I installed a Bosch EL-51254 Charging Station 16 months ago shortly after I got my Spark. A couple of weeks ago I started having problems getting the car to charge. At first I could get it to work if I wiggled the plug a little or disconnected and reconnected. Indicator light on the Bosch came on and car charged fine on 110 v or public level 2 chargers. I called Bosch to find out where I could send it for repair (warrantee is 12 months), they told me they do not repair them. I came to the conclusion that the J1772 plug was the problem and replaced the plug and cord with a Leviton unit, works fine now. Leviton's plug is much heaver than the Bosch one and they claim it is good for 10K connections. This is not a difficult job, took about 1 1/2 hours.