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.

[MEXICOWANDERER]

A Warm Puppy works 🙂

[Naio]

Thanks, everyone, for the input :).

I ran some tests on mine. Could not get it to do the same thing twice. On testing day it was perfectly fine with the freezer, and fine with the heat pads MOST of the time. Again, no pattern. Mex's comment about the HF ones being wacky in general was most helpful. At least I know it is not me ;).

As for buying PSW, I will if I find I want an inverter often. But so far it's only been a few nights a year. Thing is, when I want that mattress heater I really want it!

[CJW8]

The specification most overlook in MSW inverters is THD, total harmonic distortion. With MSW inverters it is anywhere from 25 to 50%, depending on the type of load, and every bit of that is wasted power.

[MEXICOWANDERER]

Looks like the inside of an Australian's dock worker's mouth...

The original Tripp Lite was 400 watts - $550.00 Wave form, absolutely square.

The most perfect looking sine wave isn't worth snot, if it plays permanent possum.

The world of inverters a depicted by cheap inverter manufacturer's is a gold plated tribute to Herb Tarlek. They lie like a wet rug. I rob the heatsinks out of cheap inverters, even though they buzz and lights flash. I know their lifespan will be as long as a group of Libyans hoisting RPG's under a cloudless sky.

[road-runner]

Here's another picture of Tripp Lite "PWM sine wave" output. This one is claimed to be from a PowerVerter Plus Industrial Strength PV-1250FC, and looks like standard 4-step MSW to me:


The source of this picture is http://www.centralmiarc.com/docs/Reviews/dcacmaha.pdf.

A summary of the article:
- 3 MSW inverters were tested.
- All 3 have the standard 4-step MSW output waveform.
- The TrippLite inverter's output had a significantly cleaner output waveform than the others, resulting in significantly reduced conducted emissions.

I'm hoping the waveform picture is correct as there are a few things in the article that in my eyes question its authority:
- The article says the PV-1250FC weighs 10.5 pounds. TrippLite says 23.2.
- The article fails to mention that output waveform of all MSW inverters changes with the DC input voltage.
- I've scoped about a half dozen MSW inverters (mostly cheap ones) and have never seen anything remotely close to the noise level the article shows on the two other MSW inverters. There's got to be something more than "cheap inverter" behind this.
- The article says "MSW inverters produce stepped square waves that resemble a sine wave". I agree with this about as much as a motorcycle resembles a diesel pusher.

[wa8yxm]

NinerBikes wrote:

wa8yxm wrote:
There is an excellent article on MSW inverters in the ARRL's QST archives, problem is you need a membership to view.

Some are .. kind of bad.

But Compressors take a LOT of startup power. the slightst amount of resistance in the wires or connections, and the internal resistance of the battery, become significant at these power levels.

As to the smaller devices, No clue, but I'd put a volt meter on the input, analog please.

Perhaps a link?

That would require way more research than I wish to do today, plus I think: YOU MUST BE A MEMBER.

But in any case Here is the link to to the article.

They reviewed several Inverters both PSW and MSW. and gave some excellent comments.

[westend]

pianotuna wrote:
Hi Westend,

I call them throw away because Xantrex refuses to sell parts for repairs. You have to know a guru who can fix them such as our friend in Montana. I think they are a good bang for the buck--just get one large enough that it will never be overloaded and it will last a long long time.

Canadian Tire sells them rebranded from time to time at $199.00 for a 1000 watt. I have one sitting in my pass through storage to use as an emergency back up, should the 3k Magnum decide to let out the magic blue smoke.

westend wrote:
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.

Don,
Gotcha, they are not top of the line like a Magnum or other. I solder up some caps and resistors occasionally so stuff like this inverter is small spuds.

[MrWizard]

road-runner

i can't help or understand their adv department
but they are not the same on the inside
look on the net for the pictures and the weight specs
i'm not opening mine up to show you the differences

mine is for motors and power equipment, industrial grade, not for putting under somebodies desk, and there is a difference
BTW how many years ago for that web page being posted,
things change

[pianotuna]

Hi Westend,

I call them throw away because Xantrex refuses to sell parts for repairs. You have to know a guru who can fix them such as our friend in Montana. I think they are a good bang for the buck--just get one large enough that it will never be overloaded and it will last a long long time.

Canadian Tire sells them rebranded from time to time at $199.00 for a 1000 watt. I have one sitting in my pass through storage to use as an emergency back up, should the 3k Magnum decide to let out the magic blue smoke.

westend wrote:
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.

[NinerBikes]

wa8yxm wrote:
There is an excellent article on MSW inverters in the ARRL's QST archives, problem is you need a membership to view.

Some are .. kind of bad.

But Compressors take a LOT of startup power. the slightst amount of resistance in the wires or connections, and the internal resistance of the battery, become significant at these power levels.

As to the smaller devices, No clue, but I'd put a volt meter on the input, analog please.

Perhaps a link?

[road-runner]

MrWizard wrote:

you will NOTICE
this a computer APC, not a PowerVerter designed for running motors
computers have 'switching power supplies' and are not affected by wave form
my powerverter weighs 22# and there are NO batteries in it
its all Iron and Copper

Please pardon my snippiness, you will NOTICE that this picture is of what Tripp Lite calls PWM sine wave, the same name given to the PowerVerter output. Pardon me for "assuming" that PWM sine wave means the same thing across Tripp Lite's product line. Somebody with a Tripp Lite MSW inverter, please post a scope picture of the output.

[MrWizard]

road-runner wrote:
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.

you will NOTICE
this a computer APC, not a PowerVerter designed for running motors
computers have 'switching power supplies' and are not affected by wave form
my powerverter weighs 22# and there are NO batteries in it
its all Iron and Copper

[wa8yxm]

There is an excellent article on MSW inverters in the ARRL's QST archives, problem is you need a membership to view.

Some are .. kind of bad.

But Compressors take a LOT of startup power. the slightst amount of resistance in the wires or connections, and the internal resistance of the battery, become significant at these power levels.

As to the smaller devices, No clue, but I'd put a volt meter on the input, analog please.

[time2roll]

Go Power SW replacement $466