Question about power inverters

[notfound]

I am putting together and mp3 box that I am going to put in my wifes car I have it just about done, I just need to get a power inverter and that is it. Now my question is, does the wattage for the power inverter have to be at least the same wattage or higher than the power supply... for example:

Power Inverter : 150watts continous 300 peak watts
Power Supply : 300watts

basically do I need to get a power inverter that has at least 300watts continously or would a inverter like the one listed above me sufficient. Any info is greatly appreciated. Thanks

Please let me know if I have this post in the wrong forum... and let me know where I should post this. Thanks

 

[DIRTsquirt]

I wish I could answer your question.. hehe
I cant offer that I have a 300w peak inverter and powers my p133 laptop. without any problems.
I run a 13" tv vcr combo off of this during late hunting season. without any difficulty.
You running a monitor also?
the thing to do is run an ampdraw with an ammeter. once you get your amps the formula is amps x volts = watts
I for sure would get an inverter that is big enough to provide at least 20% headroom at the continuous rating.

are you using some kinda proggy that loads the songs in a ram drive and plays from the ramdrive.. thus reducing spin time of the hardrive while you are traveling.. I imagine a pothole and a spinning hardrive could spelll disaster.

wish i could be more help if you are using a proggy like the one I described above could you pm with a linky..

good luck

PS if you list the stats of the unit.. I will be doing an electrical analisys next week on my machines to determine how much seti cost me to run... I will be doing ampdraws on my system at full load running seti.
If you are not in a hurry I could post that data near the end of next week

 

[Mark R]

It may work, with a low end system.

The total power taken by the PC system is likely to be less than 100 W (if it's <1 GHz) - you don't mention if it has a monitor (which will need more power).

The other thing to bear in mind is Power Factor. Inverter capacity is NOT rated in Watts it is rated in Volt-amps. They are slightly different. PC power supplies have a low Power factor (about 0.6) which means that if it needs 100 W, it will actually take 166 VA (which will be higher than the capacity of the inverter).

If your system, used a celeron (low speed ideally < 500 MHz, or possibly one of the new 0.13 micron ones), a single drive, and no graphics card (or integrated graphics), then you should easily be able to get power consumption down to below 80 VA.

An alternative option is a PSU with active PFC (power factor correction) - in this case the PF is about 0.95, so a 100 W system will only need 105 VA.