[Galaxy S 4 i9505 Original Android Development] Chelonee:
I use Lux Auto brightness for that, works pretty well. :D

But yes,Display is always the greatest battery drainer. I also lowered max frequency to 1,674, I'm not sure if that really makes a difference, but my device is still smooth and lagfree, so I keep it that way for now.

Here are my adjustments:

stweaks_boot_control=yes

scaling_max_freq_all_cpus=1674000

scaling_min_freq_all_cpus=162000

scaling_max_gps_freq=1242000

scaling_max_suspend_freq=1134000

scaling_max_oncall_freq=810000

scaling_min_suspend_freq=270000

cpu_voltage_switch=off

CPUVOLT1=1150000

CPUVOLT2=1112500

CPUVOLT3=1075000

CPUVOLT4=1037500

CPUVOLT5=1000000

CPUVOLT6=975000

CPUVOLT7=962500

CPUVOLT8=950000

CPUVOLT9=925000

CPUVOLT10=900000

CPUVOLT11=887500

CPUVOLT12=875000

CPUVOLT13=875000

CPUVOLT14=875000

CPUVOLT15=875000

CPUVOLT16=825000

CPUVOLT17=825000

scaling_governor_all_cpus=alucard

up_threshold=70

up_threshold_at_min_freq=60

sampling_rate=60000

sampling_down_factor=1

freq_step=20

down_differential=5

freq_for_responsiveness=486000

down_threshold=30

inc_cpu_load_at_min_freq=60

inc_cpu_load=80

dec_cpu_load_at_min_freq=40

dec_cpu_load=60

freq_for_responsiveness_max=1890000

freq_responsiveness=918000

pump_inc_step=2

pump_dec_step=1

freq_step_at_min_freq=20

freq_up_brake_at_min_freq=30

freq_up_brake=30

freq_step_dec=10

freq_step_dec_at_max_freq=10

scaling_governor_all_cpus_sleep=alucard

sampling_rate_sleep=60000

cpuhotplugging=3

eco_mode_active=0

strict_mode_active=0

hotplug_sampling_rate=60

cpu_up_rate=2

cpu_down_rate=5

hotplug_freq_1_1=1242000

hotplug_freq_2_0=810000

hotplug_freq_2_1=1566000

hotplug_freq_3_0=918000

hotplug_freq_3_1=1674000

hotplug_freq_4_0=1026000

hotplug_load_1_1=65

hotplug_load_2_0=30

hotplug_load_2_1=72

hotplug_load_3_0=36

hotplug_load_3_1=78

hotplug_load_4_0=42

hotplug_rq_1_1=100

hotplug_rq_2_0=100

hotplug_rq_2_1=200

hotplug_rq_3_0=200

hotplug_rq_3_1=300

hotplug_rq_4_0=300

maxcoreslimit=4

maxcoreslimit_sleep=1

eco_mode_active_sleep=1

strict_mode_active_sleep=0

msm_thermal=intelli_temp

enabled=off

core_limit_temp_degC=80

limit_temp_degC=70

governor=ondemand

max_pwrlevel=1

min_pwrlevel=3

thermal_pwrlevel=1

dvfs_boost_mode=2

dvfs_min_touch_limit=1134000

dvfs_min_touch_limit_second=810000

syn_touch_booster_off_time=300

syn_touch_booster_chg_time=200

gpio_key_booster_off_time=300

gpio_key_booster_chg_time=200

cortexbrain_read_ahead_kb=128

internal_iosched=zen

sd_iosched=zen

internal_iosched_sleep=noop

sd_iosched_sleep=noop

auto_oom=on

oom_config_screen_on=default

oom_config_screen_off=medium

dirty_background_ratio=20

dirty_ratio=40

swappiness=0

gpsregion=Europe

init_d=off

logger=off

pwm_value=75

force_fast_charge=0

usb_mode=default

auto_mount_sd=on

Dyn_fsync_active=1

cortexbrain_background_process=1

android_logger=auto

cortexbrain_auto_tweak_mobile=off

cortexbrain_auto_tweak_mobile_sleep_delay=30

cortexbrain_auto_tweak_wifi=off

cortexbrain_auto_tweak_wifi_sleep_delay=30

cortexbrain_firewall=on

cortexbrain_tcp=on

cortexbrain_tcp_ram=off

cortexbrain_ipv6=off

cortexbrain_memory=on

cortexbrain_system=on

cortexbrain_kernel_tweaks=on

cortexbrain_cpu=on

cortexbrain_io=on

cifs_module=off

I use socims alucard kernel build.