AC Inverter not working. Not enough power from car?

[Chapel]

So, today I tried to plug my new laptop into my 140W AC Inverter today and as soon as I plug it in the inverter turns off.
I went out and bought a 300W inverter and the same thing happens.
I tried the 140W in another car and the inverter stays on just fine and the computer works great.
The inverter worked fine last year on the way to waterfest but I have since added an amp and a subwoofer.
Is there a possibility that the amp and sub are draining the available power and the AC Inverter just doesn't have the power?
Im planning on disconnecting the sub and amp and seeing if that works.
Any other ideas as to what is happening?
It doesnt even work with the car on either so its independent of the alternator.

[DanGillan]

i really think it is the amp drawing all that power.... the only solution i can think of to be able to run everything at once is to buy a capacitor to hook up to your amp, in case you dont know what it is, it's just basically a small battery that gets charge from your car battery and powers your amp (somewhat) to conserve battery power.

[Chapel]

the amp isnt on when the stereo isn't on, neither is the sub.
same result when the stereo is off

[UNHCLL]

are you trying all of this with waster alt. bolts and chewed up belts?

Alt might not be fully charging system.

Bring the AC Invert tomorrow and the laptop, we'll try it a few other E30s and see if it does the same.

[AndrewBird]

Matt (With turbo) has an inverter in his car. It was charging his digital camera when I saw it with no problems. He had his hardwired in.

Andrew

[Chapel]

it's doing it in my girl's subaru too.
looks like it might be the ac inverter.