This review is for the ac outlet charger only..I haven't used the car adapterThis is a great deal..Ive read one person saying it killed their "ipod" i dont know if he meant sansa or not..Ive used it with My e250 and my fuze..I use it as the sole charger..I Haven't used the usb charger in months..It works great..and..I can listen while I charge..No problems..chagres great..and Ive left it charging for 3 days at least on several occasions. So, I know it doesnt over charge.Same battery life as always on my sansasI own two of these. Both work great..I'm sure there are some defective ones..especially at this price.But the two I purchased work perfect.