If you have checked the battery and made sure that the new alternator is working, the only other possibility is that something is staying on when the ignition is off. Not all new alternators are perfect, sometimes they come with a faulty component that can drain the battery. Also, older batteries can slowly drain if the plates are starting to fail. It's difficult to just give one solution to a problem with so many possibilities.
The computer only resets when the battery is removed. The alternator just charges the battery, so if the battery is left connected when the alternator is replaced, the computer should not reset.
did you check the alternator??
Inside the alternator
Voltage regulator or loose wire.
Check the battery cables or starter.
Alternator is not charging. Have it tested and/or replaced.
You can have the alternator tested free of charge at just about any major auto parts store. By the way, a bad alternator will not "discharge" a battery - the alternator's function is to provide the charge to the battery. If the alternator is faulty, then it is not providing the charge necessary to keep other components from discharging the battery. I had the alternator tested and it was charging. If the alternator has a bad diode, it will discharge the battery. I replaced the alternator and everything is fine.
It could be an alternator. Check with a mechanic if that is the issue.
Voltage Regulator?
alternator needs to be replaced. battery also might be a problem due to the alternator not charging it
defective alternator
The battery light coming on in your Town and Country minivan means that the alternator needs to be replaced. The alternator charges the battery and if it goes bad it will not charge the battery.