Generator for powering home, charging electric vehicles or welder

oil pan 4 · 11-08-16, 02:49 PM

Got a new generator.
It's a generac 17,500w rated 26kw surge.
The engine is a 922cc, 30 hp V-twin with a straight keyed shaft (typically generator engines have tapered shafts that can only be used with a generator).
That means it's more powerful than the vast majority of engine driven welding machines. Or if I don't like using it as a generator I could build it into something else.

I figure I will use this to power my 240v stick welder, plasma cutter, plus air compressor and for power outage backup power now, then in the future I may use it as on road power for an electric vehicle of my own design.

My 7kw troybilt can't power my plasma cutter at full power and can only run my stick welder at about half power.
This 17.5kw machine can power my stick welder at full power or run my plasma cutter at full power and power the air compressor feeding the plasma cutter.
Or should be able to power any single phase electric vehicle charger on the market, maybe 2 of them.
Then still be able to run everything else in the house, aside from the electric clothes dryer.

I will need to ecomod it a little bit. From what I am finding it sucks down between 1 and 1.3 gallons of gas per hour.

Daox · 11-09-16, 03:21 PM

How does one ecomod a generator engine?

oil pan 4 · 11-09-16, 04:22 PM

Same as any carbureted engine.
I was thinking a thermostatic warm air intake, a big cyclone type air cleaner.
A tune up so the engine runs not too rich and maybe just a little lean. I have found running rich can just about cut fuel economy in half and a slightly lean tune can increase fuel economy by 10% and a nearly too lean tune can improve it 20%.
Then on the generator side add some power monitoring gear.
The big one see if I can run it at 50Hz.

First things I need to do is inspect the wiring.
If I want to pull over 50 amps out of this generator it needs to have 6 gauge minimum, looks like it has 6 or 8 gauge. It should have 4 gauge.
Then devise a way to get all 72 amps out of it.
Remove the neutral-ground bond and put it on a switch so I can go between standalone and building tie in mode.

Then maybe add a provision to pump out the fuel so it doesn't get stale.

I'm thinking I might redo the exhaust so it's quieter and blows the nasty carbon monoxide straight up instead of discharging horizontally.

EDIT:
After taking the cover off the main generator wires appear to be 10 gauge. The main obstacle to just replacing the wires is a current sensing transformer just big enough to fit the 10 gauge wires through.
I don't know if the current transformer is part of an over load protection system or line drop compensation voltage booster.
But it's still pretty simple compared to what I'm used to working on.

oil pan 4 · 11-16-16, 01:30 PM

For the engine.

philb · 11-17-16, 11:52 PM

Oil pan 4,
Nice generator! That would run most of my tools and the house at the same time.
Did you get switch gear with it?
What brand are the engine and generator?

I'm a bit confused. 10 awg magnet wire inside the generator will get you about 55 amps per leg with a little cooling that has already been provided. I usually like more cooling than the factory does on mine though.
The transmission lines outside the generator could easily be 6 guage.

I've never tried to eco mod a generator so I'm all ears.

I can't find the table I'm looking for but this one should work. American Wire Gauge table and AWG Electrical Current Load Limits with skin depth frequencies and wire breaking strength

oil pan 4 · 11-18-16, 09:07 AM

The windings in the generator are paralleled 16 or 18 gauge.
I have added a 70 amp panel to the generator for tie in.
The generator and engine both appear to be generac.

nibs · 11-18-16, 10:15 PM

In the early 1980's looked at the possibility of selling house sized gensets running on natural gas, in San Diego, the break even at that time was reasonable. Just got wrapped up in other projects so never took that idea forward.
You might look at propane or nat gas if you already have it. The fuel does not go stale, and it is easy to convert from liquid to gaseous fuel. Not sure if you can get the power output high enough given the lower energy density of propane and gas.

blamberson · 12-19-16, 01:13 PM

Have you considered using hydrogen power for your generator by separating water?

rvCharlie · 12-19-16, 02:00 PM

Quote:

Originally Posted by oil pan 4

Got a new generator.
It's a generac 17,500w rated 26kw surge.
The engine is a 922cc, 30 hp V-twin with a straight keyed shaft (typically generator engines have tapered shafts that can only be used with a generator).
snipped

I will need to ecomod it a little bit. From what I am finding it sucks down between 1 and 1.3 gallons of gas per hour.

If you run it at capacity, it will suck a lot more than that. 17.5kw is ~23.5hp, ignoring conversion losses from engine output to electrical output. Not likely to do better than .5 lbs per hp per hour with a carb'd, fixed timing, air cooled engine, so minimum 1.95 gal/hr with gas at 6 lbs/gal.

Natural gas (previously mentioned) is a good idea; a bit lower output but much cleaner running and longer life. If you're really hard core, conversion to electronic injection/ignition would probably some good from an efficiency standpoint because it could go lean with more advance when running at lower output. Google 'microsquirt'. Only problem is that you'll probably burn more fuel creating the fuel/timing maps than you'll save over the life of the genset.

I've thought for a long time that the most efficient generator for home use would be a bigger version of the little inverter-generators: the generator head feeding DC to a big inverter. The engine could run near idle when demand is low & only ramp up in rpm/power when needed, because the inverter would control AC voltage and frequency.

Charlie

Fionn · 12-20-16, 05:28 AM

What's used in this part of the world is a DC generator feeding a battery bank. The bank feeds the loads via an inverter.
The generator runs intermittently at full load in order to recharge the batteries. The engine speed is varied in order to achieve the desired voltage setpoint on the battery bank.
Idling an engine at low power gives the worst efficiency possible.

11-08-16, 02:49 PM	#1
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	Generator for powering home, charging electric vehicles or welder Got a new generator. It's a generac 17,500w rated 26kw surge. The engine is a 922cc, 30 hp V-twin with a straight keyed shaft (typically generator engines have tapered shafts that can only be used with a generator). That means it's more powerful than the vast majority of engine driven welding machines. Or if I don't like using it as a generator I could build it into something else. I figure I will use this to power my 240v stick welder, plasma cutter, plus air compressor and for power outage backup power now, then in the future I may use it as on road power for an electric vehicle of my own design. My 7kw troybilt can't power my plasma cutter at full power and can only run my stick welder at about half power. This 17.5kw machine can power my stick welder at full power or run my plasma cutter at full power and power the air compressor feeding the plasma cutter. Or should be able to power any single phase electric vehicle charger on the market, maybe 2 of them. Then still be able to run everything else in the house, aside from the electric clothes dryer. I will need to ecomod it a little bit. From what I am finding it sucks down between 1 and 1.3 gallons of gas per hour.

11-09-16, 03:21 PM	#2
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	How does one ecomod a generator engine? __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

11-09-16, 04:22 PM	#3
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	Same as any carbureted engine. I was thinking a thermostatic warm air intake, a big cyclone type air cleaner. A tune up so the engine runs not too rich and maybe just a little lean. I have found running rich can just about cut fuel economy in half and a slightly lean tune can increase fuel economy by 10% and a nearly too lean tune can improve it 20%. Then on the generator side add some power monitoring gear. The big one see if I can run it at 50Hz. First things I need to do is inspect the wiring. If I want to pull over 50 amps out of this generator it needs to have 6 gauge minimum, looks like it has 6 or 8 gauge. It should have 4 gauge. Then devise a way to get all 72 amps out of it. Remove the neutral-ground bond and put it on a switch so I can go between standalone and building tie in mode. Then maybe add a provision to pump out the fuel so it doesn't get stale. I'm thinking I might redo the exhaust so it's quieter and blows the nasty carbon monoxide straight up instead of discharging horizontally. EDIT: After taking the cover off the main generator wires appear to be 10 gauge. The main obstacle to just replacing the wires is a current sensing transformer just big enough to fit the 10 gauge wires through. I don't know if the current transformer is part of an over load protection system or line drop compensation voltage booster. But it's still pretty simple compared to what I'm used to working on. Last edited by oil pan 4; 11-16-16 at 01:25 PM..

11-16-16, 01:30 PM	#4
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	For the engine. Attached Thumbnails

11-17-16, 11:52 PM	#5
philb Apprentice EcoRenovator Join Date: Nov 2010 Location: Oklahoma City Posts: 155 Thanks: 58 Thanked 17 Times in 14 Posts	Oil pan 4, Nice generator! That would run most of my tools and the house at the same time. Did you get switch gear with it? What brand are the engine and generator? I'm a bit confused. 10 awg magnet wire inside the generator will get you about 55 amps per leg with a little cooling that has already been provided. I usually like more cooling than the factory does on mine though. The transmission lines outside the generator could easily be 6 guage. I've never tried to eco mod a generator so I'm all ears. I can't find the table I'm looking for but this one should work. American Wire Gauge table and AWG Electrical Current Load Limits with skin depth frequencies and wire breaking strength

11-18-16, 09:07 AM	#6
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	The windings in the generator are paralleled 16 or 18 gauge. I have added a 70 amp panel to the generator for tie in. The generator and engine both appear to be generac.

11-18-16, 10:15 PM	#7
nibs Apprentice EcoRenovator Join Date: Jun 2010 Posts: 206 Thanks: 1 Thanked 18 Times in 17 Posts	In the early 1980's looked at the possibility of selling house sized gensets running on natural gas, in San Diego, the break even at that time was reasonable. Just got wrapped up in other projects so never took that idea forward. You might look at propane or nat gas if you already have it. The fuel does not go stale, and it is easy to convert from liquid to gaseous fuel. Not sure if you can get the power output high enough given the lower energy density of propane and gas.

12-19-16, 01:13 PM	#8
blamberson Lurking Renovator Join Date: Apr 2010 Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts	Have you considered using hydrogen power for your generator by separating water?

12-20-16, 05:28 AM	#10
Fionn Lurking Renovator Join Date: Aug 2015 Location: Ireland Posts: 25 Thanks: 3 Thanked 6 Times in 2 Posts	What's used in this part of the world is a DC generator feeding a battery bank. The bank feeds the loads via an inverter. The generator runs intermittently at full load in order to recharge the batteries. The engine speed is varied in order to achieve the desired voltage setpoint on the battery bank. Idling an engine at low power gives the worst efficiency possible.