diff --git a/components/panasonic_heatpump/README.md b/components/panasonic_heatpump/README.md
index eb19d57..7e6034e 100644
--- a/components/panasonic_heatpump/README.md
+++ b/components/panasonic_heatpump/README.md
@@ -12,6 +12,9 @@
 
 ![wiring.jpeg](../../prototypes/panasonic_heatpump/wiring.jpeg)
 
+You may also connect the +5V pin of the heatpump to the +5V pin of the ESP board.  
+But for me the current provided by the heatpump was quite unstable so I powered my ESP board through an USB cable.  
+
 ### CN-CNT Pinout (from top to bottom)
 
 pin | function