2 files changed, 7 insertions, 5 deletions

diff --git a/firmware/powermgmt.c b/firmware/powermgmt.c
index bcf0659585..62bc5d3814 100644
--- a/firmware/powermgmt.c
+++ b/firmware/powermgmt.c
@@ -466,10 +466,11 @@ static void power_thread(void)
                         snprintf(power_message, POWER_MESSAGE_LEN, "chg pause %d min", charge_pause);
                     } else {
                         /* calculate max charge time depending on current battery level */
-                        /* take 20% more because battery level is not linear */
-                        charge_max_time_now = CHARGE_MAX_TIME * (100 + 30 - battery_level()) / 100;
-                        if (charge_max_time_now > CHARGE_MAX_TIME) {
-                          charge_max_time_now = CHARGE_MAX_TIME;
+                        /* take 35% more because battery level is not linear */
+                        i = CHARGE_MAX_TIME_1500 * BATTERY_CAPACITY / 1500;
+                        charge_max_time_now = i * (100 + 35 - battery_level()) / 100;
+                        if (charge_max_time_now > i) {
+                          charge_max_time_now = i;
                         }
                         snprintf(power_message, POWER_MESSAGE_LEN, "ChgAt %d%% max %dm", battery_level(), charge_max_time_now);
 
diff --git a/firmware/powermgmt.h b/firmware/powermgmt.h
index f2f3a0ef94..5e828e265f 100644
--- a/firmware/powermgmt.h
+++ b/firmware/powermgmt.h
@@ -39,7 +39,8 @@
 
 #ifdef HAVE_CHARGE_CTRL
 #define POWER_MESSAGE_LEN 32     /* power thread status message */
-#define CHARGE_MAX_TIME   8*60   /* minutes: maximum charging time */
+#define CHARGE_MAX_TIME_1500 450 /* minutes: maximum charging time for 1500 mAh batteries */
+                                 /* actual max time depends also on BATTERY_CAPACITY! */
 #define CHARGE_MIN_TIME   10     /* minutes: minimum charging time */
 #define CHARGE_RESTART_HI 85     /* %: when to restart charging in 'charge' mode */
                                  /* attention: if set too high, normal charging is started in trickle mode */