Backup power for your computer

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I work from home every day for my job, so I have to have reliable electricity. Unfortunately, on occasion we have power outages where I live. Most of these last less than a minute, so my UPS handles them without a problem. But sometimes they can last for a few hours.

I tried using a 400W voltage inverter connected to my car; I plugged the UPS into the voltage inverter, and I plugged all of my devices (computer, monitors, router, modem) into the UPS. But after about 10 minutes, the UPS ran out of power and died. Apparently it was using more power than the inverter could put out.

I finally ended up getting a WEN 2000W inverter generator. And it came in very handy today, because the power went out about an hour before I needed to clock in. I cranked up the generator (it’s pretty quiet compared to standard generators), plugged my UPS into it, and ran the computer and other devices off of the UPS. The generator ran like a champ all day (8-1/2 hours) on one gallon of gas! (I probably could have gone longer.) The UPS didn’t fail at all; it worked perfectly.

Here’s what I bought:
https://www.homedepot.com/p/WEN-Super-Quiet-2000-Watt-Gas-Powered-Inverter-Generator-with-CARB-Compliant-Engine-56200i/205825829?MERCH=REC-_-rv_homepage_rr-_-NA-_-205825829-_-N

The generator was $431.23, and the 3-year extended warranty was $75. With sales tax and a few other things I needed to buy (grounding wire, gas can, gas, oil, magnetic oil dipstick), the total came to about $600.

I said earlier that it was pretty quiet. It was a lot quieter than a traditional generator; and no one I spoke with on the phone could hear it running. But it was right outside of my house, about 10 feet from where I work, and my walls are thin; the noise got on my nerves a bit.

I wanted to get a Honda inverter generator – they say that Honda is the best one you can buy. But it costs $1009 at Home Depot, so I decided against it.

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I’ve been meaning to get a backup generator too… and my walls aren’t thin at all.

It’s just, should get one that can run also the circulation pumps for heating, and then the fridge and freezer at least. And that’s a bit more of an electrician’s job, to get those fitted with switchable inputs…

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My solution to using a portable gas generator – is to use extension cords from the 120VAC sockets on the generator; in through a window/door into the house.  Then; I simply move the extension cords around in the house and plug in the appropriate device (fridge, freezer, microwave, T.V., laptop recharger, etc.) as required from time-to-time; being careful not to exceed one circuit load (15 Amp) at any given time per cord; and when nothing else needs it, I leave the fridge and/or freezer plugged in (they cycle On and Off as usual and hold their temperatures well).

No re-wiring necessary.  No concern of other sockets in the house getting live when you don’t intend it, or accidentally turning on too much load.  Like: unplug the fridge, plug in the kettle, make a coffee, then plug the fridge back in again.  Easy …

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That model is really only a 1600w unit (2000w surge).
It’s interesting that they are called inverters. that implies they produce DC via a generator and then use electronics to turn it into a sine wave – would explain why they have sine wave distortion figures. Maybe it’s much cheaper to make a generator than an alternator and electronics are cheap.

cheers, Paul

p.s. the Honda produces ~70% more power so you’d expect it to be more expensive.

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Yep, at those power figures it’s much cheaper to produce a low voltage / high current generator and then push it up with electronics… in part because you can do the frequency setting only at the end stage and don’t need to bother with having that as a ratio from engine rpm or the like.

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Same mechanicals and different electronics setting then gets you the correct voltage and frequency so it can be used in the rest of the world. 🙂

cheers, Paul

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The non-inverter type uses an alternator and must run at a controlled rotational speed to maintain a 60Hz output. These have a governor and run at a constant speed regardless of load making then fuel inefficient and loud. Less expensive units run at 3600 rpm, more expensive ones with more poles in the alternator run at 1800 rpm.

The inverter types can slow down the engine to generate only enough DC power to match the load. The output frequency is controlled by the inverter electronics and is independent of the engine speed. That makes them quiet and fuel efficient.

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Once upon a time when I was a young man, I loved to tackle projects that would benefit me and my family. Are there options you can consider for a combination to at least significanyly deaden the noise maybe even if it means a “small” enclosure for the outside generator and soundproofing your office for your wall(s) without becoming overly expensive?

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I’m looking into building a box to go around it, with plenty of room for ventilation, and with one side open (the side pointing away from me), and then lining it with styrofoam.

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When sound has to make a 90 deg turn to reach you its intensity is reduced by 1/2. So putting a simple barrier between you and the generator will accomplish a lot. Most barriers will transmit some sound energy through them as well as around them so you won’t get the 1/2 reduction in real life. If the barrier itself is a perfect sound attenuator then the only sound reaching you is that going around the barrier.

A box would reduce ventilation and might overheat the generator or cause it to ingest its own exhaust. Not recommended. But a large box with deep sides and top and the back missing allowing plenty of ventilation would require the sound to make 2 90 deg turns to reach you reducing its energy to about 1/4 of its original strength.

However, the ear is a non-linear instrument and the way you perceive loudness isn’t directly related to the level of acoustical energy your ear receives.

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Living in central Florida, hurricane country, a good=sized generator is almost a necessity.  I have a Generac 6500 Watt (8000 Surge) that I have wired into my whole house.  I have to flip a couple of circuit breakers before cranking it up.

It won’t power the water heater or A/C, but fridge, lights, ceiling fans are no problem.  It is located in my shop, 20′ from the house, so the sound is not objectionable.  And it is a generator, not an inverter, putting out 120/240V through multiple outlets.  I have it connected to my house at 240V.

A few months ago a truck took out a power pole a few blocks away, and power was out about 6 hours.  Having the generator was nice.

For power bumps and such I have a pair of CP1000PFCLCD 1000 VA / 600 W PFC Sinewave UPS’s, one for my PC and one for my NAS.  They work quite well in those instances.

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bbearren wrote:

I have it connected to my house at 240V

How do you manage to run your house on 240? PCs I can see, but lights etc?

cheers, Paul

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Paul T wrote:

bbearren wrote:

I have it connected to my house at 240V

How do you manage to run your house on 240? PCs I can see, but lights etc?

cheers, Paul

Over here the standard voltage is 230 V single-phase – 3-phase 400V @ 120 degrees for house main distribution panel.

And what do you mean can’t power a range at 115/120 V? Saw plenty of those last time I was in Britain…

So yeah. For “worldwide” usable equipment you really want a switchable voltage… well for inputs autoranging is possible.

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Paul T wrote:

bbearren wrote: I have it connected to my house at 240V How do you manage to run your house on 240? PCs I can see, but lights etc? cheers, Paul

In the US, most houses are connected using 230/240v – just split the legs and you have 115/120v for everyday outlets.

Can’t power a range or a dryer on 115/120v.

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mn– wrote:

I’ve been meaning to get a backup generator too… and my walls aren’t thin at all.

It’s just, should get one that can run also the circulation pumps for heating, and then the fridge and freezer at least. And that’s a bit more of an electrician’s job, to get those fitted with switchable inputs…

You’ll need a lot of power for the fridge and the freezer. Generac has some nice standby generators, and they run off of natural gas or LP gas, which means if you have a gas line coming into your house, you will always have power.

Here’s a 7500 watt unit (not sure if that is enough for your needs):

https://www.homedepot.com/p/Generac-7-500-Watt-Air-Cooled-Standby-Generator-with-8-Circuit-50-Amp-Automatic-Transfer-Switch-6998/306235149

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Nearly all home appliances like cloths washers, dryers, refrigerators, dish washers use 1/4 or 1/3 hp motors. That’s about 200-250 watts. Not that much. Surge current on starting is more I agree but usually not a problem as cycling appliances probably won’t be starting at the same time. I’m in Florida and use my little Honda 900 watt continuous to power a big screen tv, DirecTV box, DirecTV receiver on the antenna, 2 refrigerators and 2 reading lights at the same time with no problem.

For those using these small generators near their limit make up a short (a foot or two) extension cord with the individual insulated wires exposed. Buy a clip on ammeter they’re cheap. You can clip the ammeter around one of the wires, black or white usually, and read the current being drawn.

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There’s an advantage to clipping your ammeter around the white wire – it’s at ground potential, thus a little safer.

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My house has 240Volt feed from the meter, Sunday evening I lost power to 1/2 of the house, turned out to be one leg/cable from the meter to the breaker panel in the house had defective sheathing and was leaking to ground, not enough to trip the main breaker at the meter but quite enough to drive a few dozen night-crawlers to the surface and cost me a few hundred in repairs/replacement.

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I live in a development about 50 yrs old. Trees planted by the developer have matured and any good wind or thunderstorm can result in lost power. So went with the largest Generac (22kw). Powers the whole house including the A/C and heat. Has a load shed feature that takes the A/C out at generator start-up until load has stabilized. Had a couple of 12 hour outages recently and, other than a 10-15 sec delay at initial fail – never had an issue.

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