Car was damaged in a front end wreck. Took me years to repair it myself. HV and AUX batteries dead. Replaced AUX battery. Won't start, but may have other issues (will deployed airbags and seatbelt retractors prevent READY LIGHT?). All dash lights will light up, but only the ABS and Airbag lights stay lit. Assuming the other issues are not preventing the READY LIGHT, do I need to charge the HV battery? What's the best way (I prefer to avoid the dealer if I can)?