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.

---

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

Trying to use cars for a significant power sources is a waste of time.
A few lights and a radio and that's it.
Oh, wait you don't need an inverter to run those.

On Nov 8, 9:37*pm, "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.

---


Oh, no. Now you've done it. That EA imbecile from the
other thread is probably gonna buy a fire truck now...

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.

On 11/9/2012 7:38 AM, 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.

Yeah, to get constant high power from a car alternator, you need a
bigger alternator. Auragen makes such an animal. It works well, but
isn't cheap. And, for the higher outputs, it does take over the engine
throttle so you have to be stationary. But for use as a backup, that's
not a problem. The one I am familiar with is a 5KW unit. It, along
with its box of electronics, puts out a clean 120 volt true sine wave.
The company installs it in your vehicle. I had one in a video
production truck in my former life.

On Fri, 9 Nov 2012 06:38:47 -0600, "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.


A 2000 watt amplifier will draw PEAKS of 170 at full volume - average
current well less than 100 amps - and 2000 watts is INSANE.

Big thing is a few amps to run the alternator field, another 10-ish
for ignition at full bore, and another 17-25 for EFI including fuel
pump - then add cooling fan, heater fan, and air conditioning clutch.

60 amps will barely keep up.

On 11/09/2012 05:22 AM, Art Todesco wrote:

Yeah, to get constant high power from a car alternator, you need a
bigger alternator. Auragen makes such an animal. It works well, but
isn't cheap. And, for the higher outputs, it does take over the engine
throttle so you have to be stationary. But for use as a backup, that's
not a problem. The one I am familiar with is a 5KW unit. It, along
with its box of electronics, puts out a clean 120 volt true sine wave.
The company installs it in your vehicle. I had one in a video
production truck in my former life.

Or you could just install an additional alternator or two on the same
engine, assuming they could be connected in parallel at some point to
get the desired output current.

Jon

On Fri, 09 Nov 2012 10:27:23 -0800, Jon Danniken
wrote:

On 11/09/2012 05:22 AM, Art Todesco wrote:

Yeah, to get constant high power from a car alternator, you need a
bigger alternator. Auragen makes such an animal. It works well, but
isn't cheap. And, for the higher outputs, it does take over the engine
throttle so you have to be stationary. But for use as a backup, that's
not a problem. The one I am familiar with is a 5KW unit. It, along
with its box of electronics, puts out a clean 120 volt true sine wave.
The company installs it in your vehicle. I had one in a video
production truck in my former life.

Or you could just install an additional alternator or two on the same
engine, assuming they could be connected in parallel at some point to
get the desired output current.


Too much messing around. You can get a 200 amp alt for many cars,
including my '97 Lumina.
Even with the stock 100 amp alt and a good inverter setup it can start
and run a fridge, power some house lighting, etc.
All without breaking a sweat.
Nothing wrong with that as a low watt emergency power source.
You just expect only what it can give.
There's a lot of confusion and false trails about this, but it gets
down to simple math and amp draw.
Here's one list of car component amp draw.
http://www.onallcylinders.com/2012/1...an-alternator/
Your car idles in the driveway.
You don't have the headlights on, or the A/C on, or the stereo cranked
up, or the courtesy and dome lights on.
Because that makes no sense for running your fridge.
Figure ignition and fuel pump use about 5-7 amps.
Figure your cooling fan(s) will kick in for whatever length of time
and duration they do for your car and pulling what amps they pull.
Whatever is left from the alt output goes to the inverter.
I don't want to recalc it, but I think I came up with about 500
available continuous 120v watts at idle for the house.
That was with inverter loss of 15% I think. My 100 amp alt car.
If that's not enough, too bad. Go get more juice somewhere else.
I already decided to stick my head in the sand until the outage hits,
then decide what I'm gonna do. Leaving town is my favorite option.

On Fri, 09 Nov 2012 13:38:25 -0600, Vic Smith
wrote:

On Fri, 09 Nov 2012 10:27:23 -0800, Jon Danniken
wrote:

On 11/09/2012 05:22 AM, Art Todesco wrote:

Yeah, to get constant high power from a car alternator, you need a
bigger alternator. Auragen makes such an animal. It works well, but
isn't cheap. And, for the higher outputs, it does take over the engine
throttle so you have to be stationary. But for use as a backup, that's
not a problem. The one I am familiar with is a 5KW unit. It, along
with its box of electronics, puts out a clean 120 volt true sine wave.
The company installs it in your vehicle. I had one in a video
production truck in my former life.

Or you could just install an additional alternator or two on the same
engine, assuming they could be connected in parallel at some point to
get the desired output current.


Too much messing around. You can get a 200 amp alt for many cars,
including my '97 Lumina.
Even with the stock 100 amp alt and a good inverter setup it can start
and run a fridge, power some house lighting, etc.
All without breaking a sweat.
Nothing wrong with that as a low watt emergency power source.
You just expect only what it can give.
There's a lot of confusion and false trails about this, but it gets
down to simple math and amp draw.
Here's one list of car component amp draw.
http://www.onallcylinders.com/2012/1...an-alternator/
Your car idles in the driveway.
You don't have the headlights on, or the A/C on, or the stereo cranked
up, or the courtesy and dome lights on.
Because that makes no sense for running your fridge.
Figure ignition and fuel pump use about 5-7 amps.
Figure your cooling fan(s) will kick in for whatever length of time
and duration they do for your car and pulling what amps they pull.
Whatever is left from the alt output goes to the inverter.
I don't want to recalc it, but I think I came up with about 500
available continuous 120v watts at idle for the house.
That was with inverter loss of 15% I think. My 100 amp alt car.
If that's not enough, too bad. Go get more juice somewhere else.
I already decided to stick my head in the sand until the outage hits,
then decide what I'm gonna do. Leaving town is my favorite option.
Just make sure you make the decision to leave town BEFORE you burn
out your 100 amp alternator by running it at over 50% for more than
half an hour.

On 11/09/2012 11:38 AM, Vic Smith wrote:

Or you could just install an additional alternator or two on the same
engine, assuming they could be connected in parallel at some point to
get the desired output current.


Too much messing around.
[snip]
Leaving town is my favorite option.

Well there 'ya go!

Jon

On 11/09/2012 10:39 AM, wrote:
On Fri, 09 Nov 2012 10:27:23 -0800, Jon Danniken
wrote:

On 11/09/2012 05:22 AM, Art Todesco wrote:

Yeah, to get constant high power from a car alternator, you need a
bigger alternator. Auragen makes such an animal. It works well, but
isn't cheap. And, for the higher outputs, it does take over the engine
throttle so you have to be stationary. But for use as a backup, that's
not a problem. The one I am familiar with is a 5KW unit. It, along
with its box of electronics, puts out a clean 120 volt true sine wave.
The company installs it in your vehicle. I had one in a video
production truck in my former life.

Or you could just install an additional alternator or two on the same
engine, assuming they could be connected in parallel at some point to
get the desired output current.

Jon

You will quickly run into the limits of the belt unless you add some
pulleys to the crank shaft.

Indeed; my original thought was to use an increasingly longer belt to
drive additional alternators, but your idea of utilizing a
"distribution" pulley (like a pillow block) would only necessitate the
additional belt length for driving one extra pulley (and would, as a
result, be a lot more feasible). Eventually the point would be
reached where the belt was physically unable to handle the additional
load, whereupon it would slip, with the generational capacity of the
system resting upon that limitation.

Jon

On Fri, 09 Nov 2012 14:59:07 -0500, wrote:

Just make sure you make the decision to leave town BEFORE you burn
out your 100 amp alternator by running it at over 50% for more than
half an hour.

Need more numbers. Figure winter time driving A/C defrost on, heater
fan on high, headlights on, parking and sidelights on, rear window
defroster on, radio cranked up, fuel pump and ignition running.
Pretty sure that's more than 50 amps, or close.
I do it every winter for hours at a time. For years on the same alt.
Of course I would have to measure actual amp draw on my car.
Anyway, I low-balled the 120v output at 500 watts, and figuring
inverter loss into it that's still less than 50 amps from the alt.
I've read that a typical alt puts out 60% of rated amps at idle.
If I ever set up an inverter I'd measure draws. You can burn up your
alt if you want to. But you don't have to, and I don't fall for scare
tactics without numbers backing them up.

On Fri, 09 Nov 2012 15:39:28 -0600, Vic Smith
wrote:

On Fri, 09 Nov 2012 14:59:07 -0500, wrote:

Just make sure you make the decision to leave town BEFORE you burn
out your 100 amp alternator by running it at over 50% for more than
half an hour.

Need more numbers. Figure winter time driving A/C defrost on, heater
fan on high, headlights on, parking and sidelights on, rear window
defroster on, radio cranked up, fuel pump and ignition running.
Pretty sure that's more than 50 amps, or close.
I do it every winter for hours at a time. For years on the same alt.
Of course I would have to measure actual amp draw on my car.
Anyway, I low-balled the 120v output at 500 watts, and figuring
inverter loss into it that's still less than 50 amps from the alt.
I've read that a typical alt puts out 60% of rated amps at idle.
If I ever set up an inverter I'd measure draws. You can burn up your
alt if you want to. But you don't have to, and I don't fall for scare
tactics without numbers backing them up.


You will generally run at about 50 amps average - you are not cranking
windows up and down, adjusting power seats, etc constantly while
driving - and the rear defogger cycles after about 3 minutes or so.
The difference between 50 and 70 amps is significant - and between 70
and 100 a whole lot more significant - and add to that the fact that
while drivivng down the road there is a LOT more airflow through the
engine compartment than sitting running the inverter - helping remove
excessive heat.

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.

On Nov 9, 5:59*pm, wrote:
On Fri, 9 Nov 2012 06:38:47 -0600, "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.

A 2000 watt amplifier will draw PEAKS of 170 at full volume - average
current well less than 100 amps - and 2000 watts is INSANE.

Big thing is a few amps to run the alternator field, another 10-ish
for ignition at full bore, and another 17-25 for EFI including fuel
pump - then add cooling fan, heater fan, and air conditioning clutch.

60 amps will barely keep up.

All that is nonsense. Except for lighting, 10 amps will cover
everything.
The alternator is larger to recharge the battery which takes a few
minutes only.
Which is why they have no need to be continuously rated.

On Nov 9, 7:59*pm, wrote:
On Fri, 09 Nov 2012 13:38:25 -0600, Vic Smith









wrote:
On Fri, 09 Nov 2012 10:27:23 -0800, Jon Danniken
wrote:

On 11/09/2012 05:22 AM, Art Todesco wrote:

Yeah, to get constant high power from a car alternator, you need a
bigger alternator. *Auragen makes such an animal. *It works well, but
isn't cheap. *And, for the higher outputs, it does take over the engine
throttle so you have to be stationary. *But for use as a backup, that's
not a problem. *The one I am familiar with is a 5KW unit. *It, along
with its box of electronics, puts out a clean 120 volt true sine wave..
The company installs it in your vehicle. * I had one in a video
production truck in my former life.

Or you could just install an additional alternator or two on the same
engine, assuming they could be connected in parallel at some point to
get the desired output current.

Too much messing around. *You can get a 200 amp alt for many cars,
including my '97 Lumina.
Even with the stock 100 amp alt and a good inverter setup it can start
and run a fridge, power some house lighting, etc.
All without breaking a sweat.
Nothing wrong with that as a low watt emergency power source.
You just expect only what it can give.
There's a lot of confusion and false trails about this, but it gets
down to simple math and amp draw.
Here's one list of car component amp draw.
http://www.onallcylinders.com/2012/1...an-alternator/
Your car idles in the driveway.
You don't have the headlights on, or the A/C on, or the stereo cranked
up, or the courtesy and dome lights on.
Because that makes no sense for running your fridge.
Figure ignition and fuel pump use about 5-7 amps.
Figure your cooling fan(s) will kick in for whatever length of time
and duration they do for your car and pulling what amps they pull.
Whatever is left from the alt output goes to the inverter.
I don't want to recalc it, but I think I came up with about 500
available continuous 120v watts at idle for the house.
That was with inverter loss of 15% I think. *My 100 amp alt car.
If that's not enough, too bad. *Go get more juice somewhere else.
I already decided to stick my head in the sand until the outage hits,
then decide what I'm gonna do. *Leaving town is my favorite option.

*Just make sure you make the decision to leave town BEFORE you burn
out your 100 amp alternator by running it at over 50% for more than
half an hour.

Exactly so.

On Nov 9, 10:23*pm, wrote:
On Fri, 09 Nov 2012 15:39:28 -0600, Vic Smith









wrote:
On Fri, 09 Nov 2012 14:59:07 -0500, wrote:

Just make sure you make the decision to leave town BEFORE you burn
out your 100 amp alternator by running it at over 50% for more than
half an hour.

Need more numbers. *Figure winter time driving A/C defrost on, heater
fan on high, *headlights on, parking and sidelights on, rear window
defroster on, radio cranked up, fuel pump and ignition running.
Pretty sure that's more than 50 amps, or close.
I do it every winter for hours at a time. *For years on the same alt.
Of course I would have to measure actual amp draw on my car.
Anyway, I low-balled the 120v output at 500 watts, and figuring
inverter loss into it that's still less than 50 amps from the alt.
I've read that a typical alt puts out 60% of rated amps at idle.
If I ever set up an inverter I'd measure draws. *You can burn up your
alt if you want to. *But you don't have to, and I don't fall for scare
tactics without numbers backing them up.

You will generally run at about 50 amps average - you are not cranking
windows up and down, adjusting power seats, etc constantly while
driving - and the rear defogger cycles after about 3 minutes or so.
The difference between 50 and 70 amps is significant - and between 70
and 100 a whole lot more significant - and add to that the fact that
while drivivng down the road there is a LOT more airflow through the
engine compartment than sitting running the inverter - helping remove
excessive heat.

If you ever set up an engine on a "rolling road" an external fan has
to be set up to keep the engine cool as there is no "slipstream".

wrote:

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.


A 2000 watt amplifier will draw PEAKS of 170 at full volume - average
current well less than 100 amps - and 2000 watts is INSANE.

Yep. But I have an insane person drive down my street every 30 minutes or
so. (Not the SAME insane person.)


Big thing is a few amps to run the alternator field, another 10-ish
for ignition at full bore, and another 17-25 for EFI including fuel
pump - then add cooling fan, heater fan, and air conditioning clutch.

60 amps will barely keep up.

harry wrote:

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.

I guess you DON'T know how to work a pencil or, for that matter, Google
"automotive+audio+amplifier" which will return many results at or exceeding
2000 watts.

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?

On Sat, 10 Nov 2012 01:28:48 -0800 (PST), harry
wrote:

On Nov 9, 12:36Â*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 Â*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.

On Sat, 10 Nov 2012 01:33:39 -0800 (PST), harry
wrote:

On Nov 9, 5:59Â*pm, wrote:
On Fri, 9 Nov 2012 06:38:47 -0600, "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 Â*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.

A 2000 watt amplifier will draw PEAKS of 170 at full volume - average
current well less than 100 amps - and 2000 watts is INSANE.

Big thing is a few amps to run the alternator field, another 10-ish
for ignition at full bore, and another 17-25 for EFI including fuel
pump - then add cooling fan, heater fan, and air conditioning clutch.

60 amps will barely keep up.

All that is nonsense. Except for lighting, 10 amps will cover
everything.
The alternator is larger to recharge the battery which takes a few
minutes only.
Which is why they have no need to be continuously rated.
10 amps won't come close to running today's car at off idle, running
the alternator.

On Nov 10, 12:59*pm, "HeyBub" wrote:
harry wrote:

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.

I guess you DON'T know how to work a pencil or, for that matter, Google
"automotive+audio+amplifier" which will return many results at or exceeding
2000 watts.

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

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.

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.

On Nov 10, 7:10*pm, wrote:
On Sat, 10 Nov 2012 01:33:39 -0800 (PST), harry









wrote:
On Nov 9, 5:59*pm, wrote:
On Fri, 9 Nov 2012 06:38:47 -0600, "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.

On Nov 11, 4:04*am, harry wrote:
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.- Hide quoted text -

- Show quoted text -

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.

On Nov 11, 10:52*am, harry wrote:
On Nov 11, 12:08*pm, "
wrote:





On Nov 11, 4:04*am, harry wrote:

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.- Hide quoted text -

- Show quoted text -

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.

Well here's a little graph for you. 5 amps for a fuel pump.
And that's running flat out.http://delphi.com/manufacturers/auto...ng/brshls-fp/- Hide quoted text -

- Show quoted text -

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.

On Sun, 11 Nov 2012 01:04:22 -0800 (PST), harry
wrote:

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









wrote:
On Nov 9, 12:36Â*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 Â*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. Â* 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.
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.

On Sun, 11 Nov 2012 01:07:34 -0800 (PST), harry
wrote:

On Nov 10, 7:10Â*pm, wrote:
On Sat, 10 Nov 2012 01:33:39 -0800 (PST), harry









wrote:
On Nov 9, 5:59Â*pm, wrote:
On Fri, 9 Nov 2012 06:38:47 -0600, "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 Â*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.

A 2000 watt amplifier will draw PEAKS of 170 at full volume - average
current well less than 100 amps - and 2000 watts is INSANE.

Big thing is a few amps to run the alternator field, another 10-ish
for ignition at full bore, and another 17-25 for EFI including fuel
pump - then add cooling fan, heater fan, and air conditioning clutch.

60 amps will barely keep up.

All that is nonsense. Except for lighting, 10 amps will cover
everything.
The alternator is larger to recharge the battery which takes a few
minutes only.
Which is why they have no need to be continuously rated.

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

In days of yore five amps would cover the ignition easily.
Modern solid state ignition systems use less.than this.

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

Bigger alternators are fitted to cover all the stupid unnecessary
accessories in modern cars.

On Thu, 8 Nov 2012 23:18:41 -0800 (PST), harry
wrote:

Tch. What drivel.
Automotive alternators are not continuously rated.
You only get the full output at fairly high engine revs anyway.
Why is 20-40 amps needed to run the car?

Trying to use cars for a significant power sources is a waste of time.
A few lights and a radio and that's it.
Oh, wait you don't need an inverter to run those.

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.

harry wrote:
On Nov 11, 12:57 pm, "HeyBub" wrote:
harry wrote:

I guess you DON'T know how to work a pencil or, for that matter,
Google "automotive+audio+amplifier" which will return many results
at or exceeding 2000 watts.

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

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

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.

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.

On Nov 11, 5:59*pm, wrote:
On Sun, 11 Nov 2012 01:04:22 -0800 (PST), harry





wrote:
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.

*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.

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.

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.