diff --git a/src/mqtt.cpp b/src/mqtt.cpp
index 7be71f867..eb0601eb0 100644
--- a/src/mqtt.cpp
+++ b/src/mqtt.cpp
@@ -687,8 +687,7 @@ void Mqtt::register_mqtt_ha_binary_sensor(const __FlashStringHelper * name, cons
         return;
     }
 
-    DynamicJsonDocument doc(EMSESP_MAX_JSON_SIZE_SMALL);
-    // StaticJsonDocument<EMSESP_MAX_JSON_SIZE_SMALL> doc;
+    StaticJsonDocument<EMSESP_MAX_JSON_SIZE_SMALL> doc;
 
     doc["name"]    = name;
     doc["uniq_id"] = entity;
@@ -716,31 +715,16 @@ void Mqtt::register_mqtt_ha_binary_sensor(const __FlashStringHelper * name, cons
     snprintf_P(ha_device, sizeof(ha_device), PSTR("ems-esp-%s"), EMSdevice::device_type_2_device_name(device_type).c_str());
     ids.add(ha_device);
 
-    doc.shrinkToFit();
-
     char topic[MQTT_TOPIC_MAX_SIZE];
     snprintf_P(topic, sizeof(topic), PSTR("homeassistant/binary_sensor/ems-esp/%s/config"), entity);
 
-    // convert json to string and publish immediately with retain forced to true
-    char payload_text[256];
-    serializeJson(doc, payload_text); // convert json to string
-    uint16_t packet_id = mqttClient_->publish(topic, 0, true, payload_text);
-#if defined(EMSESP_STANDALONE)
-    LOG_DEBUG(F("Publishing topic %s"), topic);
-#else
-    if (!packet_id) {
-        LOG_ERROR(F("Failed to publish topic %s"), topic);
-    } else {
-        LOG_DEBUG(F("Publishing topic %s"), topic);
-    }
-#endif
-
-    // delay(MQTT_PUBLISH_WAIT);
-    delay(50);
+    // queue MQTT publish
+    publish(topic, doc.as<JsonObject>());
 }
 
 // HA config for a normal 'sensor' type
 // entity must match the key/value pair in the _data topic
+// some string copying here into chars, it looks messy but does help with heap fragmentation issues
 void Mqtt::register_mqtt_ha_sensor(const char *                prefix,
                                    const __FlashStringHelper * suffix,
                                    const __FlashStringHelper * name,
@@ -797,8 +781,7 @@ void Mqtt::register_mqtt_ha_sensor(const char *                prefix,
     }
     new_name[0] = toupper(new_name[0]); // capitalize first letter
 
-    DynamicJsonDocument doc(EMSESP_MAX_JSON_SIZE_SMALL);
-    // StaticJsonDocument<EMSESP_MAX_JSON_SIZE_SMALL> doc;
+    StaticJsonDocument<EMSESP_MAX_JSON_SIZE_HA_CONFIG> doc;
 
     doc["name"]    = new_name;
     doc["uniq_id"] = uniq.c_str();
@@ -814,9 +797,8 @@ void Mqtt::register_mqtt_ha_sensor(const char *                prefix,
     JsonArray  ids = dev.createNestedArray("ids");
     ids.add(ha_device);
 
-    doc.shrinkToFit();
     // convert json to string and publish immediately with retain forced to true
-    char payload_text[256];
+    char payload_text[EMSESP_MAX_JSON_SIZE_HA_CONFIG];
     serializeJson(doc, payload_text); // convert json to string
 
     uint16_t packet_id = mqttClient_->publish(topic, 0, true, payload_text);
@@ -830,7 +812,6 @@ void Mqtt::register_mqtt_ha_sensor(const char *                prefix,
 #endif
     }
 
-    // delay(MQTT_PUBLISH_WAIT); // don't flood asynctcp
     delay(50); // enough time to send the short message out
 }
 } // namespace emsesp
diff --git a/src/mqtt.h b/src/mqtt.h
index cadcc9948..faf8c8f04 100644
--- a/src/mqtt.h
+++ b/src/mqtt.h
@@ -38,10 +38,11 @@
 
 using uuid::console::Shell;
 
-#define EMSESP_MAX_JSON_SIZE_SMALL 384  // for smaller json docs when using StaticJsonDocument
-#define EMSESP_MAX_JSON_SIZE_MEDIUM 768 // for medium json docs from ems devices, when using StaticJsonDocument
-#define EMSESP_MAX_JSON_SIZE_LARGE 1024 // for large json docs from ems devices, like boiler or thermostat data. Using StaticJsonDocument
-#define EMSESP_MAX_JSON_SIZE_DYN 2048   // for large json docs from web. Using DynamicJsonDocument
+#define EMSESP_MAX_JSON_SIZE_HA_CONFIG 256 // for small HA config payloads
+#define EMSESP_MAX_JSON_SIZE_SMALL 384     // for smaller json docs when using StaticJsonDocument
+#define EMSESP_MAX_JSON_SIZE_MEDIUM 768    // for medium json docs from ems devices, when using StaticJsonDocument
+#define EMSESP_MAX_JSON_SIZE_LARGE 1024    // for large json docs from ems devices, like boiler or thermostat data. Using StaticJsonDocument
+#define EMSESP_MAX_JSON_SIZE_DYN 2048      // for large json docs from web. Using DynamicJsonDocument
 
 namespace emsesp {