As many of you know, I installed a computer in my car some time ago. While this was fine and dandy in theory, in practice it has been a whole different story. As much as I hate to admit it, ever since I installed the computer it has been plagued with problems. For the amount of money and time I put into the project, its sad that it doesn't do one simple thing: work reliably.

I have traced most of the problems back to one thing: My Carnetix CNXP1900 power supply. The features on this power supply are great: automatic power switching, battery protection, computer standby/sleep, fully automatic, etc. etc. The unfortunate part is that it has never worked as advertised.

Since the beginning I have had nothing but problems with the P1900. First were isolated battery drains. I'd come outside and try to start my car only to find that the battery was completely drained. I researched the problem and learned that I had wired my USB devices incorrectly, and that this was the most likely culprit. I fixed the problem so that the P1900 managed power directly to the USB devices. Still, I would get frequent battery drains.

Eventually I wasted some money on buying a new battery, thinking that might be the problem. But no, the battery still drained frequently. In fact, I'm sitting at home right now, unable to go anywhere because my battery is dead again. I have to wait for it to trickle charge.

Besides the non-working power features, the Carnetix P1900 is just plain shoddy. I've had problems with cables coming out of the backs of the plugs, wires completely ripped out of the backs of plugs under normal stress, and other issues.

Also, the automatic power on (button simulation) worked maybe 5% of the time. The computer would power up by itself when the P1900 sent to it, and then it would simulate a button press, causing it to immediately shut back down. I found I had better success just disconnecting the button press simulation cable and letting it power up by itself (actually I didn't have a choice, since the cable ripped apart several times until it was no longer repairable). Even then, most times the computer will wake up from sleep and then the Carnetix P1900 will inexplicably shut off.

Again, I was told these problems were due to USB devices, so I unhooked all my USB devices and kept testing. I would have the exact same problems. I tested and tested and re-wired and double checked the instructions, browsed the forum, and no matter what I did the P1900 never performed as it should.

To add insult to injury, Carnetix never responded to repeated support requests. The last email I sent them was several months ago, simply asking if they offer a warranty and what it entails. I never got a response.

Even mp3car.com offers a one year warranty on everything they sell (according to their FAQ) but refused to take back my power supply saying it didn't qualify (mp3car has been really cool usually, but that's a but shady if you ask me). This was not stated on the product page or anywhere else on their website (although they might have fixed it by now).

So the lesson kids, is don't buy from Carnetix. Even if you buy one of their newer power supplies and even if they've worked the bugs out, they won't support it or help you when you're having problems.