diff -r dc9281501ca6 -r 542bdc7f6522 www/js/mon_ispindel.js
--- a/www/js/mon_ispindel.js	Sat Aug 19 15:11:35 2023 +0200
+++ b/www/js/mon_ispindel.js	Wed Aug 23 10:30:09 2023 +0200
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (C) 2019-2020
+ * Copyright (C) 2019-2023
  *
  * Michiel Broek <mbroek at mbse dot eu>
  *
@@ -173,10 +173,11 @@
     $('#vg_abv').html('');
    }
 
-   var batt = record.battery - 3.064; // 0% voltage.
+   var battery_max = 4.13;
+   var battery_min = 3.43;
+   var batt = Math.round(((record.battery - battery_min) / (battery_max - battery_min)) * 1000) / 10;
    if (batt < 0)
     batt = 0;
-   batt = Math.round(batt / 1.17875 * 100); // 100% range
    if (batt > 100)
     batt = 100;
    $('#vg_batt').html(batt + '%');