diff --git a/src/board/system76/darp5/battery.c b/src/board/system76/darp5/battery.c
index 9defbd5..28b813e 100644
--- a/src/board/system76/darp5/battery.c
+++ b/src/board/system76/darp5/battery.c
@@ -1,14 +1,7 @@
 #include <board/gpio.h>
+#include <board/smbus.h>
 #include <common/debug.h>
-#include <ec/i2c.h>
 
-int smbus_read(uint8_t address, uint8_t command, uint16_t * data) {
-    return i2c_get(&I2C_0, address, command, (uint8_t *)data, 2);
-}
-
-int smbus_write(uint8_t address, uint8_t command, uint16_t data) {
-    return i2c_set(&I2C_0, address, command, (uint8_t *)&data, 2);
-}
 
 // ChargeOption0 flags
 // Low Power Mode Enable
diff --git a/src/board/system76/darp5/board.mk b/src/board/system76/darp5/board.mk
index 7820e8d..89f530b 100644
--- a/src/board/system76/darp5/board.mk
+++ b/src/board/system76/darp5/board.mk
@@ -16,6 +16,9 @@ CFLAGS+=-DLEVEL=2
 # Enable I2C debug on 0x76
 CFLAGS+=-DI2C_DEBUGGER=0x76
 
+# Set battery I2C bus
+CFLAGS+=-DI2C_SMBUS=I2C_0
+
 # Add scratch ROM source
 SCRATCH_DIR=$(BOARD_DIR)/scratch
 SCRATCH_SRC=$(wildcard $(SCRATCH_DIR)/*.c)
diff --git a/src/board/system76/darp5/include/board/smbus.h b/src/board/system76/darp5/include/board/smbus.h
index 437844a..6b3b141 100644
--- a/src/board/system76/darp5/include/board/smbus.h
+++ b/src/board/system76/darp5/include/board/smbus.h
@@ -4,5 +4,7 @@
 #include <ec/smbus.h>
 
 void smbus_init(void);
+int smbus_read(uint8_t address, uint8_t command, uint16_t * data);
+int smbus_write(uint8_t address, uint8_t command, uint16_t data);
 
 #endif // _BOARD_SMBUS_H
diff --git a/src/board/system76/darp5/scratch/scratch.mk b/src/board/system76/darp5/scratch/scratch.mk
index 981642d..5fde8e4 100644
--- a/src/board/system76/darp5/scratch/scratch.mk
+++ b/src/board/system76/darp5/scratch/scratch.mk
@@ -9,7 +9,11 @@ SCRATCH_CFLAGS+=\
 	-Isrc/common/include \
 	-Isrc/ec/$(EC)/include
 
-#SCRATCH_CFLAGS+=-DI2C_DEBUGGER=0x76
+# Enable I2C debug on 0x76
+SCRATCH_CFLAGS+=-DI2C_DEBUGGER=0x76
+
+# Set battery I2C bus
+SCRATCH_CFLAGS+=-DI2C_SMBUS=I2C_0
 
 SCRATCH_BUILD=$(BUILD)/scratch
 SCRATCH_OBJ=$(patsubst src/%.c,$(SCRATCH_BUILD)/%.rel,$(SCRATCH_SRC))
diff --git a/src/board/system76/darp5/scratch/stdio.c b/src/board/system76/darp5/scratch/stdio.c
index 2a552ab..9bdb177 100644
--- a/src/board/system76/darp5/scratch/stdio.c
+++ b/src/board/system76/darp5/scratch/stdio.c
@@ -14,7 +14,7 @@ int putchar(int c) {
     SBUF = byte;
 #endif
 #ifdef I2C_DEBUGGER
-    i2c_send(&I2C_0, I2C_DEBUGGER, &byte, 1);
+    i2c_send(&I2C_SMBUS, I2C_DEBUGGER, &byte, 1);
 #endif
     return (int)byte;
 }
diff --git a/src/board/system76/darp5/smbus.c b/src/board/system76/darp5/smbus.c
index c61c31d..a5dfaec 100644
--- a/src/board/system76/darp5/smbus.c
+++ b/src/board/system76/darp5/smbus.c
@@ -17,5 +17,13 @@ void smbus_init(void) {
     SMB45P3USH = 0x01;
 
     // Set up for i2c usage
-    i2c_reset(&I2C_0, true);
+    i2c_reset(&I2C_SMBUS, true);
+}
+
+int smbus_read(uint8_t address, uint8_t command, uint16_t * data) {
+    return i2c_get(&I2C_SMBUS, address, command, (uint8_t *)data, 2);
+}
+
+int smbus_write(uint8_t address, uint8_t command, uint16_t data) {
+    return i2c_set(&I2C_SMBUS, address, command, (uint8_t *)&data, 2);
 }
diff --git a/src/board/system76/darp5/stdio.c b/src/board/system76/darp5/stdio.c
index 2a552ab..9bdb177 100644
--- a/src/board/system76/darp5/stdio.c
+++ b/src/board/system76/darp5/stdio.c
@@ -14,7 +14,7 @@ int putchar(int c) {
     SBUF = byte;
 #endif
 #ifdef I2C_DEBUGGER
-    i2c_send(&I2C_0, I2C_DEBUGGER, &byte, 1);
+    i2c_send(&I2C_SMBUS, I2C_DEBUGGER, &byte, 1);
 #endif
     return (int)byte;
 }
diff --git a/src/board/system76/galp3-c/battery.c b/src/board/system76/galp3-c/battery.c
index 488599c..f12af07 100644
--- a/src/board/system76/galp3-c/battery.c
+++ b/src/board/system76/galp3-c/battery.c
@@ -1,14 +1,7 @@
 #include <board/gpio.h>
+#include <board/smbus.h>
 #include <common/debug.h>
-#include <ec/i2c.h>
 
-int smbus_read(uint8_t address, uint8_t command, uint16_t * data) {
-    return i2c_get(&I2C_0, address, command, (uint8_t *)data, 2);
-}
-
-int smbus_write(uint8_t address, uint8_t command, uint16_t data) {
-    return i2c_set(&I2C_0, address, command, (uint8_t *)&data, 2);
-}
 
 // ChargeOption0 flags
 // Low Power Mode Enable
diff --git a/src/board/system76/galp3-c/board.mk b/src/board/system76/galp3-c/board.mk
index 7820e8d..89f530b 100644
--- a/src/board/system76/galp3-c/board.mk
+++ b/src/board/system76/galp3-c/board.mk
@@ -16,6 +16,9 @@ CFLAGS+=-DLEVEL=2
 # Enable I2C debug on 0x76
 CFLAGS+=-DI2C_DEBUGGER=0x76
 
+# Set battery I2C bus
+CFLAGS+=-DI2C_SMBUS=I2C_0
+
 # Add scratch ROM source
 SCRATCH_DIR=$(BOARD_DIR)/scratch
 SCRATCH_SRC=$(wildcard $(SCRATCH_DIR)/*.c)
diff --git a/src/board/system76/galp3-c/include/board/smbus.h b/src/board/system76/galp3-c/include/board/smbus.h
index 437844a..6b3b141 100644
--- a/src/board/system76/galp3-c/include/board/smbus.h
+++ b/src/board/system76/galp3-c/include/board/smbus.h
@@ -4,5 +4,7 @@
 #include <ec/smbus.h>
 
 void smbus_init(void);
+int smbus_read(uint8_t address, uint8_t command, uint16_t * data);
+int smbus_write(uint8_t address, uint8_t command, uint16_t data);
 
 #endif // _BOARD_SMBUS_H
diff --git a/src/board/system76/galp3-c/scratch/scratch.mk b/src/board/system76/galp3-c/scratch/scratch.mk
index 981642d..5fde8e4 100644
--- a/src/board/system76/galp3-c/scratch/scratch.mk
+++ b/src/board/system76/galp3-c/scratch/scratch.mk
@@ -9,7 +9,11 @@ SCRATCH_CFLAGS+=\
 	-Isrc/common/include \
 	-Isrc/ec/$(EC)/include
 
-#SCRATCH_CFLAGS+=-DI2C_DEBUGGER=0x76
+# Enable I2C debug on 0x76
+SCRATCH_CFLAGS+=-DI2C_DEBUGGER=0x76
+
+# Set battery I2C bus
+SCRATCH_CFLAGS+=-DI2C_SMBUS=I2C_0
 
 SCRATCH_BUILD=$(BUILD)/scratch
 SCRATCH_OBJ=$(patsubst src/%.c,$(SCRATCH_BUILD)/%.rel,$(SCRATCH_SRC))
diff --git a/src/board/system76/galp3-c/scratch/stdio.c b/src/board/system76/galp3-c/scratch/stdio.c
index 2a552ab..9bdb177 100644
--- a/src/board/system76/galp3-c/scratch/stdio.c
+++ b/src/board/system76/galp3-c/scratch/stdio.c
@@ -14,7 +14,7 @@ int putchar(int c) {
     SBUF = byte;
 #endif
 #ifdef I2C_DEBUGGER
-    i2c_send(&I2C_0, I2C_DEBUGGER, &byte, 1);
+    i2c_send(&I2C_SMBUS, I2C_DEBUGGER, &byte, 1);
 #endif
     return (int)byte;
 }
diff --git a/src/board/system76/galp3-c/smbus.c b/src/board/system76/galp3-c/smbus.c
index c61c31d..a5dfaec 100644
--- a/src/board/system76/galp3-c/smbus.c
+++ b/src/board/system76/galp3-c/smbus.c
@@ -17,5 +17,13 @@ void smbus_init(void) {
     SMB45P3USH = 0x01;
 
     // Set up for i2c usage
-    i2c_reset(&I2C_0, true);
+    i2c_reset(&I2C_SMBUS, true);
+}
+
+int smbus_read(uint8_t address, uint8_t command, uint16_t * data) {
+    return i2c_get(&I2C_SMBUS, address, command, (uint8_t *)data, 2);
+}
+
+int smbus_write(uint8_t address, uint8_t command, uint16_t data) {
+    return i2c_set(&I2C_SMBUS, address, command, (uint8_t *)&data, 2);
 }
diff --git a/src/board/system76/galp3-c/stdio.c b/src/board/system76/galp3-c/stdio.c
index 2a552ab..9bdb177 100644
--- a/src/board/system76/galp3-c/stdio.c
+++ b/src/board/system76/galp3-c/stdio.c
@@ -14,7 +14,7 @@ int putchar(int c) {
     SBUF = byte;
 #endif
 #ifdef I2C_DEBUGGER
-    i2c_send(&I2C_0, I2C_DEBUGGER, &byte, 1);
+    i2c_send(&I2C_SMBUS, I2C_DEBUGGER, &byte, 1);
 #endif
     return (int)byte;
 }
diff --git a/src/board/system76/lemp9/battery.c b/src/board/system76/lemp9/battery.c
index 223c428..af89f9d 100644
--- a/src/board/system76/lemp9/battery.c
+++ b/src/board/system76/lemp9/battery.c
@@ -1,13 +1,6 @@
+#include <board/smbus.h>
 #include <common/debug.h>
-#include <ec/i2c.h>
 
-int smbus_read(uint8_t address, uint8_t command, uint16_t * data) {
-    return i2c_get(&I2C_4, address, command, (uint8_t *)data, 2);
-}
-
-int smbus_write(uint8_t address, uint8_t command, uint16_t data) {
-    return i2c_set(&I2C_4, address, command, (uint8_t *)&data, 2);
-}
 
 // ChargeOption0 flags
 // Low Power Mode Enable
diff --git a/src/board/system76/lemp9/board.mk b/src/board/system76/lemp9/board.mk
index bb19bee..7773bec 100644
--- a/src/board/system76/lemp9/board.mk
+++ b/src/board/system76/lemp9/board.mk
@@ -16,6 +16,9 @@ CFLAGS+=-DLEVEL=2
 # Enable I2C debug on 0x76
 CFLAGS+=-DI2C_DEBUGGER=0x76
 
+# Set battery I2C bus
+CFLAGS+=-DI2C_SMBUS=I2C_4
+
 # Add scratch ROM source
 SCRATCH_DIR=$(BOARD_DIR)/scratch
 SCRATCH_SRC=$(wildcard $(SCRATCH_DIR)/*.c)
diff --git a/src/board/system76/lemp9/include/board/smbus.h b/src/board/system76/lemp9/include/board/smbus.h
index 437844a..6b3b141 100644
--- a/src/board/system76/lemp9/include/board/smbus.h
+++ b/src/board/system76/lemp9/include/board/smbus.h
@@ -4,5 +4,7 @@
 #include <ec/smbus.h>
 
 void smbus_init(void);
+int smbus_read(uint8_t address, uint8_t command, uint16_t * data);
+int smbus_write(uint8_t address, uint8_t command, uint16_t data);
 
 #endif // _BOARD_SMBUS_H
diff --git a/src/board/system76/lemp9/scratch/scratch.mk b/src/board/system76/lemp9/scratch/scratch.mk
index 981642d..e0949f3 100644
--- a/src/board/system76/lemp9/scratch/scratch.mk
+++ b/src/board/system76/lemp9/scratch/scratch.mk
@@ -9,7 +9,11 @@ SCRATCH_CFLAGS+=\
 	-Isrc/common/include \
 	-Isrc/ec/$(EC)/include
 
-#SCRATCH_CFLAGS+=-DI2C_DEBUGGER=0x76
+# Enable I2C debug on 0x76
+SCRATCH_CFLAGS+=-DI2C_DEBUGGER=0x76
+
+# Set battery I2C bus
+SCRATCH_CFLAGS+=-DI2C_SMBUS=I2C_4
 
 SCRATCH_BUILD=$(BUILD)/scratch
 SCRATCH_OBJ=$(patsubst src/%.c,$(SCRATCH_BUILD)/%.rel,$(SCRATCH_SRC))
diff --git a/src/board/system76/lemp9/scratch/stdio.c b/src/board/system76/lemp9/scratch/stdio.c
index bd5e99e..9bdb177 100644
--- a/src/board/system76/lemp9/scratch/stdio.c
+++ b/src/board/system76/lemp9/scratch/stdio.c
@@ -14,7 +14,7 @@ int putchar(int c) {
     SBUF = byte;
 #endif
 #ifdef I2C_DEBUGGER
-    i2c_send(&I2C_4, I2C_DEBUGGER, &byte, 1);
+    i2c_send(&I2C_SMBUS, I2C_DEBUGGER, &byte, 1);
 #endif
     return (int)byte;
 }
diff --git a/src/board/system76/lemp9/smbus.c b/src/board/system76/lemp9/smbus.c
index 7808cbe..a5dfaec 100644
--- a/src/board/system76/lemp9/smbus.c
+++ b/src/board/system76/lemp9/smbus.c
@@ -17,5 +17,13 @@ void smbus_init(void) {
     SMB45P3USH = 0x01;
 
     // Set up for i2c usage
-    i2c_reset(&I2C_4, true);
+    i2c_reset(&I2C_SMBUS, true);
+}
+
+int smbus_read(uint8_t address, uint8_t command, uint16_t * data) {
+    return i2c_get(&I2C_SMBUS, address, command, (uint8_t *)data, 2);
+}
+
+int smbus_write(uint8_t address, uint8_t command, uint16_t data) {
+    return i2c_set(&I2C_SMBUS, address, command, (uint8_t *)&data, 2);
 }
diff --git a/src/board/system76/lemp9/stdio.c b/src/board/system76/lemp9/stdio.c
index bd5e99e..9bdb177 100644
--- a/src/board/system76/lemp9/stdio.c
+++ b/src/board/system76/lemp9/stdio.c
@@ -14,7 +14,7 @@ int putchar(int c) {
     SBUF = byte;
 #endif
 #ifdef I2C_DEBUGGER
-    i2c_send(&I2C_4, I2C_DEBUGGER, &byte, 1);
+    i2c_send(&I2C_SMBUS, I2C_DEBUGGER, &byte, 1);
 #endif
     return (int)byte;
 }