Originally Posted by Smiert
I'm trying to figure out what the best way to implement a hardwired charger.. more specifically in terms of getting the most mA as I can. What I understand is that when the data pins on a USB charger are floating, the phone requests only for 500mA. When the data pins are shorted, the phone requests for 1A (or 1000mA). On any decent 5v ciglighter /wall outlet phone charger, I understand that the charger shorts these data pins, allowing for that full 1A charging capacity.
I plan to use one of these ebay 12v to 5v converters:
..and splice a standard micro-usb connector to the 5v output, also connecting both data wires together.
If I understand this correctly, would this provide 1A to the phone? Does anyone see any implications?
In theory it should work OK.
I would recommend a few things. Make sure that dc-dc converter is easily accessible if you need to check it or smell a smoke in the car. Don't bury it too deeply where you will have to take too many things apart to get to it. I made plenty of mistakes in the past where years later wire cracks or connector is not making a good contact and I have to take the whole damn thing apart to get to it
Also, I would STRONGLY recommend to add in-line blade fuse, like this: http://www.ebay.com/itm/Waterproof-P...item3f2dc85fa3
The last thing you want is to damage your phone if you get some in-rush spike. DC-DC converter looks ok, but you never know what could go wrong if it overheats and something shorts out. At least you will have a fuse to protect your 5V power supply line going to the phone. And since blade fuses are replaceable, you just pop in 1.5A or 2A, obviously don't use 10A that comes with it.
Once you done, comeback and post some DIY pics!!!