How to lower power consumption ARDUINO and RFID mfrc522 - arduino

Question

Im making a project that i scan rfid cards to gain access to a door. I have made the code the way i want it to function but currently its drawing 22mA. I want this project to be powered by an 4Ah Lead acid battery.
I have removed the leds from the reader and from the arduino to lower consumption. Also i run arduino at 1Mhz and that looks that lowered the consumption a lot. Also i disabled Analog converter of arduino.
IM using arduino nano and RFID-RC522 reader
the output is an 5 volt relay.
Here is the code:
#include <SPI.h>
#include <MFRC522.h>
#include <EEPROM.h>
#define SS_PIN 10
#define RST_PIN 9
MFRC522 mfrc522(SS_PIN, RST_PIN);
#define relay 4
#define led 2
#define button 5
byte readCard[4];
byte storeCard[4];
byte lastCard[4] = {1,2,3,4};
uint8_t successread = 0;
int flag=0;
void setup() {
CLKPR = 0x80;
CLKPR = 0x04;
ADCSRA = 0;
pinMode(relay, OUTPUT);
pinMode(button, INPUT_PULLUP);
pinMode(led, OUTPUT);
digitalWrite(relay, LOW);
digitalWrite(led, LOW);
SPI.begin();
mfrc522.PCD_Init();
}
void loop() {
do {
successread = getID();
}
while(!successread);
digitalWrite(led, HIGH);
delayMicroseconds(100);
digitalWrite(led, LOW);
lastcard();
if(digitalRead(button)==LOW){
save_delCard();
}
if(checkID(readCard) && !(digitalRead(button)==LOW)){
if(flag==0){
digitalWrite(relay, HIGH);
flag = !flag;
}
else{
digitalWrite(relay, LOW);
flag = !flag;
}
}
}
/////////READ CARD FROM READER/////////////////
uint8_t getID(){
if ( ! mfrc522.PICC_IsNewCardPresent()) { //If a new PICC placed to RFID
reader continue
return 0;
}
if ( ! mfrc522.PICC_ReadCardSerial()) { //Since a PICC placed get
Serial and continue
return 0;
}
for (uint8_t i=0; i<4; i++){
readCard[i] = mfrc522.uid.uidByte[i];
}
mfrc522.PICC_HaltA(); // stop reading
return 1;
}
///////////////////SAVE OR DELETE CARD/////////////////////////
uint8_t save_delCard(){
uint8_t count = EEPROM.read(0);
int start = (count*4) + 1;
int num = count*4 +1;
if(checkID(readCard)){
uint8_t slot = slotcheck(readCard);
for(uint8_t m=0;m<4;m++){
EEPROM.write((num-m-1),0);
}
for(uint8_t k=0;k<4;k++){
EEPROM.write((((slot-1)*4)+1+k),lastCard[k]);
}
count--;
}
else{
count++;
}
for(uint8_t j=0; j<4;j++){
EEPROM.write(j + start, readCard[j]);
}
EEPROM.write(0,count);
return 0;
}
////////////////////READ FROM MEMORY//////////////////////////////////
uint8_t readID(uint8_t number){
uint8_t start = (number*4) + 1;
for(uint8_t j=0;j<4;j++){
storeCard[j] = EEPROM.read(start + j);
}
}
///////////////////COMPARE IDS///////////////////////////////
bool compare(byte arraya[],byte arrayb[]){
for(uint8_t i=0;i<4;i++){
if(arraya[i]!=arrayb[i]){
return false;
}
else{
return true;
}
}
}
/////////CHECK IF CARD IS IN MEMORY/////////////////////////////////////
bool checkID(byte arraya[]){
uint8_t count = EEPROM.read(0);
for(int i=0;i<count;i++){
readID(i);
if(compare(arraya, storeCard)){
return true;
}
else {
}
}
return false;
}
////////////////FINDS WHERE CARD IS IN MEMORY//////////////////
uint8_t slotcheck(byte arraya[]){
uint8_t count = EEPROM.read(0);
uint8_t slot=0;
for(int i=0;i<count;i++){
readID(i);
slot = i+1;
if(compare(arraya, storeCard)){
return slot;
}
else {
}
}
return NULL;
}
///////////////SAVES LAST CARD/////////////////////
void lastcard(){
uint8_t count = EEPROM.read(0);
for(uint8_t p=0;p<4;p++){
lastCard[p] = EEPROM.read((count*4)-3+p);
}
}
//////////////////////////////////////////////////////////////////