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.
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 11/09/2012 10:39 AM, email@example.com wrote:
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.
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.
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 14:59:07 -0500, firstname.lastname@example.org wrote:
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
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 Nov 9, 5:59 pm, email@example.com wrote:
All that is nonsense. Except for lighting, 10 amps will cover
The alternator is larger to recharge the battery which takes a few
Which is why they have no need to be continuously rated.
On Nov 10, 7:10 pm, firstname.lastname@example.org wrote:
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.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.