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Old 06-15-2011, 05:19 PM   #1
Bolster
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Default Refrigerator on a Generator - puzzled by amps and watts...

Hi folks, I'm trying to figure out if I can run my existing refrigerator on my existing Honda EU2000i generator. Likely not, but I'm puzzled about something.

The mfgr of my refrigerator, GE, says my 110v fridge needs a 15 amp breaker and 3000-4500 watts of power. That doesn't compute. 3000 watts of power would be 27 amps. So how is this fridge running on a 15 amp circuit without tripping it?

More digging revealed that the running wattage needed for the fridge is 1800 (OK, that's about 15 amps), but startup could demand 3000-4500w. Sounds like I won't be able to run this fridge on my EU2000i, which is only about 1600 continuous.

But still puzzled over that 15 amp thing. How can startup not trip 15 amps?
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Old 06-15-2011, 06:17 PM   #2
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

Your genset will run it just fine. Running watts will be more like 300. You can, and I have, bought this little device called a kill-a-watt meter that measures 110 volt loads and tells you thinks like KWH consumed, volts, hertz, watts, etc. I've put this on my fridge and found that the running watts is very low.

Startup surge will be much higher but nowhere near the rating for that Honda. Test it out. Nothing to loose.

The home's breakers are slow-blow to allow for short term surge loads. So even if you did pull 25 through a 20 amp breaker it might not pop right away.

Now the microwave, that puppy pulls down some watts.
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Old 06-15-2011, 06:21 PM   #3
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

That's interesting.

I got the impression the GE help line (who answered my questions) were a group of die-hard ignorant know-nothings, reading canned answers off a sheet of paper. At one point I remember asking, "Don't you want to know which refrigerator I own?" When I asked about the discrepancy between breaker amp recommended (15) and their stated watt load (4500, or 41 amps), their answer was, "Because it's designed that way." The idea of a slow-blow fuse wasn't in their vocab. But even with a slow blo fuse, the discrepancy is huge...it would require a 15 amp fuse to be allowing 41 amps to pass during startup.

So you think I can run a fridge/freezer (it's both) off my little 2000? You don't think startup will kill it?

Found your gizmo, cool.
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Last edited by Bolster; 06-15-2011 at 06:28 PM.
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Old 06-15-2011, 07:18 PM   #4
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

i bet it will work fine, doesnt your generator have a surge rating as well as a continuous? i got one of those kill-a-watt dudes, found my refrigerator only uses 120 watts running, startup is around 1500 i know mine isnt the same model as yours, but 41 amps is crazy.

that little watt meter can tell you what it draws though.
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Old 06-15-2011, 09:06 PM   #5
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

I think the 3500 to 4000 watts has to be incorrect. That is more than a water heater.
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Old 06-15-2011, 09:25 PM   #6
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

Quote:
Originally Posted by Bolster View Post
That's interesting.

I got the impression the GE help line (who answered my questions) were a group of die-hard ignorant know-nothings, reading canned answers off a sheet of paper.
But they speak English at least as their second or third language!
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Old 06-15-2011, 09:25 PM   #7
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

Quote:
Originally Posted by dtt454 View Post
i bet it will work fine, doesnt your generator have a surge rating as well as a continuous?
Yeah, the honda EU2000i is rated 1600 w continuous, 2000 surge.
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Old 06-15-2011, 09:44 PM   #8
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

I think there's an extra zero on the power requirement figures.
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Old 06-15-2011, 10:15 PM   #9
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

I bought one of those meters, just out of curiousity. I found out that my old chest type freezer used more power at the warmest setting (empty, just on stanby) than my new, noisy upright. So much more that I decided to take the chance of unplugging it, even if decides not to start up when I plug it in temporarily in the future.
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Old 06-29-2011, 09:41 AM   #10
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

No, the 3500 to 4000 sounds incorrect. Maybe there is a decimal point there that we are not seeing?
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Old 06-29-2011, 10:05 AM   #11
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

the 3500 to 4500w is the current drawn when the compressor starts. Doesnt trip the branch circuit breaker due to inverse time delay function in the breaker. you will probably need a generator with this size surge capacity.
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Old 06-29-2011, 10:44 AM   #12
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

Unless you have a really old, inefficient fridge, 3000-4500 watts sounds really high. I have a 2400 watt generator that I've run 2 fridges, lights, and a television from, and the generator wasn't running very hard, even with the compressors on the fridges running.

But like someone else suggested, buy a wattage meter and you can read it for yourself. The main thing I would check is the wattage when the compressor turns on.
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Old 06-29-2011, 11:03 AM   #13
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

i dont know that a kill-a-watt is going to capture motor inrush (maybe it does -dont have one) i would use a clamp on ammeter that has a peak hold function.
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Old 06-29-2011, 11:53 AM   #14
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

The starting current draw peak can be some 3-4 times higher than the running current draw.
If you use any ampmeter and read off the running amps my guess is that if you multiply this figure with 120 you get about 200 VA. If you then use a kW meter which takes phase shift in account you will get a power draw of 150 W.
Any decent home generator will start and run this.
A 2000 W refrigerator is likely to be something in a restaurant or a shop.

Finally 1000 VA (S, appearant power) at a power factor of 0,75 ( cos fi, the cosine of the phase angle between voltage and current) equals 750 W (P active power)
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Old 06-29-2011, 03:20 PM   #15
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

Most fridges have heating elements to keep the door frame from sweating. Some have a switch to turn this off. They also have a heating element that is part of the freezer's defrost cycle. I'm sure they are adding these, plus the light bulbs, and the ice maker motor and its heating element also, into the total. Rare is it that all of this happens at one time.

Unless this is a huge fridge (way over 20 cu ft) the little Honda will run it just fine. Get a good heavy 12 ga extension cord and try it. Listen carefully for compressor startup and if it runs OK go for it.

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Old 06-29-2011, 05:41 PM   #16
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

I can't knock the Honda generators. They are certainly the Cadillac of small generators.

There are some alternatives, in the same price range that put out more power.

Yamaha EF2400iSHC

Boliy Pro3600Si
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Old 06-29-2011, 05:54 PM   #17
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

Quote:
Originally Posted by mrb View Post
the 3500 to 4500w is the current drawn when the compressor starts. Doesnt trip the branch circuit breaker due to inverse time delay function in the breaker. you will probably need a generator with this size surge capacity.
I trust this answer and I have have heard something very similar.

mrb knows his stuff.

I put generators on jobs for people who have power outages and on several occasions neighbors and nuts have gotten power cords into my units and burned them up. I run 3500 max amp generators, I suspect that the nuts are plugging in their refrigerators into my units and the generator just never can cope with this surge and revs itself into oblivion. Of course, the offending neighbor of the customer is never around when I pull up to my smoking mess, but I do see an occasional window treatment motion on the home next door.
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Old 06-29-2011, 08:54 PM   #18
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

I have a 2 year old Kenmore Fridge that I run on my Eu2000I with out a problem.

I didn't bother with calculations. I just plugged it in and it worked fine.
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Old 07-01-2011, 11:30 AM   #19
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

I wish the peoples neighbors would have had one of those.
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Old 11-03-2012, 07:37 PM   #20
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Default Re: Refrigerator on a Generator - puzzled by amps and watts...

I have a related question. I'm trying to see if my 800/900 watt Harbor Freight generator will power my Kenmore model 4126 refer. I want a backup when the power goes out.

It seems to need 8-10 A for a second to start. On the generator, it draws about 6 A for 10-30 seconds, then I hear a click and no more current is drawn. While it is drawing 6 A, the voltage drops from 120 v to 100 v. After a few mintues, it tries again. After a few tries, it finally starts and draws 1.2 A while the compressor is running.

I interpret all this to mean I the generator is not big enough. I suspect a slightly bigger one (1000/1200 watts maybe) would do the trick. Am I right?

And yes, I am using a fairly short 12 ga extension cord between the generator and the refer.
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