diff --git a/Drone/copter_client.py b/Drone/copter_client.py
index ba8738c..f2ac110 100644
--- a/Drone/copter_client.py
+++ b/Drone/copter_client.py
@@ -672,7 +672,10 @@ def telemetry_loop():
                         batt_empty = batt_empty_param.value.real
                         batt_charged = batt_charged_param.value.real
                         batt_cells = batt_cells_param.value.integer
-                        telemetry = telemetry._replace(battery_p = '{}'.format(int(min((ros_telemetry.voltage/batt_cells - batt_empty)/(batt_charged - batt_empty)*100., 100))))
+                        try:
+                            telemetry = telemetry._replace(battery_p = '{}'.format(int(min((ros_telemetry.voltage/batt_cells - batt_empty)/(batt_charged - batt_empty)*100., 100))))
+                        except ValueError:
+                            telemetry = telemetry._replace(battery_p = 'nan')
                     else:
                         telemetry = telemetry._replace(battery_p = 'nan')
                     telemetry = telemetry._replace(calibration_status = get_calibration_status())