Why is my inverter freaking out?

[Naio]

I have a 1500watt HF MSW.

I don't use it often, so I am not acquainted will all of its oddities.

Last year I tried to use it with my 65w fridge at it would not work (alarm sounded). Although it had no problem with 300w electric heater!

I upsized the cables, tested it with the fridge, and it was fine.

I pulled it out again last week, and it would not run my mattress pad, which it previously had no problem with. Sometimes it would not even run a 15w heating pad! Other times it would run two of them.

All comnections are tight, battery fully charged. Inverter fan is not coming on. Plastic case feels warm in one spot, but not hot.

Suggestions? I am baffled.

[westend]

Don,
Not so sure these Xantrex are as low as "throw away". I've been running the 1000W Xantrex Prowatt for a couple of years and it seems to do it's job well. It handles my little fridge's startup load great and I've never heard the fan. One feature I didn't appreciate that I now use are the USB charging ports. They're too convenient to not use, lol.

[MEXICOWANDERER]

road-runner wrote:

MrWizard wrote:

Tripplite powerVerters
are technically MSW and are listed as such
BUT are specifically designed to run motors and actually have a modified sine wave
NOT a Square wave, mine has been running my fridge for over 5 years
they include heavy transformers and filtering

they are NOT $99 Choppers making square wave with lots of noise

I'd sure like to see a picture of their waveform. I've never found an MSW inverter that doesn't follow the 4-step (+v,zero,-v,zero) waveform with nothing else in-between. The only difference I've seen is that tripplite calls it "PWM sine wave". I'm not meaning to knock tripplite MSW inverters, they have good reviews. Without seeing a picture of the output it's hard for me to imagine what's different about them.

Mr Wizard is right on the money - square wave. Until an inductive load was introduced. Upon which the scope screen looked like gorilla scribbling. Most MSW machines will revert to square wave at high loading. Then there's HF grade - Picasso Wave. Stare at that wave and you'll fall off your stool.

[pianotuna]

Naio,

It is time to move up to a decent pure sine wave before any other item in the RV gets damaged. Bestconverter sells "throw away" Xantrex pure sine wave units. I'd be tempted to go to 2000 watts and only use 50% of the capacity.

http://www.bestconverter.com/Prowatt-SW2000-Sine-Wave-Inverter_p_375.html#.Vu7WlDFP61s

[joebedford]

x

[road-runner]

Here's a picture of the output claimed to be from a Tripp Lite device providing "PWM sine wave".
Looks like any other MSW waveform to me. It would be nice if somebody here with a Tripp Lite MSW inverter could post a picture of their actual waveform. From what I've been able to see so far, the waveform looks the same as any other MSW inverter's waveform. The full article the above picture is from is here: http://www.repeater-builder.com/backup-power/ups-test.html
The Tripp Lite unit is covered at the end of the article.

[naturist]

MSW inverters work fine for things that are simple resistance loads: light bulbs, simple heaters. But they are death for things with any sophistication. Some things with motors do ok, but if it has any kind of electronic controller, forget it.

MSW inverters are cheap, cheap, cheap to buy. And I even have one, a 400 watt unit that powers my Mac laptop just fine BUT ONLY because of the particular type of power brick that computer has. Another make or model computer might not work.

It is highly recommended folks save up their pennys and spring for a PSW inverter if they fancy having no issues in the future.

[CJW8]

MrWizard wrote:

road-runner wrote:

MSW inverters are not the same and Harbor Freight inverts are very square wave.

What other MSW inverter is less of a square wave?

Tripplite powerVerters
are technically MSW and are listed as such
BUT are specifically designed to run motors and actually have a modified sine wave
NOT a Square wave, mine has been running my fridge for over 5 years
they include heavy transformers and filtering

they are NOT $99 Choppers making square wave with lots of noise

Tripp Lite uses PWM applied to the MSW and filtering to achieve near sine wave output. I think it looks like a saw tooth sine wave.

[CJW8]

double post

[road-runner]

MrWizard wrote:

Tripplite powerVerters
are technically MSW and are listed as such
BUT are specifically designed to run motors and actually have a modified sine wave
NOT a Square wave, mine has been running my fridge for over 5 years
they include heavy transformers and filtering

they are NOT $99 Choppers making square wave with lots of noise

I'd sure like to see a picture of their waveform. I've never found an MSW inverter that doesn't follow the 4-step (+v,zero,-v,zero) waveform with nothing else in-between. The only difference I've seen is that tripplite calls it "PWM sine wave". I'm not meaning to knock tripplite MSW inverters, they have good reviews. Without seeing a picture of the output it's hard for me to imagine what's different about them.

[Naio]

Thanks, Mex.

Pthooey!

[MEXICOWANDERER]

Naio every HF inverter I purchased from 175-watt to 1,000 watts did similar acts of insanity before they went to inverter purgatory. They are "Yugo" grade inverters. All of mine went into storage seemingly working OK then went postal when they were reconnected.

Chew and spit

[MrWizard]

road-runner wrote:

MSW inverters are not the same and Harbor Freight inverts are very square wave.

What other MSW inverter is less of a square wave?

Tripplite powerVerters
are technically MSW and are listed as such
BUT are specifically designed to run motors and actually have a modified sine wave
NOT a Square wave, mine has been running my fridge for over 5 years
they include heavy transformers and filtering

they are NOT $99 Choppers making square wave with lots of noise

[RoyB]

I got a couple of POWERWARE/EATON 5125 Rack mount UPS units from work that are 1500WATT SINEWAVE units. These have the internal battery packs that will run several things here in my radio/computer room for about three hours before going into low DC alarm. These have the external 48VDC external DC POWER connectors on it and I was wanting to add some external batteries to it to make it run my room longer when we have power outages... I don't think these units cost much on the surplus market... I have clocks and fans and all kinds of regular 120VAC items plugged in the 120VAC power strips in the radio/computer room. Clocks never miss a beat,,, Routers-Computer- monitors - HDTV and radio circuits don't even blink when it switches over... Just doesn't stay on for a long time. Gives me time to normally shut things down I reckon...

Another project to work on one of these days haha... We used these at work to run our telephone/Internet interface circuits for comms gear...

These being portable rack mount units sitting on my floor here I could drag them along in my OFF-ROAD trailer just fine. they sure are a heavy thing however haha... Never done that...

Roy Ken

[CJW8]

I ran a large dorm style refer for a couple of weeks on a Xantrex 1000 W MSW inverter while my absorption refer was being repaired. I also occasionally powered my TV and speaker system with no problems. I suspect the Xantrex MSW inverter is a cut above the HF one.

[road-runner]

MSW inverters are not the same and Harbor Freight inverts are very square wave.

What other MSW inverter is less of a square wave?