How much power (kw's) do I need for my home?

[90cummins]

I subscribe to various forums and most people think they need 10~20 kw's to operate their home.
While 10+kws' may be necessary if you have an whole house auto back-up generator that must be able to start motors and compressors in refrigerator's, freezers & AC units they consume a huge amount of fuel when being used for prolonged outages even with little or no-load placed on them.
A large 12 or 16kw propane unit may consume 1 or 2 gallons an hour with no load.
For a long term outage you should be thinking about minimizing your consumption and sizing a secondary generator to operate at a minimum of 50~60% of full rated load to handle (absolutely essential loads) for maximum fuel efficiency.
That figure may be small as 2 to 5 kw.
For that I would suggest a Military MEP diesel generator or a Yanmar 3.7 or 5kw unit.
Diesel fuel can be stored safely long term and is easily obtained.
I have the following for my backup plan.
I have an L70 Yanmar driving a 5kw head that provides 3.7kw.
I have performed fuel consumption tests on my generators in order to know how many gallons of fuel I need to have on hand and which one to use depending on my kw needs..
My L70 Yanmar @ 3.54kw load runs 2.4 hrs/gal.
L70 Yanmar @ 1.01kw load runs 4.6 hrs/gal.
I also built a 24v DC generator for my battery backup system using a Yanmar L100 driving a Niehoff N1603 alternator rated 450amps at 28v.
Currently I'm running the engine at 2650rpm and the alternator at 1450rpm, with a 1.01kw AC load I get 5.3 hrs/gal.
This setup working in unison with my batteries will support my home
My informed 2 cents!
90cummins

 

[baja]

getting by with 1000 watt generator

been there done that..with 1k

Here is my info, I live in the baja, because I am beachfront the temperature is 10 degrees cooler everyday than across the street so about 92 all summer. And not real humid because this is a desert where we get rain 3-5 days a year. So during the day I really do not need AC, plus have a above ground pool with a smaller pump. All stoves are propane, all water heaters are propane, this is typical down here but some do have electric appliances but being a hurricane area I put in as much propane as possible. Most people do not own cloths dryers as it is windy here in the winter and summer a daily breeze of 4-6 mph. My kitchens are outdoor also is how temperate the climate is. Winter we do not really ever need heat. I do have one electric oven that obviously would not use during power outage. So I have survived many hurricanes including a cat 3 with a honda eu1000. I have several small AC units what we call mini-splits that are very efficient and low power. I am on city water but because how unreliable their water pump is I also have a 20 cubic meter water tank underground, a 1 meter rooftop tank for gravity feed if all is not working electric and city water pressure and a 1 hp motor for the large tank.

Obviously I can not get the 1 HP motor running on a 1000 honda eu, everything else I can. The major trick I use for water, have the pool, have underground 18 cubic meter, and a rooftop 1 meter gravity feed for power outages. The key here is I also own a travel trailer/boat 12 volt DC pump. I hook up that pump to the underground tank with a 12 volt car/(marine is better) battery and turn off the 1 horsepower 120 volt one. Doing this when I run the generator I charge the 12 vdc battery whenever the generator is on. It is so nice to have water pressure. And I have the back up of the gravity feed if there is an issue.

To date for me the honda EUs have been amazing quality and quiet, got about 1500 hours from a 1000 watt EU. They are just a bit expensive for the small power, but they are gas sippers. First one lasted me about 10 years in this salt air. Bought a 3600 watt propane cheap one from a store in US and it lasted two usages in 2 years and could not run a full sized fridge the second year. Tried a gas no name one and similar. Hence now going to diesel with a quality engine so I have read.. I just purchased three MEP-531 2000 watt diesel generators vintage 2007 with less than 100 hours on them at auction, presuming i will get 2 out of three running.. Again each one is giving me double the power I have been using for 16 years and about 6 hurricanes where I would be without power for up to 3 weeks.

So far I have endured a hit from hurricane John (basically most if not every electric pole went down in my part of the town) and last years Odile just a few went down. Hurricane john was much more powerful here. Being a small town we are low on the priority for getting utilities up and running when there are bigger problems nearby. I generally give away a lot of water. The pool becomes a cooling off feature because the last hurricanes it has been a bit humid after them.

I built my place with the thought of hurricanes, so I use the smallest mini-splits there are for the bedroom where I sleep at night. I wanted comfort at night with the smallest decent generator (I figured there would be fuel shortages, which there are after hurricanes but not as bad as I thought) a EU1000 I have a 7000 btu AC unit. It is driven off 4 amps continuous and ? for start up maybe 12. My honda EU1000 can run it and my bedroom has R9 walls, r30 roof, and double pane vinyl UVA and UVB 99% reflective glass as well as IR reflective glass. Also has a vapor barrier coating. A steel insulted door with weather stripping. So when I wake up with a tiny 5000 or 7000 BTU AC unit my lips are chapped because it is built with insulation.

I am able to stagger the loads starting and set the thermostat on my AC to as low as I can go so it does not cycle at night, and do the same with one fridge set it to coldest once the AC is running. I do this for 12 hours. This has worked for me for 16 years now. But now I would like one more fridge to be running so am moving up to the MEP531s. I am tired of having to consolidate fridges, here I do that because I buy in bulk from COSTCO and that is a 3 hour drive, i try to use that up approaching hurricane season but this year we had two close calls already months away from the peak time. As I mentioned bought three bundled together 2k outputs in a single auction hoping to make 2 run. My property has two sides to it that I can isolate wiring wise, so could run both gennis at the same time for the two independent sides which would be a heck of a lot of power for me vs my old way of honda eu1000.. But will probably just one and have one for backup, alternating their use.

I have 2 old diesel trucks that I keep the fuel tanks full of fuel when a hurricane is approaching and am use to dealing with diesel issues as one is a 1986. So for a low baseline I think I am right there, can be done with a honda 1000eu. Super insulated bedroom, propane appliances for the energy suckers. And a RV 12 volt water pump.

 

[tim292stro]

...I also built a 24v DC generator for my battery backup system using a Yanmar L100 driving a Niehoff N1603 alternator rated 450amps at 28v.
Currently I'm running the engine at 2650rpm and the alternator at 1450rpm, with a 1.01kw AC load I get 5.3 hrs/gal...

I'm very interested in this DC generator you built, I'm building a variable-speed DC generator based on a 20HP water-cooled turbo-diesel and the same C.E. Niehoff N1603 alternator - fueled from a 40-gallon Chevy Suburban tank.

With the engine vs alternator RPMs being different (about 1.83:1 reduction) - are you using a belt, chain, or gears to reduce? Is your engine RPM fixed? Electric or pull-start (or both)? Pictures? Because:

 

[quickfarms]

The reason a lot of people want such huge generators is they do not understand power management. People just add up the breakers or appliances that they want to be able to use and do not understand that most due not run continuously. The second issue is people do not understand balancing loads.

One thing to remember about diesel generators is they do not like to be run without a load or with a light load. Ideally they should be loaded at 66% or above.

I had a friend during a power outage that thought two refrigerators a freezer and a couple of flourescent light bulbs was a maximum load for his 10 KW generator.

 

[tim292stro]

...I had a friend during a power outage that thought two refrigerators a freezer and a couple of flourescent light bulbs was a maximum load for his 10 KW generator...

Ah ha ha , did they run the generator continuously the whole time?

I like the idea of a 2-stage inverter, backed by batteries, backed by a DC generator (PMG if possible). Inverter runs light loads with the smaller stage, takes peak loads with the larger stage. DC generators keeps the batteries charged and helps with sustained large loads.

 

[cpf240]

Couldn't one use their monthly power bill as a baseline for your "typical" usage?

 

[Crabbie]

Excellent post. Energy conservation is the key whether living off grid or on grid during a power outage. We live a modern lifestyle with a 600 watt hydroelectric turbine and a 5KW MEP 002a back up. We have a gas stove, dryer and water heater, leave the lights on when we want (albeit they are compact fluorescent) and the satellite internet never is off and the GE commercial electric frig and freezer of course are always on.

Last time we ran the generator was when lightening hit the turbine (still can't figure out how it got through the redundant breakers and surge protectors??) and I had to wait 10 days for a new voltage regulator for the turbine.

 

[dependable]

If you are talking MEP's ''real KWs'', not max output claims on 3600 RPM box store stuff, 5 KW runs my house. (have test run house as load with both 002 and 802.) That includes the 240V well pump, oil burner, dishwasher, laundry, fridge , freezer, couple window ACs, etc. Some load management required, mostly common sense; don't run it all at the same time. Have gas cook stove and cloths dryer.

If you have electric stove, water heater, or similar, or need more AC, 10KW would be good.

If you have need for a lot of AC or have electric heat, you may need some more.

 

[m109a2]

Last big outage we had was hurricane Rita and we were down a month.Man did I learn a lot,I bought a hop sing 5500 watt peak witch is about 3500 watts died shortly after the power came back on.I managed just fine,Buy a small window unit,watch all power consumption.I will not go threw that again,I now have a MEP,1971 m35a2cw/w and a 109 box on a deuce frame.I `m not saying bring on the storm but I will not be caught with my pants down again ever!Al

 

[Isaac-1]

m109a2, you were also one of the lucky ones, my inlaws lived just east of Lake Charles when Rita hit, they lost part of the roof off their house (blue tarp for 4 months), were running low on Propane before the storm hit and ran out 2 days after it hit (had ordered a refill 2 weeks before, but everyone was topping off as Katrina hit New Orleans just 3 weeks before Rita, so being a residential customer they did not get the refill until 3 weeks after the storm) the same day the power came back on. My father who lived about 30 miles north of Lake Charles on a main power line on Hwy 171 was without for over 5 weeks (substation the lines fed was destroyed so the power company turned off the lines until it was rebuilt, and did not care about the handful of customers that were directly connected to it), by contrast I was lucky living in DeRidder our power came back on 5 days after Rita hit, but there were people within walking distance of my house that were out for over 2 weeks.

 

[m109a2]

Hey Isaac-1 since you live in Deridder you must know the jeepsinker, he has a spread in Drycreek.Super nice fellow and a wealth of info.Al

 

[Isaac-1]

We have exchanged a few messages online over the years, but as far as I know we have not met in person

 

[90cummins]

Here are the photos of my 24v backup generator.
It has a 24v starter that operates off my battery pack which eliminates a separate battery.
It has a key switch for starting and a toggle switch for energizing the generator field and for safety a Blue Seas Dc disconnect switch.
There is a recoil and the engine starts easily but the inertia of the engine & generator makes for a healthy pull.
It has a fixed speed generator governor that I modified to allow large rpm adjustments and is easily adjusted.
The engine has a tapered generator crankshaft but there was a large area before the crank was tapered so I used a bushed bore pulley with no key to mount the drive pulley.
I bought several different pulleys so I could adjust the engine/generator drive speed.
As it sets it runs 5.3 hrs/gal with a steady 1kw load. At this lowered power level the batteries assist it to handle large surges when my deep well pump starts.
In the future I will experiment with injection timing to reduce fuel consumption.
By changing the engine speed I can easily get 5kws DC which is a 4kw AC load.
This generators sweet spot for efficiency is approximately 2000 rpm but is currently turning 1400+-.
Prior to buying it I contacted Niehoff and the engineer I talked to sent me the drawings and the testing overhaul manual with graphs showing all performance curves.
The unit next to it is an MEP-952-b APU rated 5.5kw. It was reset and had 3.3 hours on the clock.
I found this unit after I built mine and bought it because it was everything I wanted including low oil pressure and high temperature shut down's.
I has no batteries or fuel tank. It does have an electric fuel pump and 20' hose for drawing fuel from a remote source such as a 55 gallon tank.
Power connection is with a NATO slave that has an Anderson 175a connector on the other end.
I'm currently working on the governor to lower the engine speed from 3000 to less than 2000 rpm to decrease fuel consumption.
The pallet is my template for a power house which will shelter them outside.
It will be insulated for heat retention and noise reduction and have automatic cooling fans.
Don't know how to turn the photos; sorry.
That gentlemen is all for now!












More later;
90cummins

 

[tim292stro]

Ooo! Could you post those 1603 spec files? The C.E. Neihoff product webpage is sterile at best for specification documents. I'm interested especially in the curves - I was planning on tuning my DC generator software using a load bank, but if I could get access to the curves that would at least get me close for bring-up. You can attach PDF files directly to SS pages.

One thing you might consider for a "kick-up" is to use a shunt and a comparator op-amp+MOSFET to trigger a solenoid. This way as the current increases across the shunt, the voltage increases as well, which the comparator would see. Once the shunt input exceeds the kick-up set voltage (via a potentiometer), the output energizes the MOSFET, and powers the solenoid kicking the throttle up.

For my setup, I plan on replacing the N3211 voltage regulator with a custom one I'm building that also controls the engine operation and speed (via a stepper motor for the throttle). This will also allow me to schedule run-times and "black-out" times for politeness in campgrounds - and will allow me to support a NATO charge plug from the tow vehicle to also charge the batteries without confusing the voltage regulator.

Here, rotated for you

 

[rustystud]

Ooo! Could you post those 1603 spec files? The C.E. Neihoff product webpage is sterile at best for specification documents. I'm interested especially in the curves - I was planning on tuning my DC generator software using a load bank, but if I could get access to the curves that would at least get me close for bring-up. You can attach PDF files directly to SS pages.

One thing you might consider for a "kick-up" is to use a shunt and a comparator op-amp+MOSFET to trigger a solenoid. This way as the current increases across the shunt, the voltage increases as well, which the comparator would see. Once the shunt input exceeds the kick-up set voltage (via a potentiometer), the output energizes the MOSFET, and powers the solenoid kicking the throttle up.

For my setup, I plan on replacing the N3211 voltage regulator with a custom one I'm building that also controls the engine operation and speed (via a stepper motor for the throttle). This will also allow me to schedule run-times and "black-out" times for politeness in campgrounds - and will allow me to support a NATO charge plug from the tow vehicle to also charge the batteries without confusing the voltage regulator.

Here, rotated for you

View attachment 570049View attachment 570050

Alright Tim, what nefarious plan are you up too now ? First it was the tents, now it's generators. Your not planning on starting a "Military Vehicle" cult are you ? If so, count me in !!!

 

[tim292stro]

The generator is for the trailer that carries the tents in FOBIC, it was always part of the scope:

"...

• Trailer with generator for transportation
  • 40-gallons diesel tank
  • 24VDC generator, auto-start

..."

So many pieces need to be assembled in order to get it to run right. After all those ToughBooks, lights, and projectors need to be charged and powered...

As for any cults, my wife says: "Hail Hydra!" may be as close as I get.

 

[rustystud]

The generator is for the trailer that carries the tents in FOBIC, it was always part of the scope:

"...

• Trailer with generator for transportation
  • 40-gallons diesel tank
  • 24VDC generator, auto-start

..."

So many pieces need to be assembled in order to get it to run right. After all those ToughBooks, lights, and projectors need to be charged and powered...

As for any cults, my wife says: "Hail Hydra!" may be as close as I get.

Good, another "Avengers" fan !

 

[90cummins]

Niehoff 1603 Performance Data.

As requested here is the Niehoff performance data along with drawings for fabrication purposes. Hope you find it as useful as I did.
90cummins
View attachment N1603 Characteristics.pdfView attachment n1603.pdfView attachment N3211.pdf

 

[tim292stro]

Beautiful!!

Awesome, thanks so much - I've had less luck with the C.E. Niehoff people, no returned emails, no returned phone calls. I was pretty close to sending them a regular old letter...

 

[90cummins]

I'm interested in the control circuit you described.
Will it be a linear increase based on amps/volts or an idle full throttle setup?
On my DC sets including the MEP-952b it should decrease the fuel consumption by 50% or better.
90cummins

Ooo! Could you post those 1603 spec files? The C.E. Neihoff product webpage is sterile at best for specification documents. I'm interested especially in the curves - I was planning on tuning my DC generator software using a load bank, but if I could get access to the curves that would at least get me close for bring-up. You can attach PDF files directly to SS pages.

One thing you might consider for a "kick-up" is to use a shunt and a comparator op-amp+MOSFET to trigger a solenoid. This way as the current increases across the shunt, the voltage increases as well, which the comparator would see. Once the shunt input exceeds the kick-up set voltage (via a potentiometer), the output energizes the MOSFET, and powers the solenoid kicking the throttle up.

For my setup, I plan on replacing the N3211 voltage regulator with a custom one I'm building that also controls the engine operation and speed (via a stepper motor for the throttle). This will also allow me to schedule run-times and "black-out" times for politeness in campgrounds - and will allow me to support a NATO charge plug from the tow vehicle to also charge the batteries without confusing the voltage regulator.

Here, rotated for you

View attachment 570049View attachment 570050