Please describe the three beeps. They can also be due to a charge timer being active, and trying to charge during the period it is set to not charge. Testing it is easy: let the car sit undisturbed for 15+ minutes then use a multimeter, set to DC Volts, to check the voltage between the Positive and Negative terminals. If it is below 12.2 volts then it may well be the problem.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.