More on inverters

[trader4]

I would not be focused on just the ignition circuit and doubt there is much difference in current needed for either a gas or diesel engine. A car today isn't just a simple engine like in a 55 Chevy. There are numerous computers, relays, sensors, controls, etc that all are powered when the car is running. Ignition for spark in a gas engine is one component of all that, but only one component. The dash display, console display, etc are all powered for example.

I don't now how many amps a modern car actually pulls when running, but I do know that Harry doesn't really know either.

You think a car today only needs ignition current to the plugs to run? And you're calling others uneducated?

[clare]

Actually, an electronic ignition can require in excess of 5 amps. Some as high as 7 and even more - and is dependent on engine speed.

A motorcycle twin electronic ignition runs 3 to 5 amps

TheMSD 6A performance ignition specs 1 amp per thousand RPM on a 4 cyl.

EFI pumps run 3.5 to 10 amps depending on system pressure and engine HP. The fuel injection system is USUALLY fused at 20 amps - so a good guess is 12-15 amp operating current.

High Beam headlamps are generally 60 watts each - so 10 amps for the pair, add another 10 amps for all the other lights in the car, not counting fog or aux driving lamps. Add another 3.5 nominal for the A/C clutch, and about 10 to 15 for the radiator cooling fan, and 7 to 10 for the heater fan.

[clare]

10 amps won't come close to running today's car at off idle, running the alternator.

[harry]

30 watts of power would deafen in a car. Half a watt is normal for listening to a radio.

[harry]

The relays and sensors take microwatts to power them. A computer, 10 watts, we're not talking a PC.

[harry]

So you're going to be running all this stuff whilst the car's parked on the driveway "generating power"? Heh heh, you ARE in cloud cuckoo land. Better have the demisters on too. And the interior light.

[harry]

In days of yore five amps would cover the ignition easily. Modern solid state ignition systems use less.than this. Bigger alternators are fitted to cover all the stupid unnecessary accessories in modern cars.

[trader4]

I say until you actually measure how much current a modern car draws while idling, you're just speculating. And clearly, that current draw is not limited to the ignition, as you claim. CL came up with a good example, electric fuel pumps. I'll add another one to the list, electronic fuel injection. Then you have electric cooling fans. All that plus the computers, dash displays, etc take power and it adds up. It is NOT an issue of just supplying ignition power and hasn't been for decades.

[HeyBub]

Agreed. But neither point negates the absolute fact that 2000 watt amplifiers exist or that these amplifiers are installed in automobiles.

[The Daring Dufas]

I was stopped at a red light when I felt a disturbing vibration in my gas peddle which made me think there was something wrong with my engine. It turned out to be the bass notes booming out of the deaf brother's fly ride behind me. There are times when the dogs start barking at what sounds like an approaching thunderstorm rattling the windows but it's one of those prematurely deaf morons driving past the house. O_o

TDD

[harry]

A 2000 watt amplifier is the sort of thing you'd find at a political rally or a pop concert. More than say six watts in a car would damage your hearing.

[dpb]

On 11/11/2012 9:33 AM, harry wrote: ...

There are more than just a few who have such from such... :(

[harry]

Well here's a little graph for you. 5 amps for a fuel pump. And that's running flat out.

[trader4]

Thanks for proving yourself wrong. You made the claim that ignition was all that was needed as far as power draw goes. Now that you've recognized that fuel pumps require power, try adding up all the other circuits that are powered when the car is running.

[clare]

Someone asked why a car needs such a big alternator. The 2000 watt stereo won't be run either.

BUT - the fuel injection and the ignition will - as well as the field of the alternator. EFI at 15, and ignition at 3 amps @ 3000RPM, plus the alt field and the engine cooling fan- so 35 amps,more or less, with all other accessories and lights shut off.

[clare]

No they don't. They produce a hotter spark - which requires MORE current -

[coach]

But what about those of us who need to run a portable electric chair? You never know when you will want to give idiot driver a dose of capital punishment, right on the road.

[gregz]

In the upper ranges low power can create a lot of SPL. When your using low efficiency woofers hundreds of watts may be needed. A 200 wats system can be very common. I had a good system installed on my old Dakota, after tweaking everything.

A CES show I went to had a special brinks like truck fitted with 22- 2000 watt amplifiers. 44000 watts ! sure, I'm sure it might b a problem actually using the thing. Looked cool.

Greg

[HeyBub]

Whether they damage your hearing or are the same output is used a pop concert does NOT negate the fact, which you seem to continue to deny, that such devices ARE installed in more than a few automobiles.

[trader4]

That is by far the best example of a good size load that is present when the car is running. Harry will probably try to tell us that isn't real or necessary either.