code: public void requestBatteryLevel(int nodeId, int endpoint) {
  		ZWaveNode node = this.getNode(nodeId);
  		SerialMessage serialMessage = null;
  		
  		ZWaveBatteryCommandClass zwaveBatteryCommandClass = (ZWaveBatteryCommandClass)node.resolveCommandClass(ZWaveCommandClass.CommandClass.BATTERY, endpoint);
  		
  		if (zwaveBatteryCommandClass == null) {
  			logger.error("No Command Class BATTERY found on node {}, instance/endpoint {} to request value.", nodeId, endpoint);
  			return;
  		}
  			 
  		serialMessage = node.encapsulate(zwaveBatteryCommandClass.getValueMessage(), zwaveBatteryCommandClass, endpoint);
  		
  		if (serialMessage != null)
  			this.sendData(serialMessage);
  	}
docs: Request the battery level from the node / endpoint;
  @param nodeId the node id to request the battery level for.
  @param endpoint the endpoint to request the battery level for.