slow charge with original car charger??

It could be one of the many reasons. If the battery is starting to fail, no matter if you use gold-plated-with-encrusted-diamonds-and-blessed-by-the-pope-with-Steve-Jobs-holy-sweat cables and connectors, it just won't charge properly.
 
LOL

yea i know. well the store people were extra nice and sent me 2 new cables that work properly.
so until now it charges ok. no glitches.