If you have a system running with an inverter and it works, please read!

**Sivion** · 08-01-2004, 05:31 PM

Hey guys,

Ok, I am right on the brink of getting everything to work properly. But there is this terrible plauge in my system. It is noisy! If only I could get rid of it. Now, I know it's from the inverter because if I plug the system into house current, the image is clear as can be. As soon as I hook up the inverter, BAM there is the noise. Here is what I have tried so far.

1) Grounded PC Case to Car Chasis (this actually got rid of 1/2 of the noise)
2) Grounded the inverter chasis to car chasis at the same point as PC and to a different spot on chasis (although it was with a 18 AWG wire)(no change)
3) Grounded the negative power cable that feeds the inverter to the car chasis (no change)

I have a tripplite 375 Watt inverter. So, if anyone can give me a clue to what might be wrong, please tell me. I am going crazy! And as I stated in another post, I would go DC-DC in a heartbeat if there was a 300 Watt version or even a 250Watt version.

**Sivion** · 08-01-2004, 05:38 PM

By the way, would a true sine wave inverter eliminate a lot of these kinds of problems?

**no1knows** · 08-01-2004, 05:40 PM

where is the noise? sound? screen?

**l9nux** · 08-01-2004, 05:45 PM

I too had this problem, and found that it was because inverters use a modified sine wave and computer power supplies are very sensitive to this. I had the problems you describe with my 600w inverter, the screen was slightly fuzzy and the buzzing sound drove me mad.

There are 250w DC-DC power supplies available which is what I had to do in the end. I bought mine from CarTFT.com (http://www.cartft.com/shop/catalog/gl/13). They're based in Germany but do shipping all over the world.

Yes a true sine wave inverter would also do the trick but they cost a lot of money! $$$$$

After doing a bit more research, a good regulated DC-DC power supply seems to be the best choice. Otherwise with an inverter you're converting DC to AC then back to DC again for the motherboard. This is not very efficient, especially when it's not running at a clean 50htz.

I hope this helps, I know how frustrating it can be!

**Sivion** · 08-01-2004, 05:54 PM

Originally Posted by no1knows

where is the noise? sound? screen?

Woops sorry, it's all in my LCD display.

**Sivion** · 08-01-2004, 05:57 PM

Originally Posted by l9nux

I too had this problem, and found that it was because inverters use a modified sine wave and computer power supplies are very sensitive to this. I had the problems you describe with my 600w inverter, the screen was slightly fuzzy and the buzzing sound drove me mad.

There are 250w DC-DC power supplies available which is what I had to do in the end. I bought mine from CarTFT.com (http://www.cartft.com/shop/catalog/gl/13). They're based in Germany but do shipping all over the world.

Yes a true sine wave inverter would also do the trick but they cost a lot of money! $$$$$

After doing a bit more research, a good regulated DC-DC power supply seems to be the best choice. Otherwise with an inverter you're converting DC to AC then back to DC again for the motherboard. This is not very efficient, especially when it's not running at a clean 50htz.

I hope this helps, I know how frustrating it can be!

Thanks so much for the input! Hmm, that supply would be perfect except one thing. I have a Micro-ATX case and that supply would not fit in there. Grrr...Anyway, I found a cheap pure sine wave inverter that may work. Tell me what you think about this.

Here

**owenjh** · 08-01-2004, 06:03 PM

Is it possible to try a different brand of inverter? my coleman 400watt makes a crap load of noise while my Tripplight makes none.

**Sivion** · 08-01-2004, 06:05 PM

Originally Posted by owenjh

Is it possible to try a different brand of inverter? my coleman 400watt makes a crap load of noise while my Tripplight makes none.

I have a Tripplite. I was thinking of getting a pure sine wave inverter...Found one for just over $100.00, 300 Watt. Dunno though.

**grahamrb** · 08-01-2004, 06:09 PM

where does your VGA cable run in relation to other power cables. You should not run the VGA cable next to power cables. Also, what are you powering the screen from? the pc psu or direct off the car battery?

**owenjh** · 08-01-2004, 06:11 PM

hmm, Maybe its the higher wattage inverters that make more noise then. Its a risk your going to have to take, if you want to try a pure sine wave, go ahead. Whereas you could just buy a DC-DC power supply for a bit more. But in the end you will lose if the puresine wave doesn't work.