A thousand watts is 85 amps at 12 volts. Most automotive alternators will fry
if you try to run them at that level, though some heavy duty truck
alternators will handle 1000 watts continuous. Your typical car alternator
will put out 50 amps at 14 volts at 4000 RPM, which is above engine idle. You
can retrofit a heavy duty 150+ amp alternator with a small pulley to make it
spin faster, but modern cars with their tight engine well and serpentine
belts make that a PITA. It would be easier to just get a 3 hp lawnmower
motor, mount a heavy duty alternator and a battery, which would give you 1000
watts easily while running the engine at moderate speed.
And an engine from a tiller or snowblower or chipper will work a LOT
better with the cast iron flywheel instead of the aluminum flywheel on
most rotary lawn mowers. Using a rotary mower engine you will need a
big heavy pulley to act as a flywheel or it will be VERY HARD to
On Thu, 01 Nov 2012 17:05:45 -0400, firstname.lastname@example.org wrote:
That is true. There is virtually no flywheel on a lawn mower engine,
they depend on the blade to be the flywheel. I couldn't even keep a
regular deck style mower running without the blade.
The engine on my redneck 12v generator is from a worn out pressure
washer. The Honda engine will run for years more.
If you can set up the pulleys correctly to get a small liquid cooled
engine to run at 1800rpm and spin the generator at 3600rpm, you will
wind up with a very quiet, reliable genset. A heavy flywheel could help
but I suspect the mass of the armature would be enough to keep power
output steady. I installed a lot of generators in homes and businesses
back in the 90's after a major storm upset the power grid in my area and
my favorite gensets and the ones that had the fewest problems were those
that had liquid cooled engines running at 1800rpm. The 3600rpm
gensets with air cooled engines are called "screamers" by my suppliers.
Yes, I know all about insulated sound dampening enclosures. ^_^
When you write "small", are you referring to a small block V8? The 10kw
Generac units I installed had a 4 cyl Turkish Fiat liquid cooled engine
running at 1800rpm. That speed gives 60 cycle AC power from a 4 pole
generator. The 2 pole generators run at 3600 rpm. The 1800rpm speed lets
the genset respond well to changes in power demand and electric motor
start loads. I think it takes something like 1.5hp per kw to run a
genset so a good sized engine would be needed to get that kind of power
at idle speed. O_o
On Sat, 03 Nov 2012 23:57:24 -0500, The Daring Dufas
Im thinking more along the lines of a Pinto engine or similar. When
one simply changes the pulley sizes...an idling engine can spin a
genny at 1800 rpm easily. How many hp is the typical small engine out
of a Saturn or Pinto or similar?
the little 1.9l Saturn engine is 85hp out of the box. At idle...how
long will it run on 5 gallons of fuel? 10-15 hours or more?
And they can be had very very cheaply out of wrecks and other sources.
A buddy of mine built one using the HF 10kw gennhead and a Pinto
engine. It runs for days on a 20 gallon gas tank. At something like
What is he using for a speed governor to keep the frequency stable? I
know there are a lot om OEM parts used to control idle speed on modern
vehicle engines that could be used to make your own governor. The HF
generator could be directly coupled to a small engine running at 3600rpm
using a Lovejoy coupling. The specs call for 16hp for full output so I'm
wondering if you could couple it to the existing pulleys
on a small 4cyl auto engine keeping the bell housing, flywheel and
starter to make things easier. Of course many modern vehicle engines
don't have a simple ignition system with a distributor and coil, so what
could you do there. I know an old Pinto engine didn't have an ECU
but a simple, possibly electronic ignition with distributor and a carb
which would make for a easy conversion to a stationary engine. My old
89 Dodge van has an engine control computer and TBI which could be used
to build a stationary engine for a generator but I'm wondering about the
new super whiz bang computer controlled engines of today's vehicles? O_o
On Sun, 04 Nov 2012 01:43:57 -0500, The Daring Dufas
Keep in mind..that 3600 rpm engines are using 4 times as much fuel as
a 800 rpm engine. Which is why the good gensets only run at 1800
rpm. They took subsized engines, hooked them up to a genny and run
them hard in order to keep the hp ratings up. Which works..but its
hard on the engine and hard on the fuel bills.
The new whizbang engines do exactly the same thing with the new
computers and they can be yanked out by the roots and installed on the
standby, though its a bit more complicated because so few of them have
a distributor anymore. Hence my suggestion about older engines with a
distributor for the hamhanded or those without a decent shop manual
for the engine/vehicle in question.
Gunner,a Pinto 2300 peaks at 96 ft lbs at 3000 RPM
At 800 RPM it would be doing VERY well to put out 55 ft lbs.
Not likely it could run a 10Kw genny at full load.
With proper modification you might get the torque up to 75 or 80 ft
lbs. That would give you 12 HP. JUST, possibly, enough to run a good
10KW genhead at full output, and take over a gallon an hour to run, so
2 days at close to full power on 20 gallons is believeable. Running at
less than half output might increase run time by 25% if he is REALLY
On a later model engine 800 RPM could possibly be controlled bretty
well under low load by the idle air speed control after it got warmed
The same engine, running at 1800 RPM would put out about 90 ft lbs,
for 30 HP - and running a 10Kw generator head at full output would use
about the same amount of gas because the efficiency of the engine
would be higher.
The Saturn 1.9 is 85HP at 5000 rpm in original form, and 100HP at
5000 with multiport injection.
Torque at 2400 is 107 and 115 respectively.
Assuming 80% torque is available at 1800 RPM, the early engine would
produce [ (.8X107)X1800/5252] ).33 Hp
The multiport engine, under the same assumption, would produce
[(.8X115)X1800/5252] = 31.53 HP
Assuming 80% of maximum rated torque on an engine without variable
valve timing is being quite generous, from my experience.
I'd call 25 and 27 HP pretty realistic.
Also, idle consumption and full load consumption at 1800 RPM have
absolutely nothing in common. Specific fuel consumption at 1800 RPM
MAY aproach 0..4 per HP Hour. That would mean ABOUT 10 lbs per hour
for the low powered engine. At 6 lbs per american gallon of regular
gasoline, we are looking at just under 1.5 gallons per hour, so about
3.3 hours at full load - of approxemately 15 KW with an average
generator head and a reasonably well set up belt drive.
At anything less than full output, the efficiency would drop quite a
bit, so half load MIGHT give you 5 hours of running.
Take off the OEM fuel injection system and replace with a custom
tuneable unit, and retime the camshaft to move the torque peak down
closer to the running speed, and you could perhaps improve efficiency
a bit and squeeze, say, 7 hours at half load out of the system.
On Sun, 04 Nov 2012 14:44:03 -0500, email@example.com wrote:
And if its run at an idle with say...4kw load? 15kw is a hell of a
loadout. I dont pull but 2kw with just the basic...CF lights, reefer
motor, and a TV or radio, plus the blower for the gas furnace. Make
that 2.5kw on furnace startup.
Ill have to see if I can get ahold of Gene, he documented his usages
pretty well and I know he runs his homestead on that engine/genset for
about 4 days on 20 gallons of fuel. At an idle.
My genset here at the homestead is a 4kw Onan and it runs everything
nicely, including the popcorn popper (grin) on about 1/3 gallon an
hour with everything running balls to the wall. Its an 1800 rpm twin
cylinder motor out of a wrecked motorhome.
Which btw..is another good place to find gensets.
Actually about the BEST place to get one - particularly if you want
dual fuel (propane/gasoline) Take a 12HP twin (at 3600 RPM) and run
it at 1800 RPM as a 6 HP engine on a 4Kw Generator head and it is a
long life unit - particularly with a full flow oil filter set-up.
The liquid cooled systems are significantly quieter than air cooled -
and a lot of the higher end motorhome units are moving to liquid
cooled. More expensive though.
On Sun, 04 Nov 2012 14:44:03 -0500, firstname.lastname@example.org wrote:
Oh...I went to sleep one night with my 3.0 Ford Ranger idling out
front and didnt remember it was running..and 2 days later, got ready
to go to work...walked out..and my truck was running. Used about 3/4
of a 14 gallon tank of gas.
Just a heads up.
There was a well known party girl here in town who'd get sloppy drunk
and not remember where/what went on many nights. She left her little
Toyota idling outside of the local hangout over a weekend and found it
Monday morning happily idling in wait. I never walk away from a vehicle
unless I secure it and lock it even if I'm letting it warm up. ^_^
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.