time picker returning null value if start and end time both same

 <input type="text" id="from" class="form-control timepicker timepicker-no-seconds" name="start_activity">

<input type="text" id="to" class="form-control timepicker timepicker-no-seconds" name="end_activity">

In script for both is :
$('#from').timepicker();
 $('#to').timepicker();

i have two time picker in a form but when i am saving start time and end time as same then like start is 4pm and end also 4pm then it returning me the null value in end time when i am getting the value from the database.