I just received the EG4 18 amp 48 volt charger. Is it safe to charge the two EG4 Lifepower batteries from an exterior source (the new 48 volt charger) while the inverter (EG4 3000) is operating or should I disconnect the batteries from the inverter to charge them? I'll only use the new battery charger plugged into a Bluetti and in rare circumstances when solar isn't enough and grid is down, but just want to see if anyone has experience with this.