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View Full Version : Hardwiring 12V charger directly off battery? Help pls



boomer27
09/08/2011, 12:25 PM
I am adding a few extra 12V accessory chargers inside my VX and am a little unsure of where to tap off the battery power. Should I attach the positive wire directly to the battery terminal (under the hood) or use a wire behind the dash? I am looking to add 5 of these 12V chargers (some in front/rear) and want them to not turn off with the car so that I could charge things when the car is off. Each 12V charger will have its own switch that can be turned off via a switch panel I am making and will mount inside the car. I am also going to add an additional dome light in the rear using the same method. Do I need to add a power cable for each 12V charger with an inline fuse or can I run a single cable from the battery to the interior and use it as my + line? Thanks!

tom4bren
09/08/2011, 01:56 PM
It really depends on what you are going to use those 12V ports for. If it's just for charging batteries then it would be best to run heavy guage wire directly to the battery terminal. If you are going to be running some high tech electronics that may not like a noisy source then you need a filtered line.

It sounds like you would like to only do the job once & want it done right the first time so I suggest that you go for all the above.

Run a fused heavy guage wire directly from the battery & add a BFC (big friggin capacitor) between it and a good ground. From there you can tap off to any number of 12V outlets that you feel you need.

rsteinmetz70112
09/08/2011, 02:09 PM
Please provide technical information on BFC

tom4bren
09/08/2011, 02:26 PM
Read this:

http://www.caraudiohelp.com/car_audio_capacitors/car_audio_capacitors.htm

You probably don't need to filter the line but it doesn't hurt to do so. The car audio section at WalMart sells them or you can get them at most electronics stores.

eternal21
09/14/2011, 10:17 AM
I did this myself a few months ago. I ran one positive and one negative from the battery to the inside the cabin and attached each one to one of these:

http://www.parts-express.com/images/item_large/265-800_l.jpg

From there, I attached one of these
http://infinitemotion.net/mp/vx/interior/av/3volt1.jpg

(after I trimmed up the sides of it) and put it in my console and then used 2 of the remaining positions on the distribution block to put a 12v accessory switch on the rear of the armrest console and the other in the passenger's side rear compartment @ the back of the truck.

http://infinitemotion.net/mp/vx/interior/poweroutlet1.jpg

http://infinitemotion.net/mp/vx/interior/poweroutlet2.jpg

Breezy
09/14/2011, 11:03 AM
Where did you get that gold looking terminal block????

JAMAS
09/14/2011, 12:16 PM
I am also going to add an additional dome light in the rear using the same method.!

For the dome light addition, just tie into the power that is provided to the current dome light. That will allow it to be managed through the same 10amp fuse as the dome light and map lights.

MSHardeman
09/14/2011, 01:12 PM
For the dome light addition, just tie into the power that is provided to the current dome light. That will allow it to be managed through the same 10amp fuse as the dome light and map lights.

That's what I ended up doing. Just tapped into the wiring for the exisitng dome light, ran the new wires across the top of the headliner, then spliced them into the additional dome light. Now both of them come on, step down (I have LED bulbs in them so the light level doesn't fade out), and turn off together. I can also tap them on/off as necessary.

Nice job on getting the additional accessory plugs in, by the way.:thumbup:

eternal21
09/14/2011, 02:28 PM
Where did you get that gold looking terminal block????

The distribution block? You can pick that one up from parts-express.com. I actually have the dual distribution block that looks like this:

http://webrevolutionary.com/price/img-large/power-ground-distribution-block-dual-4-8-gauge-ps128_110411233194.jpg

You can pick it up off eBay.

mdwyer
09/14/2011, 09:04 PM
We talked about it before at this post. (http://www.vehicross.info/forums/showthread.php?t=18430) You can also see my mods in this picture (http://www.vehicross.info/gallery/showphoto.php/photo/9467/ppuser/2679). I have big wire coming directly from the battery, going to a hefty fuse block that you can just see between the accumlator(?) and the fuse box. After that, it continues to the back, across the back of the engine, and through the grommit behind the gas pedal.

I recommend the thickest wire you can afford, and the shortest run you can manage.

You might be able to cheat and only run a positive wire, and use the frame as your ground.

There's a lot of space in the 'hump'. Most of us put in extra sockets there.

I recommend against using cigarette lighters as plugs in general. If you're going to be pulling significant amps, you should really be using something like Anderson Power Pole connectors.

Breezy
09/15/2011, 04:06 AM
What is the "hump"?

mdwyer
09/16/2011, 05:52 PM
What is the "hump"?

Below the stack of audio equipment is a little domed cover. The CPU sits behind it, but most of that front cap is nothing but air. This install (http://www.vehicross.info/forums/showpost.php?p=201683&postcount=8) put a socket at the below that. I put mine in the side of the hump.

http://www.vehicross.info/gallery/data/500/thumbs/100_0924.JPG (http://www.vehicross.info/gallery/showphoto.php/photo/9466)