I was not happy with their mobile battery service. After getting my car started with a jump-start they then needed to run some "diagnostic testing" to determine the quality of my battery. The battery test came out as "needs to be replaced". I was told by the service person my car would not start the next day unless I got a new battery. He just happened to have a brand new battery available for purchase right then and there from their service truck. At the time, it appeared the service person was doing me a favor by getting me a new battery to ensure my car would start again. It seems to me as if this service truck comes with the intent of selling a new AAA battery. I am disappointed in this AAA service. This is not what I expect when I buy my yearly membership. It states on their website that AAA is "Roadside Assistance You Can Trust". This mobile battery truck is not service I trust.
I have heard of other people being told that their battery would not hold a charge and must be replaced, only to find their car starting without a problem after recharging the battery. For instance, one person I know of needed a jump-start from AAA after the interior light was left on over-night. The service person indicated the battery needed to be replaced and offered to get them a brand new AAA battery. They declined, and were told again they really should have the battery replaced. They took the car to their local shop, which did a full recharge of the battery (took 1 hour). That was several weeks ago, and they have had no problems with the battery or starting the car since. Their battery is not brand new, but it is still working well enough to start their car.
Be aware of this, and that the service person may try to sell a battery. I would advise taking the car to your regular mechanic shop to have them evaluate it.
It may be that you do not need a new battery.