insufficient charging current

I already have two cheaper car chargers for my phone, a Nexus 4, this I use to navigate with Navigon and it needs to hang to the charger. In my two cheaper chargers mobile phones in addition to the navigation even slowly fully charged, here in this the mobile discharges slowly but steadily, so the charging current is too low and not to use the unit for long distances, otherwise I would be satisfied, just because the thin cable can be tailored in length, the search for the perfect charger thus proceeds.