Track raw battery voltage and filtered battery voltage separately. Estimate remaining battery as min(voltage_estimate, discharged_estimate). Battery voltage LPF time increased.

src/modules/sdlog2/sdlog2.c

@@ -1264,6 +1264,7 @@ int sdlog2_thread_main(int argc, char *argv[])
 				orb_copy(ORB_ID(battery_status), subs.battery_sub, &buf.battery);
 				log_msg.msg_type = LOG_BATT_MSG;
 				log_msg.body.log_BATT.voltage = buf.battery.voltage_v;
+				log_msg.body.log_BATT.voltage_filtered = buf.battery.voltage_filtered_v;
 				log_msg.body.log_BATT.current = buf.battery.current_a;
 				log_msg.body.log_BATT.discharged = buf.battery.discharged_mah;
 				LOGBUFFER_WRITE_AND_COUNT(BATT);

src/modules/sdlog2/sdlog2_messages.h

@@ -249,6 +249,7 @@ struct log_GVSP_s {
 #define LOG_BATT_MSG 20
 struct log_BATT_s {
 	float voltage;
+	float voltage_filtered;
 	float current;
 	float discharged;
 };
@@ -296,7 +297,7 @@ static const struct log_format_s log_formats[] = {
 	LOG_FORMAT(GPSP, "BLLfffbBffff", "AltRel,Lat,Lon,Alt,Yaw,LoiterR,LoiterDir,NavCmd,P1,P2,P3,P4"),
 	LOG_FORMAT(ESC, "HBBBHHHHHHfH", "Counter,NumESC,Conn,N,Ver,Adr,Volt,Amp,RPM,Temp,SetP,SetPRAW"),
 	LOG_FORMAT(GVSP, "fff", "VX,VY,VZ"),
-	LOG_FORMAT(BATT, "fff", "V,C,Discharged"),
+	LOG_FORMAT(BATT, "ffff", "V,VFilt,C,Discharged"),
 	/* system-level messages, ID >= 0x80 */
 	// FMT: don't write format of format message, it's useless
 	LOG_FORMAT(TIME, "Q", "StartTime"),