Revo Low Batt tiers

  bool low_batt_a_ = false;                      // BC REVO BATT LEVELS
  bool low_batt_b_ = false;                      // BC REVO BATT LEVELS
  bool low_batt_c_ = false;                      // BC REVO BATT LEVELS
  bool low_batt_d_ = false;                      // BC REVO BATT LEVELS



  void Loop() override {
    CallMotion();

    if (on_pending_ && millis() - on_pending_base_ >= on_pending_delay_) {
      on_pending_ = false;
      SaberBase::TurnOn();
    }
    if (clash_pending1_) {
      clash_pending1_ = false;
      Clash(pending_clash_is_stab1_, pending_clash_strength1_);
    }
    if (clash_pending_ && millis() - last_clash_ >= clash_timeout_) {
      clash_pending_ = false;
      Clash2(pending_clash_is_stab_, pending_clash_strength_);
    }
    CheckLowBattery();
#ifdef LOW_BATT_TIERED_WARNINGS
    if (battery_monitor.battery() < 3.25 && (!low_batt_a_)){
      ::CommandParser::DoParse("play", "lowbatt1.wav");
      low_batt_a_ = true;
    }
    if (battery_monitor.battery() < 3.20 && (!low_batt_b_)){
      ::CommandParser::DoParse("play", "lowbatt2.wav");
      low_batt_b_ = true;
    }
    if (battery_monitor.battery() < 3.15 && (!low_batt_c_)){
      ::CommandParser::DoParse("play", "lowbatt3.wav");
      low_batt_c_ = true;
    }
    if (battery_monitor.battery() < 3.10 && (!low_batt_d_)){
      ::CommandParser::DoParse("play", "lowbatt4.wav");
      low_batt_d_ = true;
    }
#endif
#ifdef ENABLE_AUDIO
    if (track_player_ && !track_player_->isPlaying()) {
      track_player_.Free();
    }
#endif