I am trying to hook up a charger to my 2013 Ducati Hypermotard. It's a bit of a long story so i'll try to keep it short as possible.
I had a Belkin dual USB charger that plugs into a cigarette lighter. I soldered to positive and negative and put a 5 amp fuse straight to the battery. I tested with my S3 - perfect. I hook up my S4 - perfect. The next day I hook up my S4 and I get an error message. "The connected charger is incompatible with this phone. To prevent damage to your phone, charging has been stopped. To continue charging, use the original charger and cable that were provided with the phone." It stops charging on any charger. Verizon sends a new S4 out for warranty, but my phone starts working again so I sent back the replacement phone (nervous about getting charged for a ding on the corner).
I was nervous with that usb outlet, so I bought Trackside USB outlet. I hook this up, my S3 charges perfect, but the S4 doesnt even recognize it. I tried a hard reset and cleaned the bottom terminal. No luck. My S4 will charge on any other charger. I even cut apart a USB cable and shorted the 2 data lines to trick the phone. Still doesn't work. Im starting to think there was permanent damage to my phone, but this just doesn't make sense because it works on everything else.