car pc surges on ignition start

Get an inverter that works to a lower voltage (eg, 8 or 9V, maybe 10V depending on your the vehicle's electrical quality, or a proper PC car supply, or a new or bigger battery (more cranking Amps), or consider a dual battery with a battery isolator - popular with PCs & big audio etc to ensure cranking power remains.

I have a red top 800/1000 and I kinda don't want to get a second battery just for that PC seems a bit extreme .i was thinking a battery isolator. So from my knowledge its two positive leads source to device and a trigger wire. You think a relay would help this situation. 1993 sdv

Alpine 4x6 6x9 5 1/4 swr-10d4

alpine v60

12.5 VGA flip down

Nettop pc w/10" touch screen

78nova

5-re audio 5x7 ,10" sub &

Xtx-500.5

"Take the faceplate off get the jumperpack"

I dread to think how you are switching the inverter (unless it has its own On button) - a relay IMO is essential. Plus having it powered direct from the battery, and with a ground to a substantial body section or the battery - not a flimsy screw or a thin or separate body panel. The chassis or other "frame" is best (or the engine or battery). You are probably suffering an excessive voltage drop.

its not on all the time Nd its a 300 watt intvertor and its grounded to the wheel well as for a relay I will have on eventually. But for now j just use the button on the imvertor1993 sdv

Alpine 4x6 6x9 5 1/4 swr-10d4

alpine v60

12.5 VGA flip down

Nettop pc w/10" touch screen

78nova

5-re audio 5x7 ,10" sub &

Xtx-500.5

"Take the faceplate off get the jumperpack"

Fine, but at max output, it still takes about 30A. It's probably worse than cranking with high beams on. Check the voltage drop from the inverter's +12V to the battery +12V, and its GND/chassis to battery-.

Yra ur right its idlin at 13.5;and it went to 13.1-13.31993 sdv

Alpine 4x6 6x9 5 1/4 swr-10d4

alpine v60

12.5 VGA flip down

Nettop pc w/10" touch screen

78nova

5-re audio 5x7 ,10" sub &

Xtx-500.5

"Take the faceplate off get the jumperpack"

13.5 is ok for engine/alternator idling though higher is common. Older alternators or higher loads can cause a lower idling voltage. The battery should be charging at 13.8 to 14.4V normally, though Optima usually specify higher. If you mean the inverter voltage with load and no load, then 13.5 means you have the engine on (alternator charging) unless the battery has just been recently recharged, and you have a 0.2-0.4V drop (at normal or full load) which is ok. So if your battery drops to 10.5V when cranking, the inverter gets 10.1 to 10.3V.

True but I did have the headlights on the radio on and I have some amps hooked up. I the car was already on so I just turned the invertor and went for it .I have a built in voltmeter I installed so it was effortless on my part1993 sdv

Alpine 4x6 6x9 5 1/4 swr-10d4

alpine v60

12.5 VGA flip down

Nettop pc w/10" touch screen

78nova

5-re audio 5x7 ,10" sub &

Xtx-500.5

"Take the faceplate off get the jumperpack"

I see an aditional problem here, too... You have a 300W inverter. I certainly hope your PCs power supply is rated at 250W or less. PC power supplies are rated on their output power. Output power, times their efficiency, equals input power. 300/85%=345 watts in, if you have a 300 watt computer PSU. You are already overloading your 300 watt inverter by 15%. What are all of the components in your PC? CPU and graphics card are the biggest power hogs in a modern PC... Did you use a PSU calculator to figure your total PSU needs?It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."