diff --git a/configuration-example.yaml b/configuration-example.yaml
index 7d42c5e2565a29115becfed5086b67c7618c7211..0ab3e8caf62a9ff346215ee343952f55e14a9c3f 100644
--- a/configuration-example.yaml
+++ b/configuration-example.yaml
@@ -15,7 +15,8 @@ sync:
   inter_batch_delay: 5
 
   # Batch size for Google API calls. Google supports batching requests together
-  # into one API call. Default: 50.
+  # into one API call. This can be no greater than 1000 but in practice this
+  # should be less to avoid hitting other Google rate limits. Default: 50.
   batch_size: 50
 
 # Configure limits defining maximum scope of changes.