From 4c78c46cf93d45c2d337205973f272ede30167e8 Mon Sep 17 00:00:00 2001
From: DatanoiseTV <6614616+DatanoiseTV@users.noreply.github.com>
Date: Fri, 8 May 2026 21:57:59 +0200
Subject: [PATCH] power: use BQ25896 ADC for both battery voltage and presence

getBattVoltage on the BQ27220+BQ25896 combo returned the fuel-gauge
reading while isBatteryConnect derived presence from the BQ25896
charger ADC. The two could disagree on a freshly-attached cell before
the fuel gauge had learned: hasBattery would say false but voltage
4.0V, and the upstream PowerFSM would treat the unit as externally
powered. Read voltage from the same source as presence so both views
move together.
---
 src/Power.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/Power.cpp b/src/Power.cpp
index bb9f554be40..53bfd507b82 100644
--- a/src/Power.cpp
+++ b/src/Power.cpp
@@ -1668,9 +1668,14 @@ class LipoCharger : public HasBatteryLevel
     }
 
     /**
-     * The raw voltage of the battery in millivolts, or NAN if unknown
+     * The raw voltage of the battery in millivolts, or 0 if unknown.
+     * Use the BQ25896 charger ADC for both voltage and presence detection so
+     * the two readings can never disagree. The BQ27220 fuel gauge can report
+     * 0 / stale on a freshly-attached cell before its initial learn cycle
+     * finishes, which would make hasBattery=false but voltage=4.0V — the
+     * upstream PowerFSM then thinks the device is externally powered.
      */
-    virtual uint16_t getBattVoltage() override { return bq->getVoltage(); }
+    virtual uint16_t getBattVoltage() override { return PPM->getBattVoltage(); }
 
     /**
      * return true if there is a battery installed in this unit