OK... Has anyone installed a PC behind the dash? I am, but I am new to electrical wiring.

Here is the info:
I wired a 10 guage wire directly to the battery with a 30-AMP fuse under the dash. I was told a 30-AMP fuse is what is generally used for cigarette lighters.

After the fuse, I have an on/off switch to kill the power before going to a dual cigarette adapter where the touch screen monitor adapter and 200 watt power inverter for the laptop plugs in to. I did this so there is no draw from the battery when I do not need to use the PC.

The power works, but the power inverter I am using shows an decline in Volts, and after about 30 seconds, the low voltage alarm sounds... plugging in the laptop or the monitor by itself is fine, but not with both.... Also, the monitor is designed for car use.

My battery is fully charged and I have no issues starting the car.

Questions:
Do I need a higher rated fuse? If so, what Amps are generally used in newer cars for cigarette lighters?

Or... do I need a higher gauge wire?

Thanks for your time...

Aaron

Also, if anyone is wondering... here is what the dash looks like:

http://www.dictationsolution.com/65ElCamino/10.jpg

What is the AMP output of your Alternator. If you only have a 67 amp alternator you may not have enough AMPS.

Might be the 200watt power inverter isn't big enough.

Skeetfreak - Good question about the alternator... i dunno... I bought at Car Quest a few months ago. I will look in to that. Thanks!

Theelcaminofactory - As for the power inverter... you might be on to something... Although 200 Watts is enough to power a 20V 2 AMP power supply (40 Watts), I just read the specifications and it states 160Watt, 1.4AMP Continuous. Even though 160Watts is enough... 1.4AMP seems to be too low. I will return this power inverter and try out another that is rated higher. Thanks!

Thanks again, and I will post what I find out.

A standard 63 amp alternator should have no problem running that little inverter. The #10 wire is certainly big enough, and good for 60+ amps. Could be that the alternator has one bad diode, which under normal conditions will keep up, but not with extra loads like you have, or the built in voltage regulator may not be keeping the buss voltage up where it should be. If you remove the alternator, some auto parts places can test it for you.

Thanks for your replies...

I had time to try out a different power inverter and it appears to work and does not 'overload'... I had it working for about a week, but when I actually needed to use the computer for GPS yesterday to go to a job site, the laptop intermittently lost power...
Fortunately, I kinda remembered the streets from the GPS map before the power died, but it is a little frustrating. Maybe there is a wire loose...

BTW.. I don't think there is a built-in voltage regulator... I thought it was external... and, when I bought this alternator, there was a note inside the box indicating that modern-day alternators are not built like they used to be because of emmissions restrictions...

from my understanding, my alternator will keep up the battery while the car is running, but not recharge like the originals should...

any ideas on this? I have the original alternator (that is sitting on a shelf because it is bad)... I was thinking about one day rebuilding this alternator if, in fact, this is the case with modern-day alternators.

Oh... and I probably should have stated this before since it might rule out the alternator altogether, but the 10-amp wire is going staight to the battery (Like how power for sound systems are hooked up). And I do have a fuse to prevent damage.... sorry for not mentioning this before.

Aaron

So you have an in-line fuse coming off the battery(within 18 inches?) and a 30amp fuse on the block under the dash, correct? How many amps is the in-line fuse?

Not really... just a 30AMP fuse under the dash... what does the inline fuse do?

Thanks

Aaron

Okay... I am trying to think back to the time everything was working til now...

The major change I made was connecting the power steering... This was done on Friday night. But I can't see how this will cause a problem with the power coming from the battery.. and the power steering has its own separate belt than the alternator.

I know my computer system was pulling enough power a week ago... and the battery is fully charged.

I just tried a different switch rated for up to 50amps and that changed nothing.

... still thinking...

Not really... just a 30AMP fuse under the dash... what does the inline fuse do?

Thanks

Aaron

You said you had a wire straight to the battery like how a sound system is hooked up. Then you said, "And I do have a fuse to prevent damage"...so from that I was picturing an in-line fuse holder like this...

http://img.photobucket.com/albums/v107/92283/ec7five/31dfIJCcc1L_SL500_AA300_.jpg

Also, you referred to it as "10-amp wire" so that led me to believe you might have a 10-amp in-line fuse. But looking back I think that was just a typo, right? You meant to say 10-gauge wire?

Where did you ground your circuit to? Your postive supply lead is more than sufficient (12 ga would have worked just fine too). I'd suggest running a ground wire directly to the battery or to a better ground than some piece of metal behind the dash.

And in regards to the fuse... if you were drawing more amps than its capacity, it would have blown completely, not cause intermittent failures.

lol... I did mean 10-gauge... sorry. I do not have it exactly like the sound system... just the fact it is conected directly to the battery... I do have a sound system with that type of inline fuse near the battery I set up a couple weeks ago though.. that system is working just fine (separate wire of course). Sorry for the confusion.

Thanks for the grounding suggestion... I will check that out when I get back home... I am using what was a loose ground wire (dangling under the dash) and it gets lost when it goes in the wire harness cluster... For S*'%$ and giggles, I will make a new ground wire and give it a try. Thanks!

Thanks for the grounding suggestion... I will check that out when I get back home... I am using what was a loose ground wire (dangling under the dash) and it gets lost when it goes in the wire harness cluster... For S*'%$ and giggles, I will make a new ground wire and give it a try. Thanks!

Your ground should be of the same gauge wire as your supply - otherwise, you may end up overloading one of them.

Let us know how that turns out.

Might be the 200watt power inverter isn't big enough.
I agreed with this..I have an inverter thats rated a 300watts,works great.I like it for camping,out in the woods.as a matter of fact,I just go done with it ,when I replace the head on my Elky.I'de ckeck this out first.:poke:

lol... I did mean 10-gauge... sorry. I do not have it exactly like the sound system... just the fact it is conected directly to the battery... I do have a sound system with that type of inline fuse near the battery I set up a couple weeks ago though.. that system is working just fine (separate wire of course). Sorry for the confusion.

No worries. Yeah, I was just confused on how you had it setup.

It sounds like you've got the power wired up right, but I agree with ssr71 about the ground. Even if that's not the cause of this problem, it could still cause other problems later on. Who knows, that ground wire you are using now may be corroded or the termination point could be loose or rusted. It's best to be sure you have a good clean ground.

Well, I installed a new ground wire and it works! Thanks for the suggestion.. to recap the problems and solutions:

First, the power was working for the monitor, but not the laptop... ended up being the power inverter not giving enough amps (1.4Amp when the laptop needed 2Amp.)... After swapping the inverter, both monitor and laptop worked... for a while.

Then, I had intermittant issue that was resolved by installing a new ground wire...

ssr71 and Low75 - It does seem that old ground wire was too old, or maybe because it was not the same gauge as the power wire, than I caused damage to the ground... in any case, I learned something about wiring today, and thanks for your help.

Oh .. one more thing .. The wiring is 10 gauge, but the fuse unit came with a 14 gauge wire... does this mean I should use a 14 gauge ground wire? I installed a 10 gauge ground wire... or does it not matter that much? Or, should I just find a fuse unit with a 10 gauge wire?