I am here regarding the solution for how to charge my two AA batteries with car battery. If I connect my AA battery charger (with car adapter) holding two drained AA 2600maH batteries to a fully charged 12 volt 2AH SLA (sealed lead acid) battery, will it complete charge them? Do I need bigger sealed lead acid battery, perhaps 7AH? Is there any formula to get proper size? How can I charge my two AA batteries? I would really appreciate your useful information regarding this. Thanks.