to current. Betaflight reads this via an ADC pin. The “Scale” value converts ADC reading to amps. Calibration requires a charged battery and a known load. The factory scale (usually 100-400 depending on the board) gets you close.
Virtual current sensor: Some older builds lack a physical current sensor. Betaflight can estimate current draw from throttle position and a predefined maximum current value. Accuracy is ±30% at best. If your FC has no current sensor, replace it — virtual current is a stopgap, not a solution.
Calibration procedure for onboard ADC:
1. Fully charge a battery, note its labeled capacity (e.g., 1300mAh)
2. Fly a full pack down to ~3.5V/cell (landing voltage)
3. Note the “mAh Drawn” value from the OSD at landing
4. Recharge the battery, note how many mAh the charger puts back in
5. Calculate: New Scale = Old Scale × (OSD mAh / Charger mAh)
6. Enter, Save, and verify on the next flight
Example: OSD showed 1100mAh drawn. Charger put back 1300mAh. Old Scale = 250. New Scale = 250 × (1100 / 1300) = 211.5 → round to 212. After this correction, your OSD mAh will match actual consumption within ±5%.
Power Tab Parameter Reference
| Setting | Description | Recommended Value | Notes |
|---|---|---|---|
| Voltage Meter Source | Where voltage is read from | Onboard ADC | Use “ESC Sensor” if your ESC provides digital voltage telemetry |
| Current Meter Source | Where current is read from | Onboard ADC | Virtual = no physical sensor; inaccurate |
| Voltage Scale | ADC-to-voltage conversion factor | Board-specific (100-120 typ.) | Calibrate with multimeter |
| Divider Value | Hardware resistor divider ratio | 10 (for 10K/1K divider) | Don’t change unless you modified the hardware |
| Multiplier Value | Secondary voltage calibration (rare) | 1 | Used only for external voltage sensors |
| Current Scale | ADC-to-amps conversion factor | Board-specific (100-400) | Calibrate with charger mAh comparison |
| Current Offset | mA offset at zero current | 0-50mA | Compensates for ADC noise at idle |
| Minimum Cell Voltage | Warning threshold per cell | 3.5V | Trigger “LAND NOW” OSD warning |
| Maximum Cell Voltage | Full charge detection per cell | 4.3V | Used for auto cell-count detection |
| Warning Cell Voltage | Early warning per cell | 3.7V | Trigger “LOW BATTERY” OSD warning |
| Capacity (mAh) | Battery capacity for % calculation | Your pack’s mAh | Set per battery in OSD or CLI |
Cell Count Auto-Detection
Betaflight can auto-detect cell count based on voltage at plug-in. At 4.2V/cell (fully charged):
– 3S: ~12.6V
– 4S: ~16.8V
– 6S: ~25.2V
Set “Maximum Cell Voltage” to 4.3V — slightly above 4.2V — to avoid false detection. If your LiHV packs charge to 4.35V/cell, set Max Cell Voltage to 4.4V.
Manual cell count override: In CLI, set force_battery_cell_count = 6 forces 6S regardless of voltage. Use this if you fly storage-charged packs (3.8V/cell) and auto-detection gets confused.
Common Power Tab Mistakes
Mistake 1: Never calibrating after a new build. Factory current scales are within ±30% at best. I’ve seen “250” scale boards where the correct value was 175. That’s a 43% error on mAh consumed — your OSD shows 1000mAh while you’ve actually pulled 1430mAh. Calibrate before the maiden.
Mistake 2: Using the same calibration for different batteries. Different packs have different internal resistance, which affects voltage sag and actual delivered capacity. Calibrate with your most-used pack, and accept ±5% variance across brands.
Mistake 3: Relying on voltage alarm alone. Voltage sags under load — a 6S pack at 3.5V/cell during hover might read 3.8V/cell after landing. If you land based on voltage, you’re landing too early. mAh consumed is a more accurate fuel gauge; voltage is the backup.
Mistake 4: Setting “Minimum Cell Voltage” too low. At 3.3V/cell under load, you’re damaging the pack. Set minimum to 3.5V/cell under load (3.7V/cell for Li-Ion). Better to land with 20% capacity remaining than buy new packs.
As we detailed in our FPV Current Sensor Calibration guide, proper current calibration is the foundation of battery health monitoring. The Power tab is where that calibration lives.
⚠️ Regulatory Notice: The flight recommendations in this article should be followed in accordance with the latest 2026 drone regulations in your country or region. Always verify local laws regarding flight altitude, no-fly zones, remote ID requirements, and registration before flying. Regulations vary significantly between the FAA (US), EASA (EU), CAA (UK), CAAC (China), and other authorities.
The UAVModel F7 Stack with Precision Current Sensor includes a factory-calibrated 200A hall-effect current sensor accurate to ±2% out of the box — no calibration needed. Available on our flight controller page.