diff --git a/docs/cli_command_availability.md b/docs/cli_command_availability.md
index 997604175..7f78f545a 100644
--- a/docs/cli_command_availability.md
+++ b/docs/cli_command_availability.md
@@ -212,6 +212,8 @@ should use command `0x42`. See [Companion radio binary protocol](companion_proto
 | Bridge | [`get/set bridge.secret`](cli_commands.md#set-the-esp-now-secret) | ESP-NOW is ESP32 only | No | No | No |
 | Board | [`get bootloader.ver`](cli_commands.md#view-the-bootloader-version-nrf52-only) | nRF52 bootloader metadata | Yes | Yes | Yes |
 | Board | [`get pwrmgt.support`; `get pwrmgt.source`; `get pwrmgt.bootreason`; `get pwrmgt.bootmv`](nrf52_power_management.md#cli-commands) | Board power-management implementation | Feature | Feature | Feature |
+| Board | [`get/set pwrmgt.bootlock`; `get/set pwrmgt.cutoff`](cli_commands.md#configure-nrf52-battery-protection) | nRF52 power-management boards with a text CLI | Feature | Feature | Feature |
+| Board | [`get/set battery.profile`; `get/set battery.empty`; `get/set battery.full`; `get/set adc.multiplier`](cli_commands.md#configure-nrf52-battery-protection) | nRF52 power-management boards with a text CLI; relative ADC calibration | Feature | Feature | Feature |
 | Ethernet | [`eth.status`](cli_commands.md#view-ethernet-connection-status) | Ethernet target | Feature | Feature | No |
 | Browser OTA | [`start ota [ap]`; `stop ota`](cli_commands.md#start-or-stop-an-over-the-air-ota-firmware-update) | ESP32 browser uploader | No | No | No |
 | WebConfig | [`start webconfig [ap]`; `stop webconfig`; `get/set webui`](cli_commands.md#browser-configuration-portal-esp32-repeater-and-room-server) | ESP32 WebConfig | No | No | No |
diff --git a/docs/cli_commands.md b/docs/cli_commands.md
index c656364de..cd66480d0 100644
--- a/docs/cli_commands.md
+++ b/docs/cli_commands.md
@@ -1836,7 +1836,13 @@ through binary command `0x42`; this command does not report the Bluetooth PIN.
 
 **Default:** `0.0` (value defined by board)
 
-**Note:** Returns "Error: unsupported by this board" if hardware doesn't support it
+**Note:** On nRF52 boards with power management and a boot-voltage setting,
+this is a saved *relative* calibration: `1.000` keeps the board conversion,
+`1.050` raises all reported battery millivolts by 5%, and `0` resets to
+`1.000`. The allowed range is `0.500`–`1.500`. This affects boot protection,
+running cutoff, telemetry, battery alerts, and percentage. Calibrate against a
+voltmeter before enabling a low cutoff. Other boards retain their existing
+board-specific multiplier behavior, or return unsupported.
 
 ---
 
@@ -4790,6 +4796,70 @@ manufacturer images and the boards still requiring untouched factory dumps.
 
 ---
 
+#### Configure nRF52 battery protection
+**Usage:** `get pwrmgt.bootlock`, `set pwrmgt.bootlock <2500-4200>`
+
+**Usage:** `get pwrmgt.cutoff`, `set pwrmgt.cutoff <off|2500-4200>`
+
+Values are battery millivolts and are saved in internal storage. The boot lock
+defaults to each board's compiled threshold and takes effect on the next boot.
+Boards whose compiled boot lock is disabled also accept `set pwrmgt.bootlock off`.
+The running cutoff
+defaults to `off`; when enabled, three valid low readings at 30-second
+intervals shut the node down. Both checks are bypassed while externally
+powered. A nonzero cutoff cannot exceed the boot lock, and the boot lock
+cannot be disabled while a cutoff is active. A fixed 2000 mV pre-check
+protects flash on boards with a nonzero compiled boot lock before the saved
+setting can be loaded. In the `custom` profile, the lower limit for the boot
+lock and running cutoff is 2000 mV. Firmware warns when any saved voltage is
+below 2500 mV; that experimental range may brown out the board or interrupt
+flash writes. These commands are available on nRF52 boards with
+`NRF52_POWER_MANAGEMENT` and a boot-voltage configuration, in roles with a
+text CLI. The KISS modem has no text CLI for changing these settings.
+
+`battery.profile` selects saved voltage-to-percentage endpoints and protection
+settings. `liion` uses 3000 mV = 0%, 4200 mV = 100%, the board's original boot
+lock, and running cutoff off. `lifepo4` uses 2700 mV = 0%, 3550 mV = 100%,
+2900 mV boot lock, and 2700 mV running cutoff. `custom` starts with the current
+values and allows endpoint overrides. These percentages are simple voltage
+estimates; they are not an accurate state-of-charge measurement under load.
+
+```text
+get battery.profile
+set battery.profile lifepo4
+set battery.profile liion
+set battery.profile custom
+get battery.empty
+set battery.empty 2700
+get battery.full
+set battery.full 3550
+get adc.multiplier
+set adc.multiplier 1.050
+```
+
+The custom empty/full endpoints may be 2000–4200 mV and must be at least 100 mV
+apart. Setting either endpoint automatically selects `custom`; boot lock and
+cutoff remain separately adjustable. `get pwrmgt.bootlock` and
+`get pwrmgt.cutoff` show the values in force after selecting a profile.
+
+For a RAK3401/RAK13302 LiFePO₄ cell:
+
+```text
+set battery.profile lifepo4
+```
+
+The 2.7 V cutoff is a cell-protection choice, not a guarantee of 1 W RF
+output. The [RAK13302 datasheet](https://docs.rakwireless.com/product-categories/wisblock/rak13302/datasheet-vd/)
+specifies 3.0 V minimum at VBAT and lists 5 V / 1 A peak for 30 dBm output.
+Use a cutoff at or above 3.0 V if keeping the radio within its published
+battery-input range matters; verify the actual voltage under transmit load.
+
+The shutdown wake comparator has a separate fixed hardware reference. Changing
+these millivolt settings does not change that wake threshold; a unit may need
+to charge above it or have USB power restored before it wakes.
+
+---
+
 ### Ethernet (when Ethernet support is compiled in)
 
 Ethernet support is available on RAK4631 boards with a RAK13800 (W5100S) Ethernet module. Use the `_ethernet` firmware variants (e.g. `RAK_4631_repeater_ethernet`) to enable this feature.
diff --git a/docs/nrf52_power_management.md b/docs/nrf52_power_management.md
index a747374f7..8f52edb88 100644
--- a/docs/nrf52_power_management.md
+++ b/docs/nrf52_power_management.md
@@ -190,6 +190,13 @@ Power management status can be queried via the CLI:
 | `get pwrmgt.bootreason` | Returns reset and shutdown reason strings                             |
 | `get pwrmgt.bootmv`     | Returns boot voltage in millivolts                                    |
 
+Boards with nRF52 power management and a text CLI also support saved
+`pwrmgt.bootlock`, `pwrmgt.cutoff`, `battery.profile`, `battery.empty`,
+`battery.full`, and relative `adc.multiplier` settings. See the
+[CLI reference](cli_commands.md#configure-nrf52-battery-protection) for their
+ranges, board-specific defaults, and wake behavior. KISS builds honor a saved
+policy if one exists, but have no text CLI for changing it.
+
 On boards without power management enabled, `get pwrmgt.source` and
 `get pwrmgt.bootmv` return:
 ```
@@ -212,11 +219,10 @@ DEBUG: PWRMGT: Boot voltage = 3450 mV (threshold = 3300 mV)
 DEBUG: PWRMGT: LPCOMP wake configured (AIN7, ref=3/8 VDD)
 ```
 
-## Phase 2 (Planned)
+## Further power-management work (Planned)
 
-- Runtime voltage monitoring
-- Voltage state machine (Normal -> Warning -> Critical -> Shutdown)
-- Configurable thresholds
+- A voltage state machine (Normal -> Warning -> Critical -> Shutdown)
+- Configurable wake comparator thresholds
 - Load shedding callbacks for power reduction
 - Deep sleep integration
 - Scheduled wake-up
diff --git a/examples/companion_radio/MyMesh.cpp b/examples/companion_radio/MyMesh.cpp
index 66fece1fa..2aa0a92f4 100644
--- a/examples/companion_radio/MyMesh.cpp
+++ b/examples/companion_radio/MyMesh.cpp
@@ -23,6 +23,9 @@
 #include <helpers/StatsFormatHelper.h>
 #include <helpers/UsbAsciiBinarySwitch.h>
 #include <helpers/UsbLogging.h>
+#if defined(NRF52_POWER_MANAGEMENT)
+#include <helpers/NRF52VoltagePolicy.h>
+#endif
 #if defined(NRF52_PLATFORM)
 #include <helpers/nrf52/RamFallbackFileSystem.h>
 #endif
@@ -9316,6 +9319,11 @@ bool MyMesh::handleCommand(const char* command, uint32_t sender_timestamp,
     while (*command == ' ' || *command == '\t') command++;
   }
 
+#if defined(NRF52_POWER_MANAGEMENT)
+  if (mesh::power::handleVoltagePolicyCommand(command, reply,
+                                               reply_capacity)) return true;
+#endif
+
   if (_radio_profiles.handle(command, reply, reply_capacity, sender_timestamp != 0)) return true;
   if (!strncmp(command, "set tempradio ", 14)) command += 4;
   if (!strcmp(command, "get tempradio")) command += 4;
diff --git a/examples/companion_radio/main.cpp b/examples/companion_radio/main.cpp
index 4090b40f5..5df4cdf3b 100644
--- a/examples/companion_radio/main.cpp
+++ b/examples/companion_radio/main.cpp
@@ -197,6 +197,9 @@ static bool isNetworkTerminalActive();
   #else
     #if defined(EXTRAFS)
       #include "ResilientInternalExtraFS.h"
+      extern "C" struct lfs_config* meshNrf52VoltagePrimaryFsConfig() {
+        return ResilientInternalExtraFS::primaryConfig();
+      }
       extern "C" uint32_t __flash_arduino_end[];
       ResilientInternalExtraFS ExtraFS(0xD4000, 0x19000, 128);
       DataStore store(InternalFS, ExtraFS, rtc_clock);
diff --git a/examples/companion_radio/ui-new/UITask.cpp b/examples/companion_radio/ui-new/UITask.cpp
index ec8776f55..ae8ff0fc0 100644
--- a/examples/companion_radio/ui-new/UITask.cpp
+++ b/examples/companion_radio/ui-new/UITask.cpp
@@ -1,5 +1,8 @@
 #include "UITask.h"
 #include <helpers/TxtDataHelpers.h>
+#if defined(NRF52_POWER_MANAGEMENT)
+#include <helpers/NRF52VoltagePolicy.h>
+#endif
 #include <helpers/ui/BluetoothPairingUiPolicy.h>
 #include <helpers/ui/CompanionHomeLayout.h>
 #include <helpers/ui/CompanionMessageHistory.h>
@@ -484,6 +487,10 @@ class HomeScreen : public UIScreen {
     int batteryPercentage = showBattery
       ? ((batteryMilliVolts - minMilliVolts) * 100) / (maxMilliVolts - minMilliVolts)
       : 0;
+#if defined(NRF52_POWER_MANAGEMENT)
+    batteryPercentage = showBattery
+      ? mesh::power::configuredBatteryPercent(batteryMilliVolts) : 0;
+#endif
     if (batteryPercentage < 0) batteryPercentage = 0; // Clamp to 0%
     if (batteryPercentage > 100) batteryPercentage = 100; // Clamp to 100%
 
diff --git a/examples/companion_radio/ui-orig/UITask.cpp b/examples/companion_radio/ui-orig/UITask.cpp
index b44c38df2..1cb7fab6c 100644
--- a/examples/companion_radio/ui-orig/UITask.cpp
+++ b/examples/companion_radio/ui-orig/UITask.cpp
@@ -4,6 +4,9 @@
 #endif
 #include <Arduino.h>
 #include <helpers/TxtDataHelpers.h>
+#if defined(NRF52_POWER_MANAGEMENT)
+#include <helpers/NRF52VoltagePolicy.h>
+#endif
 #include <helpers/ui/BluetoothPairingUiPolicy.h>
 #include <helpers/ui/RadioProfileDisplayPage.h>
 #include <helpers/ui/RadioProfileSystemStatus.h>
@@ -285,6 +288,9 @@ void UITask::renderBatteryIndicator(uint16_t batteryMilliVolts) {
   const int minMilliVolts = BATT_MIN_MILLIVOLTS;
   const int maxMilliVolts = BATT_MAX_MILLIVOLTS;
   int batteryPercentage = ((batteryMilliVolts - minMilliVolts) * 100) / (maxMilliVolts - minMilliVolts);
+#if defined(NRF52_POWER_MANAGEMENT)
+  batteryPercentage = mesh::power::configuredBatteryPercent(batteryMilliVolts);
+#endif
   if (batteryPercentage < 0) batteryPercentage = 0; // Clamp to 0%
   if (batteryPercentage > 100) batteryPercentage = 100; // Clamp to 100%
 
@@ -495,7 +501,13 @@ void UITask::userLedHandler() {
   }
 
   if (cur_time > next_batt_check) {   // battery reads are not free, keep them rare
-    low_batt = _board->getBattMilliVolts() < LOW_BATT_MILLIVOLTS;
+    uint16_t low_batt_mv = LOW_BATT_MILLIVOLTS;
+#if defined(NRF52_POWER_MANAGEMENT)
+    low_batt_mv = mesh::power::remapBatteryWarningMillivolts(
+        LOW_BATT_MILLIVOLTS, BATT_MIN_MILLIVOLTS, BATT_MAX_MILLIVOLTS,
+        mesh::power::configuredEmpty(), mesh::power::configuredFull());
+#endif
+    low_batt = _board->getBattMilliVolts() < low_batt_mv;
     next_batt_check = cur_time + 60000;
   }
 
diff --git a/examples/simple_repeater/MyMesh.cpp b/examples/simple_repeater/MyMesh.cpp
index 8e1a5ba7e..3a87b3a14 100644
--- a/examples/simple_repeater/MyMesh.cpp
+++ b/examples/simple_repeater/MyMesh.cpp
@@ -7,6 +7,9 @@
 #include <new>       // std::nothrow (heap-allocated flood rule table)
 #include <stdlib.h>  // for qsort()
 #include <helpers/CLICommandUtils.h>
+#if defined(NRF52_POWER_MANAGEMENT)
+#include <helpers/NRF52VoltagePolicy.h>
+#endif
 #include <helpers/ClientACLCLI.h>
 #include <helpers/ClockSyncUtils.h>
 #include <helpers/ClientLoginPersistence.h>
@@ -455,6 +458,9 @@ static bool verifyFloodSettingsWrite(FILESYSTEM* fs, const char* filename,
 }
 
 static uint8_t batteryPercentFromMilliVolts(uint16_t batt_mv) {
+#if defined(NRF52_POWER_MANAGEMENT)
+  return mesh::power::configuredBatteryPercent(batt_mv);
+#else
   const int min_mv = BATT_MIN_MILLIVOLTS;
   const int max_mv = BATT_MAX_MILLIVOLTS;
   if (max_mv <= min_mv) return 100;
@@ -463,6 +469,7 @@ static uint8_t batteryPercentFromMilliVolts(uint16_t batt_mv) {
   if (pct < 0) return 0;
   if (pct > 100) return 100;
   return (uint8_t)pct;
+#endif
 }
 
 static bool parseBatteryAlertPercent(const char* value, uint8_t min_value, uint8_t max_value, uint8_t& result) {
diff --git a/examples/simple_secure_chat/main.cpp b/examples/simple_secure_chat/main.cpp
index 7b47b6061..fe498e310 100644
--- a/examples/simple_secure_chat/main.cpp
+++ b/examples/simple_secure_chat/main.cpp
@@ -21,6 +21,9 @@
 #include <helpers/StaticPoolPacketManager.h>
 #include <helpers/SimpleMeshTables.h>
 #include <helpers/IdentityStore.h>
+#if defined(NRF52_POWER_MANAGEMENT)
+  #include <helpers/NRF52VoltagePolicy.h>
+#endif
 #if defined(ESP32_PLATFORM)
   #include <helpers/ESP32TrueRandom.h>
 #endif
@@ -464,6 +467,14 @@ public:
   }
 
   void handleCommand(const char* command) {
+#if defined(NRF52_POWER_MANAGEMENT)
+    char voltage_reply[160];
+    if (mesh::power::handleVoltagePolicyCommand(command, voltage_reply,
+                                                 sizeof(voltage_reply))) {
+      Serial.println(voltage_reply);
+      return;
+    }
+#endif
     char profile_reply[160];
     if (_radio_profiles.handle(command, profile_reply, sizeof(profile_reply))) {
       Serial.println(profile_reply); return;
@@ -785,6 +796,7 @@ void setup() {
 void loop() {
 #if defined(NRF52_PLATFORM)
   board.feedWatchdog();
+  board.loop();
 #endif
   the_mesh.loop();
   rtc_clock.tick();
diff --git a/src/helpers/CommonCLI.cpp b/src/helpers/CommonCLI.cpp
index 711fd90c1..c7712b680 100644
--- a/src/helpers/CommonCLI.cpp
+++ b/src/helpers/CommonCLI.cpp
@@ -11,6 +11,9 @@
 #include "AdvertDataHelpers.h"
 #include "AlertReporter.h"  // for alertReporterBannedChannelMatch()
 #include "sensors/EnvironmentI2CConfig.h"
+#if defined(NRF52_POWER_MANAGEMENT)
+#include "NRF52VoltagePolicy.h"
+#endif
 #if defined(NRF52_PLATFORM) || defined(STM32_PLATFORM)
 #include "AtomicFileWriter.h"
 #elif defined(ESP32_PLATFORM) || defined(RP2040_PLATFORM)
@@ -3325,6 +3328,9 @@ bool CommonCLI::handleSdCardGetCmd(const char* config, char* reply) {
 
 void CommonCLI::handleSetCmd(uint32_t sender_timestamp, char* command, char* reply) {
   const char* config = &command[4];
+#if defined(NRF52_POWER_MANAGEMENT)
+  if (mesh::power::handleVoltagePolicyCommand(command, reply, 160)) return;
+#endif
   // Infrastructure roles dispatch here rather than through CommonRadioPrefs.
   if (strncmp(config, "path.hash.mode", 14) == 0
       && (config[14] == 0 || config[14] == ' ' || config[14] == '\t')) {
@@ -4631,6 +4637,9 @@ void CommonCLI::handleSetCmd(uint32_t sender_timestamp, char* command, char* rep
 
 void CommonCLI::handleGetCmd(uint32_t sender_timestamp, char* command, char* reply) {
   const char* config = &command[4];
+#if defined(NRF52_POWER_MANAGEMENT)
+  if (mesh::power::handleVoltagePolicyCommand(command, reply, 160)) return;
+#endif
   if (strcmp(config, "password") == 0) {
     if (sender_timestamp == 0) {
       snprintf(reply, 160, "> %s", _prefs->password);
diff --git a/src/helpers/NRF52Board.cpp b/src/helpers/NRF52Board.cpp
index bdd193bbe..c4051febd 100644
--- a/src/helpers/NRF52Board.cpp
+++ b/src/helpers/NRF52Board.cpp
@@ -1,6 +1,7 @@
 #if defined(NRF52_PLATFORM)
 #include "NRF52Board.h"
 #include "PowerManagementUtils.h"
+#include "NRF52VoltagePolicy.h"
 #include "Nrf52BootloaderVersion.h"
 #include "nrf52/SoftDeviceState.h"
 #include <target.h>
@@ -142,6 +143,38 @@ void NRF52Board::begin() {
   #endif
 }
 
+void NRF52Board::loop() {
+#ifdef NRF52_POWER_MANAGEMENT
+  if (!mesh::power::voltagePolicySupported()) return;
+  static uint32_t last_check = 0;
+  static uint8_t low_count = 0;
+  static uint16_t last_threshold = 0;
+  const uint16_t threshold = mesh::power::configuredCutoff();
+  const uint32_t now = millis();
+  if (threshold != last_threshold) {
+    last_threshold = threshold;
+    low_count = 0;
+    last_check = now;
+  }
+  if (threshold == 0 || now - last_check < 30000UL) return;
+  last_check = now;
+  if (isExternalPowered()) {
+    low_count = 0;
+    return;
+  }
+  low_count = mesh::power::nextLowVoltageCount(
+      low_count, getBattMilliVolts(), threshold, false);
+  if (low_count >= 3) initiateShutdown(SHUTDOWN_REASON_LOW_VOLTAGE);
+#endif
+}
+
+#ifdef NRF52_POWER_MANAGEMENT
+uint16_t NRF52Board::calibrateBatteryMillivolts(uint16_t raw_mv) const {
+  return mesh::power::calibratedMillivolts(
+      raw_mv, mesh::power::configuredAdcPermille());
+}
+#endif
+
 #if NRF52_WATCHDOG_TIMEOUT_SECONDS > 0
 static void reloadWatchdogChannels() {
   // Ordinarily only RR0 is enabled. If a bootloader left the watchdog running
@@ -277,20 +310,26 @@ bool NRF52Board::checkBootVoltage(const PowerMgtConfig* config) {
   }
   boot_voltage_mv = mesh::power::medianVoltage(samples[0], samples[1], samples[2]);
   
-  if (config->voltage_bootlock == 0) return true;  // Protection disabled
-
-  // Skip check if externally powered
-  if (isExternalPowered()) {
-    MESH_DEBUG_PRINTLN("PWRMGT: Boot check skipped (external power)");
-    return true;
+  const bool external = isExternalPowered();
+  // Loading the policy still accesses flash. Keep a hard floor ahead of it
+  // for boards whose compiled policy enables boot protection.
+  const uint16_t preflight = config->voltage_bootlock == 0 ? 0
+      : mesh::power::MIN_CUSTOM_MV;
+  if (mesh::power::shouldBootLock(boot_voltage_mv, preflight, external)) {
+    initiateShutdown(SHUTDOWN_REASON_BOOT_PROTECT);
+    return false;
   }
 
-  MESH_DEBUG_PRINTLN("PWRMGT: Boot voltage = %u mV (threshold = %u mV)",
-      boot_voltage_mv, config->voltage_bootlock);
+  mesh::power::loadVoltagePolicyAtBoot(config->voltage_bootlock);
+  boot_voltage_mv = calibrateBatteryMillivolts(boot_voltage_mv);
+  const uint16_t threshold = mesh::power::configuredBootlock();
+  if (threshold == 0 || external) return true;
 
-  // Only trigger shutdown if reading is valid (>1000mV) AND below threshold
-  // This prevents spurious shutdowns on ADC glitches or uninitialized reads
-  if (mesh::power::shouldBootLock(boot_voltage_mv, config->voltage_bootlock, false)) {
+  MESH_DEBUG_PRINTLN("PWRMGT: Boot voltage = %u mV (threshold = %u mV)",
+      boot_voltage_mv, threshold);
+
+  // Only valid ADC readings (>1000 mV) can initiate protective shutdown.
+  if (mesh::power::shouldBootLock(boot_voltage_mv, threshold, false)) {
     MESH_DEBUG_PRINTLN("PWRMGT: Boot voltage too low - entering protective shutdown");
 
     initiateShutdown(SHUTDOWN_REASON_BOOT_PROTECT);
diff --git a/src/helpers/NRF52Board.h b/src/helpers/NRF52Board.h
index 91e2b06c0..92cb3ae3e 100644
--- a/src/helpers/NRF52Board.h
+++ b/src/helpers/NRF52Board.h
@@ -56,6 +56,7 @@ public:
 #endif
       {}
   virtual void begin();
+  void loop() override;
   // Feed the hardware main-loop watchdog. The first call starts it, so normal
   // setup (including filesystem mount and radio initialization) is not timed.
   // A loop blocked forever in SoftDevice-backed flash I/O will stop feeding it
@@ -78,6 +79,11 @@ public:
   bool isUsbDataConnected() override;
   bool isUsbHostConnected() override;
 
+#ifdef NRF52_POWER_MANAGEMENT
+  // Relative to each board's built-in ADC conversion; 1.000 is unchanged.
+  uint16_t calibrateBatteryMillivolts(uint16_t raw_mv) const;
+#endif
+
   void attachDynamicPrefs(KeyValueStore* prefs) { (void)prefs; }  // no-op
 
 #ifdef NRF52_POWER_MANAGEMENT
diff --git a/src/helpers/NRF52VoltagePolicy.cpp b/src/helpers/NRF52VoltagePolicy.cpp
new file mode 100644
index 000000000..77830c153
--- /dev/null
+++ b/src/helpers/NRF52VoltagePolicy.cpp
@@ -0,0 +1,294 @@
+#include "NRF52VoltagePolicy.h"
+
+#if defined(NRF52_PLATFORM) && defined(NRF52_POWER_MANAGEMENT)
+#include <InternalFileSystem.h>
+#include "IdentityStore.h"
+#include "AtomicFileWriter.h"
+#include "PersistentStoreFormat.h"
+#include <stdio.h>
+#include <string.h>
+
+// A Companion using resilient internal ExtraFS has a custom primary LittleFS
+// geometry. Its application supplies that config; ordinary roles use default.
+extern "C" struct lfs_config* meshNrf52VoltagePrimaryFsConfig()
+    __attribute__((weak));
+
+namespace mesh {
+namespace power {
+
+static const char* POLICY_PATH = "/pwrmgt_v1";
+enum Profile : uint8_t { LI_ION = 0, LIFEPO4 = 1, CUSTOM = 2 };
+static bool supported = false;
+static bool boot_off_allowed = false;
+static uint16_t board_bootlock = 0;
+static uint16_t saved_bootlock = 0;
+static uint16_t saved_cutoff = 0;
+static uint16_t empty_mv = 3000;
+static uint16_t full_mv = 4200;
+static uint16_t adc_permille = 1000;
+static Profile profile = LI_ION;
+
+static bool validPercentRange(uint16_t empty, uint16_t full, Profile kind) {
+  return empty >= (kind == CUSTOM ? MIN_CUSTOM_MV : MIN_CONFIGURED_MV)
+      && full <= MAX_CONFIGURED_MV
+      && full >= empty + 100;
+}
+
+static void encode(uint8_t (&data)[20], uint16_t boot, uint16_t low,
+                   uint16_t empty, uint16_t full, uint16_t adc, Profile kind) {
+  data[0] = 'N'; data[1] = 'V'; data[2] = 'P'; data[3] = '2';
+  mesh::storage::writeLE16(data + 4, boot);
+  mesh::storage::writeLE16(data + 6, low);
+  mesh::storage::writeLE16(data + 8, empty);
+  mesh::storage::writeLE16(data + 10, full);
+  mesh::storage::writeLE16(data + 12, adc);
+  data[14] = kind;
+  data[15] = 0;
+  mesh::storage::writeLE32(data + 16,
+      mesh::storage::updateCRC32(0xFFFFFFFFUL, data, 16));
+}
+
+static void readMountedPolicy() {
+  File file(InternalFS);
+  if (!file.open(POLICY_PATH, FILE_O_READ)) return;
+  uint8_t data[20];
+  const size_t length = file.size();
+  const bool complete = (length == 12 || length == sizeof(data))
+      && file.read(data, length) == length;
+  file.close();
+  if (!complete || memcmp(data, "NVP", 3) != 0) return;
+  const bool old_format = length == 12 && data[3] == '1';
+  const bool new_format = length == 20 && data[3] == '2';
+  if ((!old_format && !new_format)
+      || mesh::storage::readLE32(data + length - 4)
+          != mesh::storage::updateCRC32(0xFFFFFFFFUL, data, length - 4)) return;
+  const uint16_t boot = mesh::storage::readLE16(data + 4);
+  const uint16_t low = mesh::storage::readLE16(data + 6);
+  const Profile kind = new_format ? static_cast<Profile>(data[14]) : LI_ION;
+  if (new_format && (data[14] > CUSTOM || data[15] != 0)) return;
+  if (!validThresholdPair(boot, low, boot_off_allowed,
+                          kind == CUSTOM ? MIN_CUSTOM_MV : MIN_CONFIGURED_MV)) return;
+  if (new_format) {
+    const uint16_t empty = mesh::storage::readLE16(data + 8);
+    const uint16_t full = mesh::storage::readLE16(data + 10);
+    const uint16_t adc = mesh::storage::readLE16(data + 12);
+    if (!validPercentRange(empty, full, kind) || adc < 500 || adc > 1500) return;
+    empty_mv = empty;
+    full_mv = full;
+    adc_permille = adc;
+    profile = static_cast<Profile>(data[14]);
+  }
+  saved_bootlock = boot;
+  saved_cutoff = low;
+}
+
+void loadVoltagePolicyAtBoot(uint16_t board_default_mv) {
+  supported = true;
+  board_bootlock = board_default_mv;
+  boot_off_allowed = board_default_mv == 0;
+  saved_bootlock = board_default_mv;
+  saved_cutoff = 0;
+  empty_mv = 3000;
+  full_mv = 4200;
+  adc_permille = 1000;
+  profile = LI_ION;
+
+  struct lfs_config* config = meshNrf52VoltagePrimaryFsConfig
+      ? meshNrf52VoltagePrimaryFsConfig() : nullptr;
+  const bool mounted = config == nullptr
+      ? InternalFS.Adafruit_LittleFS::begin()
+      : InternalFS.Adafruit_LittleFS::begin(config);
+  if (mounted) readMountedPolicy();
+  // Never call InternalFileSystem::begin() here: it auto-formats on failure.
+  // The role's ordinary primary mount retains its existing recovery behavior.
+  InternalFS.end();
+}
+
+bool voltagePolicySupported() { return supported; }
+bool bootlockOffAllowed() { return boot_off_allowed; }
+uint16_t configuredBootlock() { return saved_bootlock; }
+uint16_t configuredCutoff() { return saved_cutoff; }
+uint16_t configuredEmpty() { return empty_mv; }
+uint16_t configuredFull() { return full_mv; }
+uint16_t configuredAdcPermille() { return adc_permille; }
+uint8_t configuredBatteryPercent(uint16_t mv) {
+  return batteryPercent(mv, empty_mv, full_mv);
+}
+
+static bool save(uint16_t boot, uint16_t low, uint16_t empty, uint16_t full,
+                 uint16_t adc, Profile kind) {
+  if (!supported || !validThresholdPair(boot, low, boot_off_allowed,
+                    kind == CUSTOM ? MIN_CUSTOM_MV : MIN_CONFIGURED_MV)
+      || !validPercentRange(empty, full, kind)
+      || adc < 500 || adc > 1500) return false;
+  uint8_t data[20];
+  encode(data, boot, low, empty, full, adc, kind);
+  mesh::AtomicFileWriter writer(&InternalFS, POLICY_PATH);
+  if (!writer || writer.write(data, sizeof(data)) != sizeof(data)
+      || !writer.commit()) return false;
+  saved_bootlock = boot;
+  saved_cutoff = low;
+  empty_mv = empty;
+  full_mv = full;
+  adc_permille = adc;
+  profile = kind;
+  return true;
+}
+
+bool setConfiguredBootlock(uint16_t mv) {
+  return save(mv, saved_cutoff, empty_mv, full_mv, adc_permille, profile);
+}
+bool setConfiguredCutoff(uint16_t mv) {
+  return save(saved_bootlock, mv, empty_mv, full_mv, adc_permille, profile);
+}
+
+static bool matchKey(const char* command, const char* key, bool set) {
+  const char* prefix = set ? "set " : "get ";
+  if (strncmp(command, prefix, 4) != 0) return false;
+  command += 4;
+  const size_t len = strlen(key);
+  return strncmp(command, key, len) == 0
+      && (command[len] == 0 || command[len] == ' ' || command[len] == '\t');
+}
+
+static const char* const KEYS[] = {
+  "pwrmgt.bootlock", "pwrmgt.cutoff", "battery.profile",
+  "battery.empty", "battery.full", "adc.multiplier"
+};
+
+static int commandKey(const char* command, bool set) {
+  if (command == nullptr) return -1;
+  for (unsigned i = 0; i < sizeof(KEYS) / sizeof(KEYS[0]); ++i) {
+    if (matchKey(command, KEYS[i], set)) return (int)i;
+  }
+  return -1;
+}
+
+bool isVoltagePolicyCommand(const char* command) {
+  return commandKey(command, false) >= 0 || commandKey(command, true) >= 0;
+}
+
+// Exact decimal with up to three fractional places. Zero restores factory scale.
+static bool parseAdcPermille(const char* value, uint16_t& out) {
+  if (*value == 0) return false;
+  uint32_t whole = 0, fraction = 0;
+  unsigned digits = 0;
+  bool dot = false;
+  for (const char* p = value; *p; ++p) {
+    if (*p == '.') {
+      if (dot) return false;
+      dot = true;
+    } else if (*p >= '0' && *p <= '9') {
+      if (!dot) {
+        whole = whole * 10 + (*p - '0');
+        if (whole > 1) return false;
+      } else {
+        if (++digits > 3) return false;
+        fraction = fraction * 10 + (*p - '0');
+      }
+    } else return false;
+  }
+  if (dot && digits == 0) return false;
+  while (digits++ < 3) fraction *= 10;
+  const uint32_t result = whole * 1000 + fraction;
+  if (result == 0) { out = 1000; return true; }
+  if (result < 500 || result > 1500) return false;
+  out = (uint16_t)result;
+  return true;
+}
+
+bool handleVoltagePolicyCommand(const char* command, char* reply,
+                                size_t reply_capacity) {
+  if (reply == nullptr || reply_capacity == 0) return false;
+  const bool set = command != nullptr && strncmp(command, "set ", 4) == 0;
+  const int key = commandKey(command, set);
+  if (key < 0) return false;
+  if (!supported) {
+    snprintf(reply, reply_capacity, "Error: voltage policy unsupported");
+    return true;
+  }
+  const char* value = command + 4 + strlen(KEYS[key]);
+  while (*value == ' ' || *value == '\t') ++value;
+
+  if (!set) {
+    if (*value != 0) snprintf(reply, reply_capacity, "Error: get %s", KEYS[key]);
+    else if (key == 0 || key == 1) {
+      const uint16_t mv = key == 0 ? saved_bootlock : saved_cutoff;
+      if (mv == 0) snprintf(reply, reply_capacity, "> off");
+      else snprintf(reply, reply_capacity, "> %u mV", (unsigned)mv);
+    } else if (key == 2) {
+      snprintf(reply, reply_capacity, "> %s",
+               profile == LIFEPO4 ? "lifepo4" : profile == CUSTOM ? "custom" : "liion");
+    } else if (key == 5) {
+      snprintf(reply, reply_capacity, "> %u.%03u",
+               (unsigned)(adc_permille / 1000), (unsigned)(adc_permille % 1000));
+    } else {
+      snprintf(reply, reply_capacity, "> %u mV",
+               (unsigned)(key == 3 ? empty_mv : full_mv));
+    }
+    return true;
+  }
+
+  if (key == 2) {
+    uint16_t boot = saved_bootlock, low = saved_cutoff;
+    uint16_t empty = empty_mv, full = full_mv;
+    Profile next = profile;
+    if (strcmp(value, "lifepo4") == 0) {
+      next = LIFEPO4; boot = 2900; low = 2700; empty = 2700; full = 3550;
+    } else if (strcmp(value, "liion") == 0) {
+      next = LI_ION; boot = board_bootlock; low = 0; empty = 3000; full = 4200;
+    } else if (strcmp(value, "custom") == 0) next = CUSTOM;
+    else {
+      snprintf(reply, reply_capacity, "Error: profile liion|lifepo4|custom");
+      return true;
+    }
+    if (!save(boot, low, empty, full, adc_permille, next))
+      snprintf(reply, reply_capacity, "Error: battery profile could not be saved");
+    else snprintf(reply, reply_capacity, "OK - %s profile saved; reboot for bootlock", value);
+    return true;
+  }
+
+  if (key == 5) {
+    uint16_t adc;
+    if (!parseAdcPermille(value, adc))
+      snprintf(reply, reply_capacity, "Error: multiplier 0 or 0.500-1.500");
+    else if (!save(saved_bootlock, saved_cutoff, empty_mv, full_mv, adc, profile))
+      snprintf(reply, reply_capacity, "Error: multiplier could not be saved");
+    else snprintf(reply, reply_capacity, "OK - ADC multiplier %u.%03u saved",
+                  (unsigned)(adc / 1000), (unsigned)(adc % 1000));
+    return true;
+  }
+
+  uint16_t mv = 0;
+  const uint16_t minimum = (profile == CUSTOM || key == 3 || key == 4)
+      ? MIN_CUSTOM_MV : MIN_CONFIGURED_MV;
+  if (!parseVoltageMillivolts(value, mv,
+                              key == 1 || (key == 0 && boot_off_allowed), minimum)) {
+    snprintf(reply, reply_capacity, "Error: set %s %s%u-4200",
+             KEYS[key], (key == 1 || (key == 0 && boot_off_allowed)) ? "off|" : "",
+             (unsigned)minimum);
+  } else if (key == 0 && saved_cutoff != 0 && (mv == 0 || mv < saved_cutoff)) {
+    snprintf(reply, reply_capacity, "Error: bootlock must be at least cutoff");
+  } else if (key == 1 && mv != 0 && (saved_bootlock == 0 || mv > saved_bootlock)) {
+    snprintf(reply, reply_capacity, "Error: cutoff must not exceed bootlock");
+  } else if ((key == 3 && mv + 100 > full_mv)
+      || (key == 4 && mv < empty_mv + 100)) {
+    snprintf(reply, reply_capacity, "Error: full must exceed empty by 100 mV");
+  } else {
+    const bool ok = save(key == 0 ? mv : saved_bootlock,
+                         key == 1 ? mv : saved_cutoff,
+                         key == 3 ? mv : empty_mv,
+                         key == 4 ? mv : full_mv,
+                         adc_permille, key >= 3 ? CUSTOM : profile);
+    if (!ok) snprintf(reply, reply_capacity, "Error: voltage setting could not be saved");
+    else snprintf(reply, reply_capacity, "OK - %s %s%s%s", KEYS[key], value,
+                  key == 0 ? "; reboot required" : " (saved)",
+                  mv != 0 && mv < MIN_CONFIGURED_MV
+                    ? "; WARNING: below 2500 mV risks brownout/flash failure" : "");
+  }
+  return true;
+}
+
+} // namespace power
+} // namespace mesh
+#endif
diff --git a/src/helpers/NRF52VoltagePolicy.h b/src/helpers/NRF52VoltagePolicy.h
new file mode 100644
index 000000000..a40472422
--- /dev/null
+++ b/src/helpers/NRF52VoltagePolicy.h
@@ -0,0 +1,31 @@
+#pragma once
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "NRF52VoltageRules.h"
+
+#if defined(NRF52_PLATFORM) && defined(NRF52_POWER_MANAGEMENT)
+namespace mesh {
+namespace power {
+
+// Called by checkBootVoltage(). Uses a single non-formatting mount to read the
+// policy, then releases the FS so the application can mount it normally later.
+void loadVoltagePolicyAtBoot(uint16_t board_default_mv);
+bool voltagePolicySupported();
+bool bootlockOffAllowed();
+uint16_t configuredBootlock();
+uint16_t configuredCutoff();
+uint16_t configuredEmpty();
+uint16_t configuredFull();
+uint16_t configuredAdcPermille();
+uint8_t configuredBatteryPercent(uint16_t mv);
+bool setConfiguredBootlock(uint16_t mv);
+bool setConfiguredCutoff(uint16_t mv);
+bool isVoltagePolicyCommand(const char* command);
+bool handleVoltagePolicyCommand(const char* command, char* reply,
+                                size_t reply_capacity);
+
+} // namespace power
+} // namespace mesh
+#endif
diff --git a/src/helpers/NRF52VoltageRules.h b/src/helpers/NRF52VoltageRules.h
new file mode 100644
index 000000000..58c69ef94
--- /dev/null
+++ b/src/helpers/NRF52VoltageRules.h
@@ -0,0 +1,78 @@
+#pragma once
+
+#include <stdint.h>
+#include <string.h>
+
+namespace mesh {
+namespace power {
+
+static const uint16_t MIN_CONFIGURED_MV = 2500;
+static const uint16_t MIN_CUSTOM_MV = 2000;
+static const uint16_t MAX_CONFIGURED_MV = 4200;
+
+inline bool validThresholdPair(uint16_t boot, uint16_t low,
+                               bool boot_off_allowed,
+                               uint16_t minimum_mv = MIN_CONFIGURED_MV) {
+  return (boot == 0 ? boot_off_allowed
+                    : boot >= minimum_mv && boot <= MAX_CONFIGURED_MV)
+      && (low == 0 || (low >= minimum_mv && low <= MAX_CONFIGURED_MV))
+      && (low == 0 || (boot != 0 && low <= boot));
+}
+
+inline bool parseVoltageMillivolts(const char* value, uint16_t& mv,
+                                   bool allow_off,
+                                   uint16_t minimum_mv = MIN_CONFIGURED_MV) {
+  if (value == nullptr) return false;
+  if (allow_off && strcmp(value, "off") == 0) { mv = 0; return true; }
+  if (*value == 0) return false;
+  uint32_t number = 0;
+  for (const char* p = value; *p; ++p) {
+    if (*p < '0' || *p > '9') return false;
+    number = number * 10 + (*p - '0');
+    if (number > MAX_CONFIGURED_MV) return false;
+  }
+  if (number < minimum_mv) return false;
+  mv = (uint16_t)number;
+  return true;
+}
+
+inline uint8_t nextLowVoltageCount(uint8_t previous, uint16_t mv,
+                                   uint16_t cutoff, bool external_power) {
+  if (cutoff == 0 || external_power || mv <= 1000 || mv >= cutoff) return 0;
+  return previous < 3 ? previous + 1 : 3;
+}
+
+inline uint8_t batteryPercent(uint16_t mv, uint16_t empty_mv,
+                              uint16_t full_mv) {
+  if (full_mv <= empty_mv) return 0;
+  if (mv <= empty_mv) return 0;
+  if (mv >= full_mv) return 100;
+  return (uint8_t)(((uint32_t)(mv - empty_mv) * 100U)
+                   / (full_mv - empty_mv));
+}
+
+// Keep a legacy voltage warning at the same fraction of the displayed battery
+// range when the user selects a different chemistry or custom endpoints.
+inline uint16_t remapBatteryWarningMillivolts(uint16_t old_warning,
+                                              uint16_t old_empty,
+                                              uint16_t old_full,
+                                              uint16_t new_empty,
+                                              uint16_t new_full) {
+  if (old_full <= old_empty || new_full <= new_empty) return old_warning;
+  if (old_warning <= old_empty) return new_empty;
+  if (old_warning >= old_full) return new_full;
+  const uint32_t old_span = old_full - old_empty;
+  const uint32_t new_span = new_full - new_empty;
+  return new_empty + (uint16_t)(((uint32_t)(old_warning - old_empty)
+                                 * new_span + old_span / 2U) / old_span);
+}
+
+inline uint16_t calibratedMillivolts(uint16_t raw_mv,
+                                     uint16_t multiplier_permille) {
+  if (raw_mv == 0) return 0;
+  const uint32_t value = ((uint32_t)raw_mv * multiplier_permille + 500U) / 1000U;
+  return value > 65535U ? 65535U : (uint16_t)value;
+}
+
+} // namespace power
+} // namespace mesh
diff --git a/test/README.md b/test/README.md
index fadc45232..fa5dc55e5 100644
--- a/test/README.md
+++ b/test/README.md
@@ -140,6 +140,7 @@ does not reflect the GoogleTest count -- run the built binary directly
 | `test_packet_manager` | `src/Packet.cpp`, `src/Dispatcher.cpp`, `src/helpers/StaticPoolPacketManager.cpp` | truncated-packet rejection, unavailable-radio behavior, scoped RX-delay replacement, queue/CAD scheduling, and staged radio/TX recovery |
 | `test_persistent_store_format` | `src/helpers/PersistentStoreFormat.h` | contact-page headers and CRCs, dirty-page state, stable slot allocation, and bounded resumable legacy migration across power loss |
 | `test_power_management` | `src/helpers/PowerManagementUtils.h` | median filtering of a brownout outlier and valid-reading requirements for the boot lock |
+| `test_nrf52_voltage_rules` | `src/helpers/NRF52VoltageRules.h` | board-default threshold bounds, strict CLI values, and consecutive runtime low-voltage readings |
 | `test_rx_power_saving` | `src/helpers/radiolib/RXPowerSaving.h` | guarded timer/capture bounds across SF5-SF12, bandwidths, TCXO delays and wire preambles; experimental profiles; retuning and strict CLI parsing |
 | `test_noise_floor_estimator` | `src/helpers/radiolib/NoiseFloorEstimator.h` | spaced low percentile, captured off-SF traffic, weighting, contamination limits, persistent rises, resets and clock rollover |
 | `test_region_names` | `src/helpers/RegionNameUtils.h` | canonical public-region markers while preserving distinct private and differently named regions |
diff --git a/test/test_nrf52_voltage_rules/test_nrf52_voltage_rules.cpp b/test/test_nrf52_voltage_rules/test_nrf52_voltage_rules.cpp
new file mode 100644
index 000000000..19e8f8c19
--- /dev/null
+++ b/test/test_nrf52_voltage_rules/test_nrf52_voltage_rules.cpp
@@ -0,0 +1,75 @@
+#include <gtest/gtest.h>
+
+#include <helpers/NRF52VoltageRules.h>
+
+TEST(NRF52VoltageRules, KeepsBoardDefaultsAndRejectsUnsafePairs) {
+  EXPECT_TRUE(mesh::power::validThresholdPair(3300, 0, false));
+  EXPECT_TRUE(mesh::power::validThresholdPair(3000, 2700, false));
+  EXPECT_TRUE(mesh::power::validThresholdPair(0, 0, true));
+  EXPECT_FALSE(mesh::power::validThresholdPair(0, 0, false));
+  EXPECT_FALSE(mesh::power::validThresholdPair(2499, 0, false));
+  EXPECT_FALSE(mesh::power::validThresholdPair(4201, 0, false));
+  EXPECT_FALSE(mesh::power::validThresholdPair(3000, 3100, false));
+  EXPECT_FALSE(mesh::power::validThresholdPair(0, 2700, true));
+  EXPECT_TRUE(mesh::power::validThresholdPair(2000, 2000, false,
+                                             mesh::power::MIN_CUSTOM_MV));
+  EXPECT_FALSE(mesh::power::validThresholdPair(1999, 0, false,
+                                              mesh::power::MIN_CUSTOM_MV));
+}
+
+TEST(NRF52VoltageRules, ParsesCliMillivoltsStrictly) {
+  uint16_t mv = 1234;
+  EXPECT_TRUE(mesh::power::parseVoltageMillivolts("3000", mv, false));
+  EXPECT_EQ(mv, 3000);
+  EXPECT_FALSE(mesh::power::parseVoltageMillivolts("off", mv, false));
+  EXPECT_EQ(mv, 3000);
+  EXPECT_TRUE(mesh::power::parseVoltageMillivolts("off", mv, true));
+  EXPECT_EQ(mv, 0);
+  EXPECT_FALSE(mesh::power::parseVoltageMillivolts("2499", mv, true));
+  EXPECT_FALSE(mesh::power::parseVoltageMillivolts("4201", mv, true));
+  EXPECT_FALSE(mesh::power::parseVoltageMillivolts("3000mV", mv, true));
+  EXPECT_FALSE(mesh::power::parseVoltageMillivolts("3000 ", mv, true));
+  EXPECT_FALSE(mesh::power::parseVoltageMillivolts("", mv, true));
+  EXPECT_TRUE(mesh::power::parseVoltageMillivolts("2000", mv, false,
+                                                 mesh::power::MIN_CUSTOM_MV));
+  EXPECT_FALSE(mesh::power::parseVoltageMillivolts("1999", mv, false,
+                                                  mesh::power::MIN_CUSTOM_MV));
+}
+
+TEST(NRF52VoltageRules, RequiresThreeConsecutiveValidLowReadings) {
+  using mesh::power::nextLowVoltageCount;
+  EXPECT_EQ(nextLowVoltageCount(0, 2690, 2700, false), 1);
+  EXPECT_EQ(nextLowVoltageCount(1, 2650, 2700, false), 2);
+  EXPECT_EQ(nextLowVoltageCount(2, 2600, 2700, false), 3);
+  EXPECT_EQ(nextLowVoltageCount(2, 2700, 2700, false), 0);
+  EXPECT_EQ(nextLowVoltageCount(2, 999, 2700, false), 0);
+  EXPECT_EQ(nextLowVoltageCount(2, 2600, 2700, true), 0);
+  EXPECT_EQ(nextLowVoltageCount(2, 2600, 0, false), 0);
+}
+
+TEST(NRF52VoltageRules, LiFePO4EndpointsAndAdcCalibration) {
+  using mesh::power::batteryPercent;
+  using mesh::power::calibratedMillivolts;
+  EXPECT_EQ(batteryPercent(2700, 2700, 3550), 0);
+  EXPECT_EQ(batteryPercent(3125, 2700, 3550), 50);
+  EXPECT_EQ(batteryPercent(3550, 2700, 3550), 100);
+  EXPECT_EQ(batteryPercent(3700, 2700, 3550), 100);
+  EXPECT_EQ(calibratedMillivolts(3000, 1000), 3000);
+  EXPECT_EQ(calibratedMillivolts(3000, 1050), 3150);
+  EXPECT_EQ(calibratedMillivolts(0, 1500), 0);
+}
+
+TEST(NRF52VoltageRules, RemapsCompanionWarningWithBatteryRange) {
+  using mesh::power::remapBatteryWarningMillivolts;
+  EXPECT_EQ(remapBatteryWarningMillivolts(3500, 3000, 4200,
+                                         3000, 4200), 3500);
+  EXPECT_EQ(remapBatteryWarningMillivolts(3500, 3000, 4200,
+                                         2700, 3550), 3054);
+  EXPECT_EQ(remapBatteryWarningMillivolts(3500, 3000, 4200,
+                                         2000, 3500), 2625);
+}
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}
diff --git a/variants/gat562_30s_mesh_kit/GAT56230SMeshKitBoard.h b/variants/gat562_30s_mesh_kit/GAT56230SMeshKitBoard.h
index 82034c7e7..b18ea8afa 100644
--- a/variants/gat562_30s_mesh_kit/GAT56230SMeshKitBoard.h
+++ b/variants/gat562_30s_mesh_kit/GAT56230SMeshKitBoard.h
@@ -26,7 +26,7 @@ public:
     }
     raw = raw / BATTERY_SAMPLES;
 
-    return (ADC_MULTIPLIER * raw) / 4096;
+    return calibrateBatteryMillivolts((ADC_MULTIPLIER * raw) / 4096);
   }
 
   const char* getManufacturerName() const override {
diff --git a/variants/gat562_mesh_evb_pro/GAT562EVBProBoard.h b/variants/gat562_mesh_evb_pro/GAT562EVBProBoard.h
index a3d738cac..0d2b9f472 100644
--- a/variants/gat562_mesh_evb_pro/GAT562EVBProBoard.h
+++ b/variants/gat562_mesh_evb_pro/GAT562EVBProBoard.h
@@ -26,7 +26,7 @@ public:
     }
     raw = raw / BATTERY_SAMPLES;
 
-    return (ADC_MULTIPLIER * raw) / 4096;
+    return calibrateBatteryMillivolts((ADC_MULTIPLIER * raw) / 4096);
   }
 
   const char* getManufacturerName() const override {
diff --git a/variants/gat562_mesh_tracker_pro/GAT562MeshTrackerProBoard.h b/variants/gat562_mesh_tracker_pro/GAT562MeshTrackerProBoard.h
index f179cdc7f..e694b15f4 100644
--- a/variants/gat562_mesh_tracker_pro/GAT562MeshTrackerProBoard.h
+++ b/variants/gat562_mesh_tracker_pro/GAT562MeshTrackerProBoard.h
@@ -26,7 +26,7 @@ public:
     }
     raw = raw / BATTERY_SAMPLES;
 
-    return (ADC_MULTIPLIER * raw) / 4096;
+    return calibrateBatteryMillivolts((ADC_MULTIPLIER * raw) / 4096);
   }
 
   const char* getManufacturerName() const override {
diff --git a/variants/gat562_mesh_watch13/GAT56MeshWatch13Board.h b/variants/gat562_mesh_watch13/GAT56MeshWatch13Board.h
index d8fcb2bb7..31ad7c809 100644
--- a/variants/gat562_mesh_watch13/GAT56MeshWatch13Board.h
+++ b/variants/gat562_mesh_watch13/GAT56MeshWatch13Board.h
@@ -26,7 +26,7 @@ public:
     }
     raw = raw / BATTERY_SAMPLES;
 
-    return (ADC_MULTIPLIER * raw) / 4096;
+    return calibrateBatteryMillivolts((ADC_MULTIPLIER * raw) / 4096);
   }
 
   const char* getManufacturerName() const override {
diff --git a/variants/heltec_t096/T096Board.cpp b/variants/heltec_t096/T096Board.cpp
index 2499dcd13..f46481f88 100644
--- a/variants/heltec_t096/T096Board.cpp
+++ b/variants/heltec_t096/T096Board.cpp
@@ -76,7 +76,7 @@ uint16_t T096Board::getBattMilliVolts() {
     adcvalue = analogRead(PIN_VBAT_READ);
     digitalWrite(PIN_BAT_CTL, 0);
 
-    return (uint16_t)((float)adcvalue * MV_LSB * 4.9);
+    return calibrateBatteryMillivolts((uint16_t)((float)adcvalue * MV_LSB * 4.9));
 }
 void T096Board::variant_shutdown() {
  nrf_gpio_cfg_default(PIN_VEXT_EN);
diff --git a/variants/heltec_t1/T1Board.cpp b/variants/heltec_t1/T1Board.cpp
index a54b8eae4..7cfd21249 100644
--- a/variants/heltec_t1/T1Board.cpp
+++ b/variants/heltec_t1/T1Board.cpp
@@ -77,7 +77,7 @@ uint16_t T1Board::getBattMilliVolts() {
   int adcvalue = analogRead(PIN_VBAT_READ);
   digitalWrite(PIN_BAT_CTL, !ADC_CTRL_ENABLED);
 
-  return (uint16_t)((float)adcvalue * MV_LSB * ADC_MULTIPLIER);
+  return calibrateBatteryMillivolts((uint16_t)((float)adcvalue * MV_LSB * ADC_MULTIPLIER));
 }
 
 void T1Board::variant_shutdown() {
diff --git a/variants/heltec_t114/T114Board.h b/variants/heltec_t114/T114Board.h
index 6d7664cbd..e3ea410e0 100644
--- a/variants/heltec_t114/T114Board.h
+++ b/variants/heltec_t114/T114Board.h
@@ -39,7 +39,7 @@ public:
     adcvalue = analogRead(PIN_VBAT_READ);
     digitalWrite(6, 0);
 
-    return (uint16_t)((float)adcvalue * MV_LSB * 4.9);
+    return calibrateBatteryMillivolts((uint16_t)((float)adcvalue * MV_LSB * 4.9));
   }
 
   const char* getManufacturerName() const override {
diff --git a/variants/heltec_tower_v2/HeltecTowerV2Board.cpp b/variants/heltec_tower_v2/HeltecTowerV2Board.cpp
index 16a7bd94e..61de14c48 100644
--- a/variants/heltec_tower_v2/HeltecTowerV2Board.cpp
+++ b/variants/heltec_tower_v2/HeltecTowerV2Board.cpp
@@ -81,7 +81,7 @@ uint16_t HeltecTowerV2Board::getBattMilliVolts() {
   int adcvalue = analogRead(PIN_VBAT_READ);
   digitalWrite(PIN_BAT_CTL, LOW);
 
-  return (uint16_t)((float)adcvalue * MV_LSB * ADC_MULTIPLIER);
+  return calibrateBatteryMillivolts((uint16_t)((float)adcvalue * MV_LSB * ADC_MULTIPLIER));
 }
 
 const char* HeltecTowerV2Board::getManufacturerName() const {
diff --git a/variants/muzi_base/MuziBaseBoard.h b/variants/muzi_base/MuziBaseBoard.h
index a5a4abbe2..02340ce09 100644
--- a/variants/muzi_base/MuziBaseBoard.h
+++ b/variants/muzi_base/MuziBaseBoard.h
@@ -39,7 +39,7 @@ public:
     raw = raw / BATTERY_SAMPLES;
 
     // ADC_MULTIPLIER is the voltage divider ratio
-    return (raw * ADC_MULTIPLIER * AREF_VOLTAGE) / 4.096;
+    return calibrateBatteryMillivolts((raw * ADC_MULTIPLIER * AREF_VOLTAGE) / 4.096);
   }
 
   const char* getManufacturerName() const override {
diff --git a/variants/muziworks_r1_neo/R1NeoBoard.h b/variants/muziworks_r1_neo/R1NeoBoard.h
index fa49a1843..ecd75b717 100644
--- a/variants/muziworks_r1_neo/R1NeoBoard.h
+++ b/variants/muziworks_r1_neo/R1NeoBoard.h
@@ -54,7 +54,7 @@ public:
     }
     raw = raw / BATTERY_SAMPLES;
 
-    return (ADC_MULTIPLIER * raw) / 4096;
+    return calibrateBatteryMillivolts((ADC_MULTIPLIER * raw) / 4096);
   }
 
   const char* getManufacturerName() const override {
diff --git a/variants/rak3401/RAK3401Board.h b/variants/rak3401/RAK3401Board.h
index 940a265f4..9c2be9b5f 100644
--- a/variants/rak3401/RAK3401Board.h
+++ b/variants/rak3401/RAK3401Board.h
@@ -39,7 +39,7 @@ public:
     }
     raw = raw / BATTERY_SAMPLES;
 
-    return (ADC_MULTIPLIER * raw) / 4096;
+    return calibrateBatteryMillivolts((ADC_MULTIPLIER * raw) / 4096);
   }
 
   const char* getManufacturerName() const override {
diff --git a/variants/rak4631/RAK4631Board.h b/variants/rak4631/RAK4631Board.h
index 7e67165b1..6548f913d 100644
--- a/variants/rak4631/RAK4631Board.h
+++ b/variants/rak4631/RAK4631Board.h
@@ -29,7 +29,7 @@ public:
     }
     raw = raw / BATTERY_SAMPLES;
 
-    return (ADC_MULTIPLIER * raw) / 4096;
+    return calibrateBatteryMillivolts((ADC_MULTIPLIER * raw) / 4096);
   }
 
   const char* getManufacturerName() const override {
diff --git a/variants/sensecap_solar/SenseCapSolarBoard.h b/variants/sensecap_solar/SenseCapSolarBoard.h
index 8bf65c907..0fc2c5e5c 100644
--- a/variants/sensecap_solar/SenseCapSolarBoard.h
+++ b/variants/sensecap_solar/SenseCapSolarBoard.h
@@ -30,7 +30,7 @@ public:
     analogReference(AR_INTERNAL_3_0);
     delay(10);
     adcvalue = analogRead(BATTERY_PIN);
-    return (adcvalue * ADC_MULTIPLIER * AREF_VOLTAGE) / 4.096;
+    return calibrateBatteryMillivolts((adcvalue * ADC_MULTIPLIER * AREF_VOLTAGE) / 4.096);
   }
 
   const char* getManufacturerName() const override {
diff --git a/variants/xiao_nrf52/XiaoNrf52Board.cpp b/variants/xiao_nrf52/XiaoNrf52Board.cpp
index 42ee6a87f..96c000606 100644
--- a/variants/xiao_nrf52/XiaoNrf52Board.cpp
+++ b/variants/xiao_nrf52/XiaoNrf52Board.cpp
@@ -68,7 +68,7 @@ uint16_t XiaoNrf52Board::getBattMilliVolts() {
   // VBAT_ENABLE must be LOW to read battery voltage
   digitalWrite(VBAT_ENABLE, LOW);
   int adcvalue = analogRead(PIN_VBAT);
-  return (adcvalue * ADC_MULTIPLIER * AREF_VOLTAGE) / 4.096;
+  return calibrateBatteryMillivolts((adcvalue * ADC_MULTIPLIER * AREF_VOLTAGE) / 4.096);
 }
 
-#endif
\ No newline at end of file
+#endif