Which do you use? I've been burning through them lately. I had a ventev from Verizon which charged so quickly I thought something was wrong. Stopped working well after 2 months. Just replaced it again.
Segawoot Apple MFi Certified Lightning Connector and Micro USB Nylon Braided Charging/SYNC Cable for iPhones iPads Samsung Galaxy S6, S5 and other micro USB enable devices,1.2 Meter, Black" on Amazon
Ive been having good luck with this one. It does both usb and iphone and is long enough to reach the back seat. The cable is braided and seems pretty tough.