Wiring a usb charger directly into 12V DC?

superman22x

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Hey all, I have a question. I am thinking about grabbing a mount for my phone on my motorcycle so I can use it as a GPS. Or just a mount for my regular GPS. My question is about wiring in a charger. Being a motorcycle, it doesn't have a cigarette lighter plug. I was thinking about cutting a mini and/or micro USB cable and wiring it directly into the 12V system. Would this carry too much current for a GPS or Phone though? I could wire in a cigarette lighter plug, but that would be bulky and there isn't much room on the bike, being a naked bike.
 
usb is 5V. If try using 12, you'll destroy whatever you try to charge. Get one of those usb car chargers, crack the case open, then wire just the board into the 12V supply. That'll give you a voltage regulated usb socket that you use to charge whatever.
 
Many motorcycles use 6 volt batteries. Be sure you know what voltage your motorcycle provides.
 
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Many motorcycles use 6 volt batteries. Be sure you know what voltage your motorcycle provides.
I would have thought most modern day motorcycles would use 12 volt, but as you say there will be the odd 6 volt which in he could wire the USB directly as 1 volt difference would not matter that much from 5 volt.
 
You could open a cig adapter and solder on some wires to connect to the bike's harness. I'd go for an ignition hot lead ( on when the key is in start position or acc position ). Since the cig adapter's don't cost all that much might be a prudent way to go.
Have you considered how much high frequency vibration there is on a bike? Mostly on the handlebars. As atested to by numb hands on a long ride.
 
Yeah, the bike mounts usually have some sort of foam or something built in to reduce vibrations. I don't get numb hands on long rides though really. Mine isn't too bad.
 
I would have thought most modern day motorcycles would use 12 volt, but as you say there will be the odd 6 volt which in he could wire the USB directly as 1 volt difference would not matter that much from 5 volt.

Not a good idea. I'm not totally sure how a motorcycle would be set up, but i've heard of people frying things by hooking directly into electrical systems on cars, boats, etc. because the alternator created a huge power spike for one reason or another. The engine starter also has the potential to create some weird issues. Something regulated and well isolated is definitely the way go if you're connecting to any sensitive electronics.
 
if you only want 5v, then why not buy a 5v regulator to connect to the bike?

from there you have two choices, either wire it directly to the main harness, or, put a new fuse in the fuse box in a spare slot and create a new circuit. (second option is more work, but much more flexible.)

after that, I'd stick a USB socket on the end, not just have a mini usb cable coming out of the frame somewhere!

or I'd do away with the cheap regulator and just sick a normal lighter socket on the bike, that way I could use other gadgets.
(for example I can use my USB lighter adapter to charge either my iphone or blackberry), they only need 5v supplies, but if I was out and had taken my laptop, then I could use my little inverter to power that.

There must be some panel on the bike that you could stick a waterproof accessory socket on? (that's the other problem with just sticking a USB socket on it, you really want it to be waterproof!)

(I'd say that most bike electrics are 12v nowadays, you'd have to have a really old or really obscure bike to only have 6v)
 
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