diff --git a/extra/usb_power/powerlog.py b/extra/usb_power/powerlog.py
index eaa2ffd18d..81d050bb91 100755
--- a/extra/usb_power/powerlog.py
+++ b/extra/usb_power/powerlog.py
@@ -648,7 +648,7 @@ class powerlog(object):
       self._data.CalculateStats()
       if self._print_stats:
         self._data.PrintSummary()
-      save_dir = datetime.datetime.now().strftime('sweetberry%Y%m%d%H%M%S')
+      save_dir = datetime.datetime.now().strftime('sweetberry%Y%m%d%H%M%S.%f')
       if self._stats_dir:
         stats_dir = os.path.join(self._stats_dir, save_dir)
         self._data.SaveSummary(stats_dir)