Wiring directly to battery

[daKiNeP5]

I've been reading these boards for a while but its my first time actually posting. I've done searches on wiring things directly to the battery but I'm not completely sure about a few things. My friend has seen what I've done with neon lights to my car and he wanted me to add one to his trunk on his lexus. Problem is that I've never wired anything directly to the battery before. I don't want his car blowing up or catching fire or anything so I figured I should see if anyone here can help. I found a path where I can run the wires to under his hood but I'm not sure about the whole fuse deal. The light he has is that 10" neon tube from walmart and the wire is really thin. I was wondering if it was safe to connect this directly to the battery? Also what type of fuse would I need to use?
Another thing thats been bugging me is grounding stuff. I read somewhere that you shouldnt run your ground wire to the negative terminal of the battery and I was wondering if that was true.
Anyways thanks for taking the time to read this and hopefully someone can answer my questions.

 

[derrick1623]

you'll need at least a 10 amp fuse i would think, to ground it, just use any unpainted part of the trunk, if u have to sand down a little paint...good luck.

 

[gjmoreo]

All you need to do is tap off a 12v source. You could use the lighter socket too, but that kinda sucks - best bet is to "hard wire" - you dont want to use a constant 12v source, but a ignition switch 12v source, this way the tube only comes on when the key is in the ACC or on position.
Do not ground to the neg. battery terminal.
Do as Derrick advised.

 

[daKiNeP5]

I was also thinking of wiring neons in my car also. I just wanted to know if this method would work out. Theres that fuse box in the drivers side footwell so if i unbolt that and find the wires for the windshield wipers or something and connect the positive end to that then the neons will only be able to turn on when the key is in the ignition correct? And after that all I would have to do is put a fuse right after I connect the positive end to the wire from the windshield wiper?
Thanks