diff --git a/Aircraft/Instruments/hdg-c172s.xml b/Aircraft/Instruments/hdg-c172s.xml
index 25d5ba131..294fd7f24 100644
--- a/Aircraft/Instruments/hdg-c172s.xml
+++ b/Aircraft/Instruments/hdg-c172s.xml
@@ -83,6 +83,12 @@ Jan 30 2003
 
   <layer>
    <name>HDG Knob</name>
+   <condition>
+    <equals>
+     <property>/sim/instrument-options/omit-knobs</property>
+     <value></value>
+    </equals>
+   </condition>
    <w>88</w>
    <h>88</h>
    <texture>
diff --git a/Aircraft/c172p/Instruments/BatteryGauge/BatteryGauge.xml b/Aircraft/c172p/Instruments/BatteryGauge/BatteryGauge.xml
index 2e71fdf14..ba88c442b 100644
--- a/Aircraft/c172p/Instruments/BatteryGauge/BatteryGauge.xml
+++ b/Aircraft/c172p/Instruments/BatteryGauge/BatteryGauge.xml
@@ -23,9 +23,9 @@
   <object-name>PtrTipL</object-name>
   <property>systems/electrical/amps</property>
   <interpolation>
-   <entry><ind>-40</ind><dep>-45</dep></entry>
+   <entry><ind>-40</ind><dep>-30</dep></entry>
    <entry><ind>0</ind><dep>0</dep></entry>
-   <entry><ind>40</ind><dep>45</dep></entry>
+   <entry><ind>40</ind><dep>33</dep></entry>
   </interpolation>
   <axis> 
    <x>1</x>