charging lead battery question

[oldtimer]

AC outlet with 120V
Car adapter with 12V

For a full charge, it needs 10 hours on AC. However, using a car adapter, it recommends that you charge it for a maximum of 7 hours. Why? (This is assuming that you'll have the car running so you won't drain batteries.)

 

[Reptilezs]

the car adaptor charges at a higher rate than the ac adaptor

 

[jayflash]

The AC charger is limited by its small transformer - it's small to save manufacturing cost. The car charger has no transformer to limit the charging current.

 

[AlexGT]

Next question, Which of the two methods (AC Vs. DC) will give a better charge of the battery? I mean, get the full rated AH capacity out of it?

 

[Draco_Americanus]

both are probly just as good. But IMHO a slower charge rate is less stressfull to the batteries so the AC charger would be the charger I would use most times unless I needed a quicker charge