Off grid AC power surge test

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BradKW

BradKW

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It was suggested by SW that the Ensupra Electricity Usage Monitor, Power Meter would be able to record the initial power surge my 5000 btu AC unit puts out. It happens to fast for a Kill-o-watt to see it, so I ordered the Ensupra and just tested it out.

Results were interesting.

The maximum surge in watts was 555w ...a surge if between 128w and 187w.  But that was only the result on initial startup...once the unit was warmed up, the surge was only +10w over normal operating.

Not sure what to make of that, but it definitely is much smaller a surge than I was imagining/expecting...

[img=300x450]http://i465.photobucket.com/albums/rr18/Brad_Bleakley/IMG_20170414_140108_zpswyrhjfvz.jpg[/img]

[img=300x450]http://i465.photobucket.com/albums/rr18/Brad_Bleakley/IMG_20170414_140141_zpsh56a9cxc.jpg[/img]
 
Thanks for the report. How you you like in it comparison to kill a watt? Can you hook them in series and see how they compare?

I've yet to use a killawatt or similar, yet.
 
Thanks Brad. How long did you run the A/C? It takes a while for it to build up a full head of pressure and restarting once it is pulling 450w running might be a higher than early attempts. I know if you shut it off it will not start the compressor for three minutes to let the head pressure come back down. Switching from cool to fan and back would avoid the shut down period.

What are the features of the meter like recording total power usage? I should plug the Engel into the Killawatt to get some day to day data now that everything is frozen hard. Then again after I insulate it to see if it really makes a difference big enough to make the effort worth while.
 
I don't find it selling anything or asking for my information. It was cleared by my Norton. I found the whole translated whatever it is to be funny. As I said, brought me a laugh.
 
That link has a whole list of "REVIEWS" on the right-hand-side...........All of the posts read the same way.............just nonsense no content
 
I spent some more time playing around with the two meters today...I would say that the Ensupra is the nicer unit with more features. Think it has battery backup too. For the same price, the KillAwatt does less, it's simplicity could be a positive though...no cycling through to get to the reading you want.

As requested, I daisy chained them together for comparison. Unfortunately this required use of a 50' cord, as stacking them on top of eachother kinda makes it had to read the bottom one. I believe the cord caused one unit to read differently:

[img=300x400]http://i465.photobucket.com/albums/...cts/IMG_20170415_101708_zpscyu0xu9e.jpg[/img]

 But when reversed (swapped placement of units), I got same readings:

[img=300x400]http://i465.photobucket.com/albums/...cts/IMG_20170415_105223_zpsi3ny4p7p.jpg[/img]

Hard to be sure, but I think the Ensupra was reading accurately at all times. But fair to say, it would have required more testing and thought than I cared to give it...

Also interesting is that my initial results from yesterday were duplicated...only one real surge of 100+ watts and it happened at first time compressor kicked on. Once warmed up, all subsequent surges were 10-30 watts...didn't matter if I killed power for 20 min or used the thermostat to cycle compressor. 

From prior testing, the AC draws around 370 watts initially, then gradually raises to 420ish over time...hours not min. If anything, as time goes on the "surge" is less, at least relative to the operating wattage. That is to say, max watts recording of 430w when it was just running at 415w is only a 15w surge.

One conclusion from this for me is that power surge on a small 5000btu AC is basically so small that it doesn't need to be taken into much account when sizing an inverter. Probably far more important is the inverter quality...a 800w Magnum wouldn't even notice this.

I have heard from other's experiences that AC surge can get larger as the unit gets older, so that's something to think about. Also I think it's fair to say that people who operate AC from generators will have different experiences and problems with surge, especially if using Economy idle modes. But a properly sized inverter and battery bank doesn't even notice it...
 
Thanks for posting. I was wondering if my Honda EU1000 generator could power a 5000BTU AC. Seems like it could handle w/o issue.
 
I think that is true, but with a caveat regarding the generator's idle. I was just talking to a friend tonight about the problems he's having with his 8000 btu unit tripping his new Honda 3000i genny when it is on eco mode. Two things are likely in play, one being the AC is 2 years old and has had hard usage, and two being that the idle output is lower than the compressor starting needs.

I'm actually going to give him my meter and hopefully we can see what is going on. But with a smaller EU1000, there might be difficulties as the AC cycles if the genny has dropped into the lower standby idle...
 
highdesertranger said:
that review that Weight posted reads like a spam ad.  highdesertranger
Click to expand...

abnorm said:
That link has a whole list of "REVIEWS" on the right-hand-side...........All of the posts read the same way.............just nonsense no content
Click to expand...

The review reads like it was machine translated from a language that uses different sentence structure (Chinese maybe?).  If you have ever read a newspaper translated by Yahoo or Google you sometimes get totally incomprehensible gibberish.

 -- Spiff
 
There is zero chance that meter is correct, okay well some but not much better than zero. I just went through the process of adding a hard start capacitor to my 5000 btu and even with starting the fan first then kicking on the ac it's still pulling about 7 amps. Without the hard start cap and getting the fan turning first it's pulling 17.9 amps for about 0.35 seconds based on my clamp meter. I would be very, very shocked if the numbers you're getting are the true surge.
 
Could well be you are correct, I have no other way to test it atm and whatever it is, it doesn't cause any issues with my system.

My AC unit operates at around 3.5 - 4 amps, and highest "surge" recorded was about 8 amps. If I'm reading your post correctly, that is in keeping with what you tested after installing the soft start mod?

Could be that my unit has a different compressor or is made to startup more slowly. Or could be that while the new meter I got is recording surges, it's just not designed to capture that fast of a fluctuation with the accuracy needed for this discussion...
 
Agreed on both counts.
How quickly does the Ensupra capture the true surge wattage?
How much would need to be spent to have a tool which can record the actual surge, no matter how brief?

I don't know.

Interseting data it would be, but as Brad says, this was a curiosity tested to help accrue data and his system has no issues powering it.
Perhaps it is not accurate enoughh form member X to buy a source 'just big enough' to power their compressor, but those who seek 'just enough' usually develop a shortfall when things age and 'more than enough' would have been the ultimately cheaper choice.
 
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