Let's Talk Backup Power!

[Eddie_T]

My son has a Generac propane whole house unit and it is 3600 rpm (no inverter).

 

[bud16415]

One other point that the OP made was a system for long term, like end of world stuff. I don't think any of these system will provide power for weeks on end. I think we are talking about systems for multiple days to a week or so. If you want an end of world system I think you are sort of stuck with something that provides renewable power, solar, wind, batteries, all that sort of stuff. Whole different thing. Am I wrong?

Think about even a car engine running 24-7 how long would it take to say accumulate 100,000 miles? say 50MPH 100,000/50=2000hours, 2000hours/24=84days 84days/30=2.8 months call it 3 months. So in one year that would be like running your car for 400,000 miles. Not to mention how many oil changes you would do.



Now think about what engines these little gen units have that are basically law mower engines and you mow your grass say one hour once a week for 25 weeks That’s roughly a year wear per day.



You are not going off the grid with one of these.



As a kid I worked at a golf course and they had two 2 cycle Lawn Boy mowers and as the new kid I ran one of them 8 hours a day 5 days a week mowing around trees and ditches and ponds as did another guy. They bought a new one every year and the new kid got the old one and I got the new one. If you did that for two years they moved you up to greens and tees and other things. I told my dad how crappy these Lawn Boys were that they were shot in two years. He sat me down and we did the math and I realized how good they were compared to our Craftsman.

As a side note they would have me mix gas and oil in one gallon glass wine bottles from the clubhouse and I would tote this glass jug on a rope I put thru the ring over my shoulder all day from patch of trees to patch of trees. I wonder what OSHA would say about that today.

 

[Eddie_T]

A school classmate of mine for 12 years was Garland McGuire son of Cotton Mcguire who had never heard of a grid.

Hooper Bald

 

[Ron Van]

@Ron Van - do you know if the "whole house" stand alone units are inverter type? The ones I'm looking (22K Generac) at come with their own smart switch.

Generac reports True Power™ Technology delivers best-in-class power quality with less than 5 percent total harmonic distortion for clean, smooth operation of sensitive electronics and appliances. However, While there is no firm limit in the US, IEEE 519 recommends that general systems like computers and related equipment have no more than 5% total harmonic voltage distortion with the largest single harmonic being no more than 3% of the fundamental voltage. I would say the Generac is perfectly good for sensitive equipment.

 

[Ron Van]

@Ron Van - do you know if the "whole house" stand alone units are inverter type? The ones I'm looking (22K Generac) at come with their own smart switch.

But no, the Generac 22kw is not an inverter.

 

[Eddie_T]

I have been using a Coleman Powermate during power outages for over 20 years with no damage to TVs, routers, computers or any other electronically controlled equipment. My generator is 3600 rpm with a native sine wave output. I suspect the only generators that present a problem are inverter generators that deliver less than a pure sine wave output. It didn't seem to be an advertising gimmick until after inverter generators became popular.

 

[BuzzLOL]

An extensive wide spread outage would prolly also eventually prevent the natural gas from getting electrically pressurized...

 

[Guzzle]

Since you mention it, I looked thru the Grainger Catalog generator choices some time ago.

The average running watts vs surge watts ratio for these gens was 1:1.2 (20% more) with a max of 1:1.5 (50% more) and yet compressors show a start-up current of 3x (1:3) to 6x (1:6) normal running current values.

So I think the start-up surge is so brief that most generators hardly notice it.
Regardless of whether you're starting up two fridges or one, assuming your total running watts is sized properly.

 

[Eddie_T]

I was procrastinating on whether or not to purchase a 3500W inverter generator. Since that size is 120V only I was considering an autotransformer to provide 240V with a derived neutral. What holds me back is that if the low cost autotransformer proves unreliable I am stuck with both a genny and a transformer. Since my 5000W Coleman still works fine I am now contemplating this approach. I will purchase the autotransformer and wire it such that it will be across the 240V windings of the genny and provide a derived neutral for 120V circuits. If it works through a few outages then I could move forward with the 3500W inverter plan. The autotransformer is less than $100.