Fedders 5000 BTU A/C test

Re: Fedders 5000 BTU A/C test

My sisters LG Digital 6K A/C had 110 watts on F3 fan speed (aka high)..

Tuned in for testing.. thanks Cariboocoot..

Re: Fedders 5000 BTU A/C test

^Starting current! An a/c unit. Starting with head pressure might have a huge draw,, and not just for a few milliseconds.

I have a little frigidaire unit, that I run off the eu 1000 once or twice a year. I always start it fan only, then dial in the a/c, the turn up the fan speed. It won't hot start on the little genny, is I leave it on full cool all the time it is running,

Tony

Re: Fedders 5000 BTU A/C test

Most current meters have a sample rate far too slow to capture the actual start up current. I bought a Fluke meter specifically for this purpose. The term they use is "In-Rush".

Here's my 5000 BTU window shaker being tested:





Mine's rated at 600W, which should be about 5A with the fan on high:



With the compressor off, and blower on high, it draws a measly 0.2 Amps.

Here's the actual startup current:



This spike is easily handled by either of my 1800W inverters, and also my 2400W generator.

Furthermore, here's the start up current for my 13,500 BTU A/C unit on my camper, also easily started with the small generator:



The issue with this information is you don't know how much startup current (peak, and duration) your specific inverter (or generator) can supply. Furthermore, no manufacturer is going to share that information about their products either.

This information is useful for me regarding my generator. I have found through testing that it can supply about a 53 Amp surge before going into overload. Wouldn't start my old Dewalt air compressor, but just about any other 15A load. FWIW, the 1800W inverter WOULD start the air compressor. But the inverter was connected to a 900AH battery bank. Compare the potential energy between the battery bank and the generator, the smaller inverter wins.

My larger compressor (RIDGID Tri-Stack) draws 67.8A, but runs on a 15A grid outlet. My generator won't begin to spin the motor. Not tried the inverter yet.

Re: Fedders 5000 BTU A/C test

I have seen much larger A/C units momentarily draw about 8 to 9 times more power on start up than the running load draw.
The power metering equipment I was using was very fast acting, But the surge showed up very clearly for a solid second or 2.
I am thinking running load vs. start up load is not linearly proportional on small vs big units.

Re: Fedders 5000 BTU A/C test

I am going to post this, it's pricey @ $380-$425, but if you are in a situation where it could cost you a lot more to make changes to you system, it might be cheap. I never tried one, but the people who have them swear be them. I know it hard to justify one for a $99 A/C, but the cheapest Marine air you can buy is around $1,200 for a 5000 BTU.

Smart Start

http://www.dometic.com/284244e1-55cd-4bac-b65e-1d54ed1cfc64.fodoc

Re: Fedders 5000 BTU A/C test

niel wrote: »

it sounds like a capacitor and if so that's one of the most expensive ones i've seen.

I saw the inside of it, it's no capacitor the circuit board filled the whole box. There may have been something under it, I didn't see.

Here is a video of it in action and a write up. if you Google it, you'll see lot's on it.

http://www.sailnet.com/forums/gear-maintenance/62158-honda-eu2000i-air-conditioning-3.html

Re: Fedders 5000 BTU A/C test

I bought a LG 8000 BTU window unit this spring. Never ran it on my Kill-A-Watt, I'll have to do that. I can tell you that I bought a Frigidaire 8000 BTU unit first and its quality was awful compared to the LG. The LG was built better and runs much quieter.

Re: Fedders 5000 BTU A/C test

RandomJoe wrote: »

Soft starters are basically a one-shot variable-speed drive. They ramp from 0 to full voltage/frequency on start, usually over an adjustable time, then the load is simply across the line. I've seen quite a few of them installed in commercial HVAC, but there I question their utility. Their cost is often not much less than simply installing a variable-speed drive, so why not do that and get more control over things?

But that is for air handlers and cooling tower fans where varying their speed is actually useful. In this specific case, that probably isn't useful, and a soft-starter is out of circuit once running whereas a VFD is always inline and consuming a bit of power itself so it does have that benefit.

I hear you , they do come from the Boating World.

BOAT = Bring on another Thousand.

New Generator ( $1,000 per KW or More, starting Price 3 KW $5,400 )
New Inverter
More Batteries
New Wiring

To some it may be a cheap alternative ( $400 ) and a steal, To be able to run a 16,000 BTU A/C on a Honda EU2000 is pretty amazing on ECO throttle. Personally, I don't need it, but I would try one for the heck of it. For a RV'er with a 13,500 unit it would be perfect.

Re: Fedders 5000 BTU A/C test

ywhic wrote: »

By both 1800W inverters did you mean Pro Sine 1800 and Pro Watt SW 2000??

Could you possibly do an DC AMP draw reading for surge using the SW 2000 and the same A/C??

Maybe do FAN first (if you can).. then switch it to LOW A/C..

I'd like to see what the DC surge might be usiing the SW 2000..

Yes, the Prowatt SW2000. It's actually an 1800W (continuous) inverter. IIRC, the 2000 Watt rating was for 5 minutes.

I can run a couple of tests comparing the A/C unit on the inverter vs. the grid. Should be the same. I'll have to wait between tests as running the compressor builds up a head pressure, and restarting it too quickly can stall the compressor. I want the numbers to be accurate, and the tests to be fair.

I'll post my results in a couple of days in this thread...

Re: Fedders 5000 BTU A/C test

Sorry for the delay in following up. We have family in town from Scotland, so been occupied. For those who haven't been following along...

I pulled out my cheap Goldstar 5000 BTU A/C unit, and connected it to the Xantrex Prowatt SW2000 inverter for the first test. After I made the measurements, the A/C unit was turned off, and allowed to sit for about 1/2 hour. This ensured the pressures in the compressor were allowed to return to normal before testing the A/C unit on the grid. I didn't want to run the tests too close to one another, with a high head pressure, which would skew the numbers.

The setup:

Attachment not found.

To capture the start up current accurately, I used a Fluke 334 meter with an "In-Rush" features. It makes many measurements in the short (milli-seconds) spike that occurs when the compressor tries to roll over. Most meters are too slow to get an accurate - repeatable number. I bought this meter specifically for this feature.

Here's the start up current when operating the A/C unit from the inverter:

Attachment not found.

Here's the start up current when the A/C unit was operating on grid power:

Attachment not found.

Identical. I tried to measure the start up current of the fan by first turning the compressor off. The spike was so low, the meter stayed in the capture mode, and wouldn't trigger.

Here's the running current of the fan on high (grid or inverter):

Attachment not found.

Pretty much confirmed what I expected. The A/C unit performs the same on grid or inverter power. While my inverter is only $325 (presently), it does make a sine wave cleaner than the grid in my area.

FWIW, there's no perceivable difference in start up sound, or time to get up to full speed, whether on grid, or inverter.

Re: Fedders 5000 BTU A/C test

The current of the fan was so small, it really didn't make any difference. With the RV A/C unit (13,500 BTUs), starting the fan FIRST, then kicking on the compressor, does lower the starting current slightly. With the small 5000 BTU A/C unit, didn't see a difference.

Also didn't notice a difference in the amount of running current with the compressor engaged, and the fan on high or low. Two meters both said the running current still fluctuated about the same amount.

This A/C is so easy to start that my Yamaha EF2400iS generator stays at idle, and barely bumps the throttle momentarily when the compressor engages.

Re: Fedders 5000 BTU A/C test

2manytoyz wrote: »

Most current meters have a sample rate far too slow to capture the actual start up current. I bought a Fluke meter specifically for this purpose. The term they use is "In-Rush".

Here's my 5000 BTU window shaker being tested:





Mine's rated at 600W, which should be about 5A with the fan on high:



With the compressor off, and blower on high, it draws a measly 0.2 Amps.

Here's the actual startup current:



This spike is easily handled by either of my 1800W inverters, and also my 2400W generator.

Furthermore, here's the start up current for my 13,500 BTU A/C unit on my camper, also easily started with the small generator:



The issue with this information is you don't know how much startup current (peak, and duration) your specific inverter (or generator) can supply. Furthermore, no manufacturer is going to share that information about their products either.

This information is useful for me regarding my generator. I have found through testing that it can supply about a 53 Amp surge before going into overload. Wouldn't start my old Dewalt air compressor, but just about any other 15A load. FWIW, the 1800W inverter WOULD start the air compressor. But the inverter was connected to a 900AH battery bank. Compare the potential energy between the battery bank and the generator, the smaller inverter wins.

My larger compressor (RIDGID Tri-Stack) draws 67.8A, but runs on a 15A grid outlet. My generator won't begin to spin the motor. Not tried the inverter yet.

I just noticed you were testing the AC side for the surge..

Can you CLAMP the DC wire to the inverter and see what the spike was from the battery bank end of things??

Re: Fedders 5000 BTU A/C test

I put together a boring 6 minute video last night so those interested can see the window shaker being tested. Warning, contains nerd content.

[video=youtube_share;SxV7rv5wTUg]http://youtu.be/SxV7rv5wTUg[/video]