diff --git a/Core/Inc/PWM_control.h b/Core/Inc/PWM_control.h
index 590b0ef..8e67096 100644
--- a/Core/Inc/PWM_control.h
+++ b/Core/Inc/PWM_control.h
@@ -5,6 +5,24 @@
 #include "ADBMS_LL_Driver.h"
 #include "main.h"
 
+/*  The PWM period (1/FPWM) is defined by the following parameters: 
+ARR value, the Prescaler value, and the internal clock itself which drives the timer module FCLK.
+F_PWM = (F_CLK)/((ARR + 1) * (PSC + 1))
+
+F_CLK = 16 MHz
+
+POWERGROUND ESC Signal: pulse every 20 ms, 1 ms = 0%, 2 ms = 100%
+FREQ = 50 Hz -> 16 MHz/50 Hz = 320000 = ((9999 + 1) * (31 + 1))
+DUTY CYCLE = 1/20 -> 0%, DUTY CYCLE = 2/20 -> 100% 
+CCR * DUTY_CYCLE
+CCR: 1/20 -> 500, 2/20 -> 1000
+*/
+#define POWERGROUND_FREQ            50
+#define POWERGROUND_MAX_DUTY_CYCLE  0.05
+#define POWERGROUND_MIN_DUTY_CYCLE  0.1
+
+//#define BATTERY_COOLING_FREQ        20000
+
 void PWM_control_init(TIM_HandleTypeDef powerground1, TIM_HandleTypeDef powerground2, TIM_HandleTypeDef battery_cooling);
 
 void PWM_powerground_control(uint8_t percent);
diff --git a/Core/Src/PWM_control.c b/Core/Src/PWM_control.c
index 74c8bc3..5df4da1 100644
--- a/Core/Src/PWM_control.c
+++ b/Core/Src/PWM_control.c
@@ -1,28 +1,41 @@
 #include "PWM_control.h"
-#include "stm32f3xx_hal_tim.h"
 #include <stdint.h>
 
 uint8_t powerground_status;
 uint8_t battery_cooling_status;
+uint8_t powerground_percent;
+uint8_t battery_cooling_percent;
+//uint32_t powerground1_CCR, powerground2_CCR, battery_cooling_CCR;
 
 TIM_HandleTypeDef powerground1, powerground2, battery_cooling;
 
+/*
+  Pulse width modulation mode allows for generating a signal with a frequency determined by 
+  the value of the TIMx_ARR register and a duty cycle determined by the value of the TIMx_CCRx register. 
+*/
+
 void PWM_control_init(TIM_HandleTypeDef powerground1, TIM_HandleTypeDef powerground2, TIM_HandleTypeDef battery_cooling){
   powerground_status = 0;
-  battery_cooling = 0;
+  battery_cooling_status = 0;
 
-  HAL_TIM_PWM_Start(&powerground1, 1);
-  HAL_TIM_PWM_Start(&powerground2, 4);
-  HAL_TIM_PWM_Start(&battery_cooling, 3);
+  HAL_TIM_PWM_Start(&powerground1, 1);        //TIM15CH1
+  HAL_TIM_PWM_Start(&powerground2, 2);        //TIM15CH2
+  HAL_TIM_PWM_Start(&battery_cooling, 3);     //TIM1CH3
 
-  //__HAL_TIM_SET_COMPARE(&powerground1, 1, 0);
-  //__HAL_TIM_SET_COMPARE(&powerground2, 4, 0);
-  //__HAL_TIM_SET_COMPARE(&battery_cooling, 3, 0);
+  powerground_percent = 0;
+  battery_cooling_percent = 0;
 }              
 
+/*
+  controls the duty cycle of the fans by setting the CCR of the channel percent/100 = x/ARR
+*/
 void PWM_powerground_control(uint8_t percent){
-  //uint8_t duty_cycle = (percent/100) * 65536;
-  //__HAL_TIM_SET_COMPARE(&powerground1, 1, 0);
+  if (percent > 100 || percent < 0)
+    return;
+
+  powerground_percent = percent/100;
+  TIM15->CCR1 = (POWERGROUND_MAX_DUTY_CYCLE-POWERGROUND_MIN_DUTY_CYCLE) * (percent/100) + POWERGROUND_MIN_DUTY_CYCLE;
+  TIM15->CCR2 = TIM15->CCR1; /* *1.01 or *0.99  if the speeds of the fans are different*/
 }
 
 void PWM_battery_cooling_control(uint8_t percent){
diff --git a/mvbms.ioc b/mvbms.ioc
index 5c75f5e..4c362af 100644
--- a/mvbms.ioc
+++ b/mvbms.ioc
@@ -23,10 +23,9 @@ Mcu.IP3=RCC
 Mcu.IP4=SPI1
 Mcu.IP5=SYS
 Mcu.IP6=TIM1
-Mcu.IP7=TIM2
-Mcu.IP8=TIM15
-Mcu.IP9=USART1
-Mcu.IPNb=10
+Mcu.IP7=TIM15
+Mcu.IP8=USART1
+Mcu.IPNb=9
 Mcu.Name=STM32F302C(B-C)Tx
 Mcu.Package=LQFP48
 Mcu.Pin0=PF0-OSC_IN
@@ -110,7 +109,7 @@ PA2.Signal=S_TIM15_CH1
 PA3.GPIOParameters=GPIO_Label
 PA3.GPIO_Label=PWM_PG_FAN2
 PA3.Locked=true
-PA3.Signal=S_TIM2_CH4
+PA3.Signal=S_TIM15_CH2
 PA4.GPIOParameters=GPIO_Label
 PA4.GPIO_Label=CSB
 PA4.Locked=true
@@ -190,7 +189,7 @@ ProjectManager.FreePins=true
 ProjectManager.HalAssertFull=false
 ProjectManager.HeapSize=0x200
 ProjectManager.KeepUserCode=true
-ProjectManager.LastFirmware=true
+ProjectManager.LastFirmware=false
 ProjectManager.LibraryCopy=1
 ProjectManager.MainLocation=Core/Src
 ProjectManager.NoMain=false
@@ -243,8 +242,8 @@ RCC.USBFreq_Value=16000000
 RCC.VCOOutput2Freq_Value=4000000
 SH.S_TIM15_CH1.0=TIM15_CH1,PWM Generation1 CH1
 SH.S_TIM15_CH1.ConfNb=1
-SH.S_TIM2_CH4.0=TIM2_CH4,PWM Generation4 CH4
-SH.S_TIM2_CH4.ConfNb=1
+SH.S_TIM15_CH2.0=TIM15_CH2,PWM Generation2 CH2
+SH.S_TIM15_CH2.ConfNb=1
 SPI1.BaudRatePrescaler=SPI_BAUDRATEPRESCALER_32
 SPI1.CalculateBaudRate=500.0 KBits/s
 SPI1.DataSize=SPI_DATASIZE_8BIT
@@ -255,9 +254,8 @@ SPI1.VirtualType=VM_MASTER
 TIM1.Channel-PWM\ Generation3\ CH3N=TIM_CHANNEL_3
 TIM1.IPParameters=Channel-PWM Generation3 CH3N
 TIM15.Channel-PWM\ Generation1\ CH1=TIM_CHANNEL_1
-TIM15.IPParameters=Channel-PWM Generation1 CH1
-TIM2.Channel-PWM\ Generation4\ CH4=TIM_CHANNEL_4
-TIM2.IPParameters=Channel-PWM Generation4 CH4
+TIM15.Channel-PWM\ Generation2\ CH2=TIM_CHANNEL_2
+TIM15.IPParameters=Channel-PWM Generation1 CH1,Channel-PWM Generation2 CH2
 USART1.IPParameters=VirtualMode-Asynchronous
 USART1.VirtualMode-Asynchronous=VM_ASYNC
 VP_SYS_VS_Systick.Mode=SysTick