From 79fe1113de83427c67962800ceb51c70be515891 Mon Sep 17 00:00:00 2001
From: Thomas Kolb <cfr34k-git@tkolb.de>
Date: Thu, 1 Jul 2021 21:10:13 +0200
Subject: [PATCH] charge_control: implement voltage transition

---
 src/charge_control.c | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/src/charge_control.c b/src/charge_control.c
index 5f1d6a0..df13794 100644
--- a/src/charge_control.c
+++ b/src/charge_control.c
@@ -136,19 +136,28 @@ static void solar_fsm_update(uint64_t uptime_ms, struct MeasurementResult *meas)
 
 		case CHARGE_TRANSITION:
 			// FIXME: dynamically adjust thresholds
-			charge_state = control_solar_charging(
-					u_bat_float_full,
-					u_bat_float_low,
-					uptime_ms,
-					meas,
-					charge_state,
-					charge_time_in_state);
+			if(charge_time_in_state < INITIAL_TO_FLOAT_TRANSITION_TIME) {
+				fxp_t u_bat_full =
+					fxp_add(u_bat_initial_full,
+						fxp_mult(
+							fxp_sub(u_bat_float_full, u_bat_initial_full),
+							fxp_div(charge_time_in_state, INITIAL_TO_FLOAT_TRANSITION_TIME)));
 
-			// time limit for transition to float charging
-			if(charge_time_in_state > INITIAL_TO_FLOAT_TRANSITION_TIME) {
+				fxp_t u_bat_low = fxp_sub(u_bat_full, u_bat_regulation_corridor);
+
+				charge_state = control_solar_charging(
+						u_bat_full,
+						u_bat_low,
+						uptime_ms,
+						meas,
+						charge_state,
+						charge_time_in_state);
+			} else {
+				// time limit for transition to float charging reached
 				charge_state = CHARGE_FLOAT;
 				break;
 			}
+
 			break;
 
 		case CHARGE_FLOAT: