tanya tidak bisa append file log

[numus175]

gan mohon bantuan nya, ane buat log , tapi di txt file nya dia gk mau append/menambahkan yang data yang sudah ada ,
mohon bantuan nya, berikut code nya .

String strWrite = edtketerangan.getText().toString();
File myFile = new File("storage/sdcard1/documents/Log.txt");
BufferedWriter out = new BufferedWriter(new FileWriter(myFile));
FileOutputStream FOut = new FileOutputStream(myFile);
OutputStreamWriter myoutwriter = new OutputStreamWriter(FOut);
myoutwriter.append(strWrite);
myoutwriter.close();
FOut.close();