Bestek 500Watt Pure Sine Wave Inverter - Use Discretion

[user 423]

I hope it's just a manufacturing defect, we're happy with all of our Bestek items. 

Even though I had trouble with the 500w model, the 1000w MSW Bestek I've had for a couple of years has been fine. I use it to power a jig saw, small circular saw,angle grinder or 3/8" drill. They do sell a lot of inverters.

 

[PeterPiper]

Again, a car with two flat tires WILL STILL get you to the market.

Just because "They work" does not mean they "work well"

You really need an oscilloscope to determine if they are good or not.  The difference is in efficiency and harmonic distortion.

I have several inverters that work.....but they also have lots of harmonic distortion and they draw more power from the battery to operate AND they inflict damage on many things they operate.  Most often it's in the form of excess heat.

True, it might work for years with no problem, but it's also true they can shorten the lives of devices powered by them as well as use significantly more energy when in use.

I suggest few people know the difference.  Many times only an oscilloscope can clearly reveal the problems as you see in the video and pictures I posted......it seemed to work just fine.  I even load tested it to 480Watts.  No problem.

But lets say you are in a camper with limited power resources.  An inverter with a poor sine wave can use up to 30% more power from your battery.  Anything you run with it that has any kind of motor will run hotter and have a shorter life.

So it's a matter of personal preference.  It's like buying a highly efficient solar panel vs one that is low efficiency.  Both work, but one is better.

Sometimes a cheap inverter is a good trade off between budget and needs.  Manufacturers KNOW that few people will ever check them with oscilloscopes.

So like driving an expensive Porsche ....with bald tires....you may be "happy" with it....but that doesn't mean it's operating efficiently or safely.

 

[PeterPiper]

Ok, got the 2nd one.

EXACT same oscilloscope results, exact same load results.  The thing seems to work well in spite of the oscilloscope results.  I've decided to keep the 2nd one.    Hopefully it will last a few seasons.

Here it is with my Kill-A-Watt device attached holding 499Watts for 10 minutes.

 

[user 37446]

It seems ok then, price point...

 

[PeterPiper]

It seems ok then, price point...

Yeah,
It's not perfect so you're getting what you pay for.
The sine wave under load seems ok so for $65.00 I guess it's ok.

Let's see how it stands the test of time.  I'm hoping for at least 2 years.  After that is gravy.

My only advantage is that I'm able to diagnose and repair many circuit problems so if it does fail, it's likely I can fix it.
For that matter, after I open it I might be able to find out why it's got these oscilloscope issues and add filters or better components to resolve the issue.  Not sure, but will look.

 

[user 423]

Bump:

A while back I bought a little DROK USB tester as I wanted to check the voltage on the several USB charger/power adapters I have.

I dragged out the defective 500W MSW I mention in post #2 and found that the outlets on it were 4.87 volts.

That's really not off by that much but a USB fan plugged into those outlets runs slowly and oscillates up and down in speed. The tester showed the fan draws about 0.50 amp which is lower than the 0.65 amp spec on the label.

Both USB outlets stay energized even when the inverter is off. Is this normal?

 

[MotorVation]

Both USB outlets stay energized even when the inverter is off.  Is this normal?

I have a modified sine 1200 watt Bestek inverter. The USB ports are always live.

I use it to make coffee twice a day, other than that I keep the power button off. I paid about $65 bucks for it on Amazon a couple years ago. Now it's about $100 I think. I've never had a problem with it

 

[PeterPiper]

Bump:

A while back I bought a little DROK USB tester as I wanted to check the voltage on the several USB charger/power adapters I have.

I dragged out the defective 500W MSW I mention in post #2 and found that the outlets on it were 4.87 volts.

That's really not off by that much but a USB fan plugged into those outlets runs slowly and oscillates up and down in speed. The tester showed the fan draws about 0.50 amp which is lower than the 0.65 amp spec on the label.

Both USB outlets stay energized even when the inverter is off.  Is this normal?

For that unit, yes.  The USB ports on mine also stay energized even when it's switched off.
tbh, I like that feature.

 

[highdesertranger]

Wouldn't that mean it's drawing power all the time? Highdesertranger

 

[B and C]

Probably no more power than a standard USB outlet. It probably bypasses all in inverter circuitry and has its' own and separate.

 

[speedhighway46]

In the world of PSW inverters, the rule of “you get what you pay for” REALLY applies. And, if you are buying off E-Bay you are especially vulnerable. There is a quite a lot of Chinese poor quality units offered at attractive prices which will suck you in.

What to do? Determine the size unit which will fulfill you needs, and then on-line and find a domestic company and look for their higher prices. Hart Interface come to mind, but there are several others. Even though most of these units are make over seas, they are of domestic design and engineering, and provide an additional layer of quality control the cheapie units don’t have.

Find a good unit and expect it to cost more than most units of a like size. It will provide years of service, will have a first class waveform, and won’t become a doorstop after 50 hours of use.

Just my opinion . . . based on my actual experience.

 

[highdesertranger]

Hey Speed good to hear from you again. Highdesertranger

 

[speedhighway46]

Hi HDR! Hope you are well; thanks for all you have been doing to support the group!

 

[Cammalu]

Speed? How are the little doggos?

 

[speedhighway46]

Speed?  How are the little doggos?

Hi Cammalu! Thanks for saying hi! Be safe.

 

[CC58]

I have a 300W pure sinewave Bestek converter and oscilloscope. I pulled 270W out of it and the sinewave didn't change at all and looked as good as my house voltage.