diff --git a/src/pyutil/jsonutil.py b/src/pyutil/jsonutil.py
index cf5caaa6578705bd1485133fa90411f331d7af01..f058c5535162548fbc0d022a741618e82dacf90b 100644
--- a/src/pyutil/jsonutil.py
+++ b/src/pyutil/jsonutil.py
@@ -805,7 +805,7 @@ def json_basic_do(ns, taskuuid, lat, lon, alt, request, node_uuid="", use_alias=
     return jobj;
 
 def json_basic_exchange_battery(ns, depot, battery_location, battery_uuid, node_uuid="", use_alias=False,
-                                use_depot=True, lat=0.0, lon=0.0, alt=0.0):
+                                use_depot=True, lat=0.0, lon=0.0, alt=0.0, exchange_unit="/dji0"):
     jobj = {
         "children": [],
         "common_params": get_common_params (ns, use_alias, node_uuid),                
@@ -814,6 +814,7 @@ def json_basic_exchange_battery(ns, depot, battery_location, battery_uuid, node_
             "depot": depot,            
             "battery-location": battery_location,
             "battery-uuid": battery_uuid,
+            "exchange-unit": exchange_unit,
             "use-depot-flag": use_depot,
             "exchange-position": {
                 "altitude": alt,