On Nov 10, 7:09*pm, wrote:
On Sat, 10 Nov 2012 01:28:48 -0800 (PST), 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.
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.

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.

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.