LOL, don't tell anyone, but I've got 7 generators!! Good review on generator sizing. That's good advice to get a generator 50% larger than your normal load. Makes the genny work but not work too hard. I run my outside workshop off of a generator... no grid power out there, and way too expensive to get power run to it. I run it with 2 generators... if I only need lights and a fan running, I've got a Sportsman 1000 inverter genny. If I'm using power tools (usually is what happens!) I've got a Black Diamond (made by Champion) 3500/4350. Getting close to 300 hours on it now. It's been a good unit so far, runs everything in my shop, even my little wire feed welder, although that is all the genny wants, and sometimes more than it wants if you are welding heaver steel with the settings turned up. My backup generator for the house is a Coleman powermate 6800/8750 powered by a Yamaha MZ360 engine. Great machine too... it will run the entire house, haven't tried to run the central air with it, but it does run the gas furnace. Running the gas out of the carb is good, but it's even better to drain the carb bowl by opening the drain screw that is on most carburetors. Even if you close the fuel shutoff valve and let it run until it dies, there is still a small amount of fuel still in the float bowl. Best to drain it ALL out, that keeps the stupid ethanol in the fuel from absorbing moisture from the air and gunking things up. I wish they would outlaw this stupid ethanol in the fuel... I know, it will never happen.
I have been plagued by old gas problems that rust and gum up fuel tanks and carbs. I used to drain the fuel tank and carburetor but, still had problems; carburetor passageways would corrode, clogging up jets, and in some cases, totally ruining the carburetor. I since have solved this by using alcohol free gas and adding Sta-Bil and 1 oz of Marvel Mystery Oil per gallon. I have tested it out to 5 years so far and surprisingly, it has worked! No corrosion, gum, rust, staining or sediment problems, the gas even still smells fresh after 5 years.
@HollisDoesStuff Good deal. Consider yourself lucky! In my area we haven't had ethanol free gasoline available for probably 5 years or more now. I have to treat all of my small engine gas, and be almost religious about running carbs dry and draining the float bowls. If I forget one, the carb almost always to come off and go in the ultrasonic cleaner. I really hate the ethanol gas! I've been using Stabil Marine 360 at double the label rate plus 1 Oz per gallon of SeaFoam or the store brand equivalent. So far it seems to work... between treating the gas and religiously running dry and draining float bowls, I've only had to use my ultrasonic cleaner on other people's stuff for the past few years.
That's a good point about using the smallest generator to run your appliances during a long term power outage. Your basic, lowest cost portable generator runs at a constant 3,600 rpm to maintain the 60 Hertz line frequency. Since the engine is running at its maximum rated speed, you end up consuming a lot of fuel even with no load. So, that smaller 1,200 watt generator comes in quite handy at times. It is relatively light weight, less noisy that higher wattage models and, best of all - sips fuel. Just make sure you are not over loading it. The most deceptive load in the house is the kitchen refrigerator, it has a huge starting surge current. The surge current is generally 10 to 20 times the run current. To be safe, you need 2,500 watts for up to 5 seconds to cleanly start a standard US kitchen refrigerator. Also, if you apply power to your frig within 20 minute after it lost power, some frig models go into defrost mode for 5 to 20 minutes. During defrost, a 600 to 720 watt heater is turned on in the freezer to melt ice off the cooling coils. When the frig comes out of defrost mode, the refrigeration spends the next 15 to 60 minutes removing the heat from the defrost process.
It really depends on your fridge. Mine is a newer 15 cu ft Samsung, I think it's an "inverter" (whatever that means). The biggest draw was 236 watts on startup, and when running takes 50 to 100 watts. The freezer is a newer stand up type, takes 600 to start and around 100 steady when running, but only runs about 1/3 of the time. I'd like to see what an older fridge would measure, might have one at work to test. Video idea maybe 🤔
@@HollisDoesStuff Sounds good. In about the early 1990's, I think there was a government mandate to reduce the power consumption of refrigerators. Before that, the typical US kitchen frig pulled 600 watts when running. The improved refrigerators now pull about 120 watts when running. They still use an induction motor, just more efficient. The Inverter type refrigerators use a DC compressor motor, controlled by a switching power supply. I don't know the exact Inverter designs they are using now. If they wanted to obtain the highest efficiency possible, they would also use DC fan motors, a variable expansion valve, and reverse refrigeration cycle to heat the evaporator (the radiator that does the cooling) for defrost. With the Inverter type frig, they could also incorporate a slow ramp up by the compressor to substantially reduce surge currents. Speaking of "Surge Current", you can't measure it using just any meter, it has to be specially designed to capture that fractional second event. I use the UNI-T UT216C clamp meter (in the Inrush current mode), which I have verified the accuracy of using an oscilloscope.
Your better off going hybrid in most cases if your power is knocked out for lengths of time - In that case the battery's handle the intermediate and peak loads - I only average 24 KWs a day so when the power is knocked out for a month - I just let the generator deliver a constant 1100 to the battery's - Then the house runs off the inverter that's connected to some batterys - I'm fortunate and have a heavy stationary engine generator so it only uses 1..5 gallons of fuel a day - I have a 8 kw stand by generator but it uses 25 gallons of propane a day - yet my average load is only 1 kw an hour - Two inverters on a set of battery's gives all the power I need and some extra -
@@able880 I have basically the same setup. I live in Florida, they don't allow full off-grid so, I use the solar to supplement the grid power. If power is out long term, I use a 2kW inverter generator to recharge the battery bank. I also built an EMP proof generator, composed of a 10 hp single cylinder diesel running at 1,800 rpm turning a basic brushless generator head where the field is energized by a large AC capacitor. There are no electronics in either the engine or generator.
Many viewers probably know this but your appliances will usually list either their power usage in wattage or amps. If it lists Wattage, then great, that makes it easy. If it lists something like 'peak Amps' or similar, then multiply the Amperage x the Voltage (in the US, typically 120 Volts or so), and that will give you the Wattage. Search the web of Ohm's Law calculator if you want to use one. For example, a device says peak Amps are "2 Amps" and it runs on a 120 Volt circuit. 120 Volts x 2 Amps = 240 Watts. Anyway, add up the Wattage of the stuff you want to run on the generator to have an idea of what you will need. Other commenters might have already mentioned this, but many appliances have a higher start-up power need compared to when it's already running. A fridge compressor, an HVAC compressor, etc. And devices that heat up, such as clothing irons, hair driers, coffee makers, electric tea kettles, etc. typically have a relatively high Wattage. Refer to your user manual or appliance websites for this info if necessary, to make sure you account for it when shopping for your generator.
I'm buying the power meter you mentioned. Then I'm figuring out if the generator I currently have is big enough. New subscriber. Great video! Only thing I would have added is ethanol free fuel at least while sitting for long periods. Run the "cheaper" stuff during power runs. I run ethanol free in my chainsaws because of the longer storage life.
Here in onterable we dont have ethenal free fuel anymore unless you can find a marina that will fill cans vut most dont. I just try to use some fuel from the 3 generators i got and add new to them every couple months. Real pain in the but.
I just learned a Kill-a-watt meter takes batteries. I threw one away that was only a few years old and only ever used sparatically. Oh well. I bought a new one and paid the idiot tax.lol
I have two of the Kill-A-Watt P3 models, they don't use batteries. They use a 0.47 uF capacitor as a series resistor to drop the 120 Vac down to a lower voltage where it is rectified to run the electronics in the unit. The 0.47 uF capacitor does lose capacitance over time so, will need to be replaced at some point. These meters are super handy for measuring the power consumption of various appliances to figure out what your generator can power.
I have two trifuel generators: a yamaha 2400 running watts 120v and a generac 4000 running watts 240v. I can charge my battery system with either one or both simultaneous in 2 hours. Next year I am currently starting to work intalling a 6500 rated watt system which should mostly cover my needs with either grid or generator backup
I live in the rural deep south - power outages are common - Up till about 1960s before REA sent power out here, those who had power had 32 volts farm light plants - You can look up 32 volts farm light plants on the net - Farm homes had 16 two volt batteries there home ran off - a charged battery bank lasted for 6 days - then every Friday the battery's were charged all day. - 32 volt farm homes had all the appliances city homes had but all the appliances were 32 volts DC - The charging generators burned around 5 gallons of fuel - the batteries lead acid batterys lasted 40 to 70 yrs -
That's really cool. I live on the old family homestead, I'm told that they didn't get grid power until the 1950s. Before then they had a 32v system too, run from a water wheel. There used to be a sawmill here that originally ran from water power, then diesel, then electric once they had grid power.
@able880 Thanks for that farm history before power was run out to the farms. I didn't realize they were using a 32 volt DC standard. I have been restoring antique radios for the past 50 years and very familiar with farm radios, which were always battery powered. Some just used a set of radio dry cell batteries. The better radios ran completely off of 6 volts DC. I have never come across one that ran off of 32 Volta DC - very interesting!
@@billharris6886the 6 volt and 32 volt radios were very common in rural homes - Homes with 6 volts power were said to have a junior light plant - Most of those homes had a huge 1000 amp 6 volt farm battery and a 150 watt 6 volt generator for lights fans and radios - I remember seeing those farm light battery's at Sears catalog store up till I guess 1965 or so -
@@billharris6886my family was also heavenly invested in the radio communications business - I can remember people bring farm radios to my grandfather and uncle's shop to be worked on as a kid - There were short wave versions of those radios - I think those might have used 13 tubes for the SW frequency's - During WW2 people sat up all night listening to live SW broadcast from the different fronts in Europe and the Pacific - they had son's in those different fronts and could hear what was happening in real time during WW2 in the battle fields - I grew up hearing SW and also have listened to it all my life -
@@billharris6886the homes with 6 volts used kerosene absorption fridges and freezers - Also on Saturdays some bought there radio battery to battery shops to be charged as they shopped - Also I remember the vibrators in the radios went bad often -
I got 3 generators. A little champion 2000 watt surge inverter style which does most what i need in a short outage. Then 2 bigger ones. 6500 and a 7500 continuous. I like to keep them loaded to about 50 percent load which is most efficiant. I also let the neighbours next to me pkug a cord in too so im using both legs and they also help with fuel cost too.
Good, informative video! One request though, please work on the sound. I had to turn up the sound nearly all the way, then when you turned (closer to the microphone?) it was too loud.
Your base load needs are fairly easy to calculate. Determine which appliances are needed, then add up the wattage requirements. Surge demands should be included, for refrigeration, sump pump, and furnace blower. Stand-by generators are best when they are “right-sized”. Portable generators must be plugged in to an appliance(s), or back-feed into a service panel. Main power disconnect must be open, or in the off position, when back-feeding a panel. Fuel choice is most important, because of availability, during extended period of operation.
Excellent comments! I should have gone into furnace blowers, however they're typically hard wired and unless you have a transfer switch, not the easiest to run on a portable generator.
My grandfather was a first generation generator mechanic - I'm a third generation SCR generator mechanic - I spent my yrs working on generators in the offshore oilfields - every thing was off grid offshore - This is a general basic rule for 3600 rpm generators running at 25% load - This is for single cylinder engines with over head valves - If your running on propane it. Will burn 1 gallon of propane per 2000 watts of power drawn off it - If your burning gasoline it will burn 1 gallon of gasoline per 3000 watts of power used - The fuel air mix is most efficient at a 25 % load on most 3600 rpm single cylinder air cooled engines - That's 25% of it's rated load - Most 4000 watt generators have a 7 HP engine - 1 HP generates 416 watts so 7 HP × 416 watts = 2912 watts - In that case the best fuel economy would be at 25% of 2912 watts that's 728 watts - The remaining unused 2184 watts would be available for surges as when a fridge motor starts. - When the run time of a generator is stated at 50% load - in this cast that is 25% of the continues full out put of the generator - Light weight 1000 watt inverter generator at 50 % load run at 2700 RPMs - Running on the economy setting at the lower 2700 RPM they might only burn 1 gallon of gas per 7000 watts of power generated - Light weight high speed generators are awesome - but the down side is they ware out in 1 to 2000 hours of run time - There are stationary single cylinder engine generators built in the 1930s - many of them only run at 450 RPMs - one gallon of fuel can generate 20000 watts of power - there often used to generate voltage on pipeline - the down side is a 2900 watt stationary engine generator can weigh 5 tons - They just change the piston rings and connecting rod bearing every 12 yrs or every 105000 hrs of run time - at slow speeds there fuel efficient and and the rings don't ware out fast as they do with high speed engines -
@able880 You are correct about portable generators; priority one is low cost. Efficiency, noise, vibration, and engine life are low priorities in the design. Flinging all that mass around at 3,600 rpm, simultaneously scrubbing the cylinder walls, and using a cheap 2-pole generator head with insufficient iron core can't Possibly have good efficiency. Engine speed is very important in regards to wear, noise, vibration, and efficiency. Low speed diesels are the best choice where longevity and efficiency are concerned, if you can tolerate huge size and weight.
LOL, don't tell anyone, but I've got 7 generators!! Good review on generator sizing. That's good advice to get a generator 50% larger than your normal load. Makes the genny work but not work too hard.
I run my outside workshop off of a generator... no grid power out there, and way too expensive to get power run to it. I run it with 2 generators... if I only need lights and a fan running, I've got a Sportsman 1000 inverter genny. If I'm using power tools (usually is what happens!) I've got a Black Diamond (made by Champion) 3500/4350. Getting close to 300 hours on it now. It's been a good unit so far, runs everything in my shop, even my little wire feed welder, although that is all the genny wants, and sometimes more than it wants if you are welding heaver steel with the settings turned up.
My backup generator for the house is a Coleman powermate 6800/8750 powered by a Yamaha MZ360 engine. Great machine too... it will run the entire house, haven't tried to run the central air with it, but it does run the gas furnace.
Running the gas out of the carb is good, but it's even better to drain the carb bowl by opening the drain screw that is on most carburetors. Even if you close the fuel shutoff valve and let it run until it dies, there is still a small amount of fuel still in the float bowl. Best to drain it ALL out, that keeps the stupid ethanol in the fuel from absorbing moisture from the air and gunking things up. I wish they would outlaw this stupid ethanol in the fuel... I know, it will never happen.
Good point about draining the bowl. Up here, our "Supreme" gas is ethanol free, it's all I run in anything but the truck.
I have been plagued by old gas problems that rust and gum up fuel tanks and carbs. I used to drain the fuel tank and carburetor but, still had problems; carburetor passageways would corrode, clogging up jets, and in some cases, totally ruining the carburetor. I since have solved this by using alcohol free gas and adding Sta-Bil and 1 oz of Marvel Mystery Oil per gallon. I have tested it out to 5 years so far and surprisingly, it has worked! No corrosion, gum, rust, staining or sediment problems, the gas even still smells fresh after 5 years.
@HollisDoesStuff Good deal. Consider yourself lucky! In my area we haven't had ethanol free gasoline available for probably 5 years or more now. I have to treat all of my small engine gas, and be almost religious about running carbs dry and draining the float bowls. If I forget one, the carb almost always to come off and go in the ultrasonic cleaner. I really hate the ethanol gas! I've been using Stabil Marine 360 at double the label rate plus 1 Oz per gallon of SeaFoam or the store brand equivalent. So far it seems to work... between treating the gas and religiously running dry and draining float bowls, I've only had to use my ultrasonic cleaner on other people's stuff for the past few years.
The camera and the microphone in "the big TV" are always on, along with the adapter.
That's a good point about using the smallest generator to run your appliances during a long term power outage. Your basic, lowest cost portable generator runs at a constant 3,600 rpm to maintain the 60 Hertz line frequency. Since the engine is running at its maximum rated speed, you end up consuming a lot of fuel even with no load. So, that smaller 1,200 watt generator comes in quite handy at times. It is relatively light weight, less noisy that higher wattage models and, best of all - sips fuel. Just make sure you are not over loading it.
The most deceptive load in the house is the kitchen refrigerator, it has a huge starting surge current. The surge current is generally 10 to 20 times the run current. To be safe, you need 2,500 watts for up to 5 seconds to cleanly start a standard US kitchen refrigerator. Also, if you apply power to your frig within 20 minute after it lost power, some frig models go into defrost mode for 5 to 20 minutes. During defrost, a 600 to 720 watt heater is turned on in the freezer to melt ice off the cooling coils. When the frig comes out of defrost mode, the refrigeration spends the next 15 to 60 minutes removing the heat from the defrost process.
It really depends on your fridge. Mine is a newer 15 cu ft Samsung, I think it's an "inverter" (whatever that means). The biggest draw was 236 watts on startup, and when running takes 50 to 100 watts. The freezer is a newer stand up type, takes 600 to start and around 100 steady when running, but only runs about 1/3 of the time. I'd like to see what an older fridge would measure, might have one at work to test. Video idea maybe 🤔
@@HollisDoesStuff Sounds good. In about the early 1990's, I think there was a government mandate to reduce the power consumption of refrigerators. Before that, the typical US kitchen frig pulled 600 watts when running. The improved refrigerators now pull about 120 watts when running. They still use an induction motor, just more efficient. The Inverter type refrigerators use a DC compressor motor, controlled by a switching power supply. I don't know the exact Inverter designs they are using now. If they wanted to obtain the highest efficiency possible, they would also use DC fan motors, a variable expansion valve, and reverse refrigeration cycle to heat the evaporator (the radiator that does the cooling) for defrost. With the Inverter type frig, they could also incorporate a slow ramp up by the compressor to substantially reduce surge currents.
Speaking of "Surge Current", you can't measure it using just any meter, it has to be specially designed to capture that fractional second event. I use the UNI-T UT216C clamp meter (in the Inrush current mode), which I have verified the accuracy of using an oscilloscope.
Your better off going hybrid in most cases if your power is knocked out for lengths of time -
In that case the battery's handle the intermediate and peak loads -
I only average 24 KWs a day so when the power is knocked out for a month - I just let the generator deliver a constant 1100 to the battery's -
Then the house runs off the inverter that's connected to some batterys -
I'm fortunate and have a heavy stationary engine generator so it only uses 1..5 gallons of fuel a day -
I have a 8 kw stand by generator but it uses 25 gallons of propane a day - yet my average load is only 1 kw an hour -
Two inverters on a set of battery's gives all the power I need and some extra -
@@able880 I have basically the same setup. I live in Florida, they don't allow full off-grid so, I use the solar to supplement the grid power. If power is out long term, I use a 2kW inverter generator to recharge the battery bank. I also built an EMP proof generator, composed of a 10 hp single cylinder diesel running at 1,800 rpm turning a basic brushless generator head where the field is energized by a large AC capacitor. There are no electronics in either the engine or generator.
Many viewers probably know this but your appliances will usually list either their power usage in wattage or amps. If it lists Wattage, then great, that makes it easy. If it lists something like 'peak Amps' or similar, then multiply the Amperage x the Voltage (in the US, typically 120 Volts or so), and that will give you the Wattage. Search the web of Ohm's Law calculator if you want to use one. For example, a device says peak Amps are "2 Amps" and it runs on a 120 Volt circuit. 120 Volts x 2 Amps = 240 Watts. Anyway, add up the Wattage of the stuff you want to run on the generator to have an idea of what you will need. Other commenters might have already mentioned this, but many appliances have a higher start-up power need compared to when it's already running. A fridge compressor, an HVAC compressor, etc. And devices that heat up, such as clothing irons, hair driers, coffee makers, electric tea kettles, etc. typically have a relatively high Wattage. Refer to your user manual or appliance websites for this info if necessary, to make sure you account for it when shopping for your generator.
Great info. I feel like the listed specs are not always accurate though, usually a worse case scenario. Measuring gets you the real world specs.
I'm buying the power meter you mentioned. Then I'm figuring out if the generator I currently have is big enough.
New subscriber. Great video!
Only thing I would have added is ethanol free fuel at least while sitting for long periods. Run the "cheaper" stuff during power runs.
I run ethanol free in my chainsaws because of the longer storage life.
Absolutely. Our "Supreme" in New Brunswick is ethanol free and all I run in small engines.
Here in onterable we dont have ethenal free fuel anymore unless you can find a marina that will fill cans vut most dont.
I just try to use some fuel from the 3 generators i got and add new to them every couple months. Real pain in the but.
You present incredibly well to be able to fit so much inside of one single edit. Looking forward to learning more about your off-grid experiences! 👍
Thank you so much! More to come...
I just learned a Kill-a-watt meter takes batteries. I threw one away that was only a few years old and only ever used sparatically. Oh well. I bought a new one and paid the idiot tax.lol
Luckily they're relatively inexpensive lol.
My Kill-a-Watt doesn't take batteries... it's one of the original models.
I have two of the Kill-A-Watt P3 models, they don't use batteries. They use a 0.47 uF capacitor as a series resistor to drop the 120 Vac down to a lower voltage where it is rectified to run the electronics in the unit. The 0.47 uF capacitor does lose capacitance over time so, will need to be replaced at some point. These meters are super handy for measuring the power consumption of various appliances to figure out what your generator can power.
I have multiple generators. I use them to back up my solar/battery power off grid situation.
That's where I'm heading.
I have several generators as well in various sizes. For long term power outages, this is a must in case a generator fails.
I have two trifuel generators: a yamaha 2400 running watts 120v and a generac 4000 running watts 240v. I can charge my battery system with either one or both simultaneous in 2 hours. Next year I am currently starting to work intalling a 6500 rated watt system which should mostly cover my needs with either grid or generator backup
@@kevinm234That's a good start. I have a 4,000 watt off-grid system I use to run the house with when full sun is available.
I live in the rural deep south - power outages are common -
Up till about 1960s before REA sent power out here, those who had power had 32 volts farm light plants -
You can look up 32 volts farm light plants on the net -
Farm homes had 16 two volt batteries there home ran off - a charged battery bank lasted for 6 days - then every Friday the battery's were charged all day. -
32 volt farm homes had all the appliances city homes had but all the appliances were 32 volts DC -
The charging generators burned around 5 gallons of fuel - the batteries lead acid batterys lasted 40 to 70 yrs -
That's really cool. I live on the old family homestead, I'm told that they didn't get grid power until the 1950s. Before then they had a 32v system too, run from a water wheel. There used to be a sawmill here that originally ran from water power, then diesel, then electric once they had grid power.
@able880 Thanks for that farm history before power was run out to the farms. I didn't realize they were using a 32 volt DC standard. I have been restoring antique radios for the past 50 years and very familiar with farm radios, which were always battery powered. Some just used a set of radio dry cell batteries. The better radios ran completely off of 6 volts DC. I have never come across one that ran off of 32 Volta DC - very interesting!
@@billharris6886the 6 volt and 32 volt radios were very common in rural homes -
Homes with 6 volts power were said to have a junior light plant -
Most of those homes had a huge 1000 amp 6 volt farm battery and a 150 watt 6 volt generator for lights fans and radios -
I remember seeing those farm light battery's at Sears catalog store up till I guess 1965 or so -
@@billharris6886my family was also heavenly invested in the radio communications business -
I can remember people bring farm radios to my grandfather and uncle's shop to be worked on as a kid -
There were short wave versions of those radios - I think those might have used 13 tubes for the SW frequency's -
During WW2 people sat up all night listening to live SW broadcast from the different fronts in Europe and the Pacific - they had son's in those different fronts and could hear what was happening in real time during WW2 in the battle fields -
I grew up hearing SW and also have listened to it all my life -
@@billharris6886the homes with 6 volts used kerosene absorption fridges and freezers -
Also on Saturdays some bought there radio battery to battery shops to be charged as they shopped -
Also I remember the vibrators in the radios went bad often -
I got 3 generators. A little champion 2000 watt surge inverter style which does most what i need in a short outage.
Then 2 bigger ones. 6500 and a 7500 continuous. I like to keep them loaded to about 50 percent load which is most efficiant. I also let the neighbours next to me pkug a cord in too so im using both legs and they also help with fuel cost too.
Sounds like you know what you're doing, and good idea about helping a neighbour!
Good, informative video! One request though, please work on the sound. I had to turn up the sound nearly all the way, then when you turned (closer to the microphone?) it was too loud.
Thanks for the feedback, I'll definitely look into it. Still learning!
Your base load needs are fairly easy to calculate. Determine which appliances are needed, then add up the wattage requirements. Surge demands should be included, for refrigeration, sump pump, and furnace blower. Stand-by generators are best when they are “right-sized”. Portable generators must be plugged in to an appliance(s), or back-feed into a service panel. Main power disconnect must be open, or in the off position, when back-feeding a panel. Fuel choice is most important, because of availability, during extended period of operation.
Excellent comments! I should have gone into furnace blowers, however they're typically hard wired and unless you have a transfer switch, not the easiest to run on a portable generator.
My grandfather was a first generation generator mechanic - I'm a third generation SCR generator mechanic -
I spent my yrs working on generators in the offshore oilfields - every thing was off grid offshore -
This is a general basic rule for 3600 rpm generators running at 25% load -
This is for single cylinder engines with over head valves -
If your running on propane it. Will burn 1 gallon of propane per 2000 watts of power drawn off it -
If your burning gasoline it will burn 1 gallon of gasoline per 3000 watts of power used -
The fuel air mix is most efficient at a 25 % load on most 3600 rpm single cylinder air cooled engines -
That's 25% of it's rated load -
Most 4000 watt generators have a 7 HP engine -
1 HP generates 416 watts so 7 HP × 416 watts = 2912 watts -
In that case the best fuel economy would be at 25% of 2912 watts that's 728 watts -
The remaining unused 2184 watts would be available for surges as when a fridge motor starts. -
When the run time of a generator is stated at 50% load - in this cast that is 25% of the continues full out put of the generator -
Light weight 1000 watt inverter generator at 50 % load run at 2700 RPMs -
Running on the economy setting at the lower 2700 RPM they might only burn 1 gallon of gas per 7000 watts of power generated -
Light weight high speed generators are awesome - but the down side is they ware out in 1 to 2000 hours of run time -
There are stationary single cylinder engine generators built in the 1930s - many of them only run at 450 RPMs - one gallon of fuel can generate 20000 watts of power - there often used to generate voltage on pipeline - the down side is a 2900 watt stationary engine generator can weigh 5 tons -
They just change the piston rings and connecting rod bearing every 12 yrs or every 105000 hrs of run time - at slow speeds there fuel efficient and and the rings don't ware out fast as they do with high speed engines -
@able880 Thanks, great information!
@able880 You are correct about portable generators; priority one is low cost. Efficiency, noise, vibration, and engine life are low priorities in the design. Flinging all that mass around at 3,600 rpm, simultaneously scrubbing the cylinder walls, and using a cheap 2-pole generator head with insufficient iron core can't
Possibly have good efficiency. Engine speed is very important in regards to wear, noise, vibration, and efficiency. Low speed diesels are the best choice where longevity and efficiency are concerned, if you can tolerate huge size and weight.
Wow, great info! Thanks!