It is normal. Current draw from this very tiny low intensity LED is not significant. This is what Fred, KE7X posted in the Yahoo KX3 group concerning the meaning of the flashes:
Here is what the KXBC3 LED blink patterns mean:
Low intensity single blink every 0.5 seconds.
The KX3 is shut off and the KXBC3 is in ultra low power “time keeping with
alarm” mode. The KXBC3 is normally powered from internal batteries or an external power source (whichever has the higher voltage) but will
continue to operate in this mode for at least 5 minutes (typically 20
minutes) if the batteries are removed.
Bright single blink every 2.5 seconds.
The KX3 power is on and the KXBC3 is operating normally but is not charging the batteries.
Bright single blink every 0.75 seconds.
A charge cycle is in progress.
Bright triple blink every 2.5 seconds
A charge cycle is in progress but is currently suspended due to temperature or insufficient external supply voltage.
Morse ‘U” every 2.5 seconds.
A future firmware upgrade may allow a charge cycle to be in progress but
with a low external supply voltage. The actual charge current will be
less than the normal level.
Cheers and 73 all,Fred KE7X
From: Robin <[hidden email]>
To: [hidden email] Sent: Sunday, June 2, 2013 8:36 AM
Subject: [Elecraft] Red LED in KX3...
I can see a Red LED lit and blinking intermittantly inside the KX3 casing
(looking through the keyer hole). It is also lit when the radio is turned
off ... ? Is this normal.