On Sun, 11 Nov 2012 00:50:08 -0800 (PST), harry
wrote:

On Nov 10, 1:54*pm, "
wrote:
On Nov 10, 4:28*am, harry wrote:









On Nov 9, 12:36*pm, "HeyBub" wrote:

harry wrote:
On Nov 9, 2:37 am, "HeyBub" wrote:
From a blog post:

---

Folks considering inverters should first check their automobile s
alternator capacity to figure out how much they can power long-term
from an inverter without discharging the battery.

Making rough calculations, your Mazda RX-8 probably came stock with
a 100 Amp alternator (at 13.8V) = ~1400 Watts, so anything much more
than that is overkill (not to include peak rating). You can get
aftermarket high output alternators, usually in the 160-200A range;
my older Toyota only has a 60A alternator.

But some of that power is needed to run the car (20-40 Amps), so for
a 100A alternator the best case is 1100W available for the inverter.
These output ratings are at normal driving engine RPMs and at idle
you are lucky to get 75% of the rating (and as low as 50%) so we re
now down to 800W (max, probably lower), which will provide you with
~7A @120V AC, enough to run the refrigerator (130-200W) and more.

You ll need at least a 750W inverter ( peak 1500W inverters typically
have a peak rating 2x the normal rating) to handle the starting surge
current for starting the refrigerator (~1200W) with the extra energy
coming from the battery regardless of how much power your alternator
produces.

To run a 3000W inverter continuously without discharging the battery
you need a 300A alternator, what you would typically find on a fire
engine.

---

Tch. What drivel.
Automotive alternators are not continuously rated.
You *only get the full output at fairly high engine revs anyway.

Can you work a pencil?

Depends on what you mean by "full output." Car alternators are connected to
voltage regulators which hold the output voltage (almost) constant,
irrespective of RPM.

Why is 20-40 amps needed to run the car?

A 2000-watt amplifier will use (at least) 170 amps. Add headlights, a/c fan,
cigarette lighter, and, of course, the engine, and you'll be above 200 amps.

What 2000 watt amplifier is this?
A car needs less than an amp for the ignition circuit.
If you have a diesel car,not even that.

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 won't need anything else whilst you're trying to use your car as a
power source.

You are very uneducated. Best to keep silent.- Hide quoted text -

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

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

You're an idiot, harry. Do you think that GPS/radio/display takes
10W? Think again. It's actually quite like a PC.

You've been wrong about everything in this thread and it doesn't seem
to surprise anyone here. I wonder why that is.