current/wattage conversion?

[Smokin' Rubber]

Ok I have a question about 12V current and 100W current.I'm getting an LCD for my car and it is made for 12V use but I already have a 100W application in place (you know what I'm talking about if you ready some of my more recent posts). So do you think that that the LCD would be able to handle to the 100W current or would I have to do more rewiring to get the 12V to the correct place. I know how I could make an adapter for the wires (that would be easy) but I don't want to fry the LCD.

[joatmon]

The inverter puts out 115 Volts alternating current (AC), which is what you rerouted for the xbox. If the LCD is made to run off 12 V direct current (DC) then if you hooked the LCD up to the 115V AC you'd probably fry it.

[Smokin' Rubber]

It's not hooked up to the 115 AC its hooked up to the 112 DC, I rerouted the power from the house outlet so that it goes to the glove box where the cords form teh xbox run to (and it works perfectly as far as I can tell).*Edit*NM lol the LCD comes with a 100W DC adapter so it'll be fine

[Jahntassa]

Wow..okay, i'm confused. There is no 112v DC power in the car, there's 115v AC, which shows up at that AC plug above the shifter. The 100w rating is pretty much only for the AC inverter. Your LCD does NOT take 100 watts worth of power. You can plug an LCD monitor into a 12v camcorder battery and have it run for a while, if it's a 7" or so. You can plug your LCD into any 12v source (NOT the inverter), and it'll work fine without the adapter.

[Smokin' Rubber]

Quote, originally posted by Jahntassa »Wow..okay, i'm confused. There is no 112v DC power in the car, there's 115v AC, which shows up at that AC plug above the shifter. The 100w rating is pretty much only for the AC inverter. Your LCD does NOT take 100 watts worth of power. You can plug an LCD monitor into a 12v camcorder battery and have it run for a while, if it's a 7" or so. You can plug your LCD into any 12v source (NOT the inverter), and it'll work fine without the adapter.Why would a car have an AC outlet.... there is much more risk or shorts as well as frying the fuses in the car because or spike returns from the appliance. As well, I was almost positive that all AC outlets require a ground prong on the outlet as well as on the plug for appliance to help ensure that the spike would not cause damage to your house's electrical systems.And yeah not kidding the LCD doesn't take 100W of energy to run it only requires 9W which is exactly why the adapter (just like all smaller appliances have) has a larger transformer (you know those big block type plugs) right where it plugs in which limits the amount of energy the appliance get so that it does not blow up. I do realize that I could plug it in at another 12V source but the whole point was to be able to run it all to my redirected and modified 100W port in the glove compartment.

[Jahntassa]

Quote, originally posted by Smokin' Rubber »Why would a car have an AC outlet.... there is much more risk or shorts as well as frying the fuses in the car because or spike returns from the appliance. As well, I was almost positive that all AC outlets require a ground prong on the outlet as well as on the plug for appliance to help ensure that the spike would not cause damage to your house's electrical systems.Um...no, not all AC plugs require 3 prongs. Laptop computers, game systems, and small TVs and appliances only need two prongs. (With the exception of some Compaq and other laptop power supplies). Ground is a suggestion, not a requirement, especially not in a moving car. And the inverter is fused with the 12v outlet. You do have a Vibe, right? You know that AC plug up and to the right of the shifter?Quote »And yeah not kidding the LCD doesn't take 100W of energy to run it only requires 9W which is exactly why the adapter (just like all smaller appliances have) has a larger transformer (you know those big block type plugs) right where it plugs in which limits the amount of energy the appliance get so that it does not blow up. I do realize that I could plug it in at another 12V source but the whole point was to be able to run it all to my redirected and modified 100W port in the glove compartment.The screen isn't going to pull more power than it needs. You can plug it directly into a 12v source with no problem, as long as it require a 12v input. The transformer is to step 115 AC voltage to 12v DC. In a DC environment, you would generally only need the transformer as a noise reducer. I still don't understand what you mean by 100w port. The AC plug is rated to power 100w appliances, but everything else in the car is 12v.

[ragingfish]

Rubber:I think you're confusing watts and volts. They're two totally different things.Take a 25W desk lamp bulb. It screws into a desk lamp, which operates on 115 VAC.Now take a 100W recessed fixture bulb. Screw it into the socket, which also runs on 115 VAC. Both bulbs operate on 115 VAC. But if you were to screw that 100W recessed bulb into the socket of the desk lamp (if such a thing were possible, but it's not), you would overheat the wiring for that desk lamp, and possibly cause a fire. Why? Because even though the voltage is the same, the recessed fixture pulls too much wattage, which the thinner wires of a desklamp can't handle.There are two types of current. AC = alternating current and DC = direct current. DC voltage is found in your car, and all small electronic appliances, such as boomboxes, portable stereos, etc. When you use batteries in an appliance, you're providing direct current automatically. When you plug a boombox into the wall outlet, that current is usually converted to DC either in the transformer block on the plug (if equipped), or inside the radio itself. The household-style outlet in the car is ALTERNATING CURRENT. The inverter under the driver seat takes standard 12V automotive power and steps it up to 115 V of AC power. You CANNOT hook up a DC appliance -- in this case, a LCD screen, to AC current directly. You will destroy it! If that LCD needs DC power, take it right from the fuse blocks, or use an AC adaptor to bring it back to DC current.

[Smokin' Rubber]

Quote, originally posted by ragingfish » or use an AC adaptor to bring it back to DC current.I thought I explained in my other post that I was going to use an AC to DC adapter that came with the LCD (hence my description of the big boxy thing on the plug)?So it shouldn't be a problem then right?

[ragingfish]

Quote, originally posted by Smokin' Rubber »So it shouldn't be a problem then right?I'm not an expert, so I don't know.But why do that? Why not just make a custom cord that pulls right off the DC in the car already? Cleaner install.

[Smokin' Rubber]

Quote, originally posted by ragingfish » Why not just make a custom cord that pulls right off the DC in the car already? Cleaner install.Not really a cleaner install (I would have to show you how I have it currently setup). I think it would be uneccesary but I might end up doing it anyway

[Jahntassa]

You can power the LCD using the "boxy thing" (boxy thing = transformer), off the AC voltage coming from your re-routed AC plug. What it comes down to, really, is it's simply a waste of space, an an extra power conversion that's not needed..I guess the best way to put it is that you're taking two people that're in speaking distance of each other, and making them talk through digital cell phones. You'd be converting speech to digital, then digital to speech. So basically...you want to cut out the middle-man. Powering the LCD off the transformer is basically taking the 12v the screen wants, converting it to 120v AC, then converting it BACK to the 12v, meanwhile wasting power in the conversions (yes, transformers and inverters DO take power..)So it's not a matter of you -can't-...it's really just a matter of why -would- you..

[joatmon]

Some of those AC to DC adapter transformers are made with the AC prongs built into the transformer box, such that the boxy part of the thing plugs into the outlet. A "wall wart". The tension on the connections inside the plug is usually good enough to hold the thing in the wall around the house, but in the car you'll have a lot of bumps and vibration. If you plug one of those in to an AC outlet in the car, probably be a good idea to mechanically attach it to the outlet with tape or string or something so that a big pothole doesn't make the plug pull out of the outlet.