This SAE Aerospace Recommended Practice (ARP) describes three general types of Ground Support Equipment (GSE) battery chargers. The battery charger typically requiring up to 8 hours to recharge a 100% discharged battery, hereafter called âConventional Charger.â A charger, hereafter called âOpportunity Charger,â which has the ability to charge at a slightly faster rate than a conventional charger. A charger, hereafter called âFast Charger,â which has the ability to charge at a much faster rate than a conventional charger. Recommendations that apply to all types will refer generically to âcharger.â