Cheap Chinese inverter reviews?

hemmjo

Re: Cheap Chinese inverter reviews?

We are using a KISAE SW1210 1000W, 12V Pure Sine Wave Inverter in an installation at our complex in the Dominican Republic. (http://villagemountainmission.org/) I was worried about it at first from all the comments I saw on here, but it was donated to I had to use it. It has been working fine for almost a year. Our system is totally off grid. We have 4 - 275 watt Solar World Panels, Classic 150 controller and 4 Interstate GC2- 232 ah 6v batteries.

As it is, the inverter beeps when it goes into surge mode, and the staff knows to dial back their usage, if they don't it shuts down. It does have low voltage shutdown, but I think that is more to save the inverter from damage due to low voltage than the batteries. It only happens when we have a couple of cloudy days in a row, which only happens in Nov, Dec, Jan.

The system is running a small fridge, small washing machine, 12v LED lighting, small WIFI system, and charges phones and computers. Once in a while we unplug the fridge and run a small drill, grinder or saw. Usually we get the generator our if we need that. The system has been working fine.

I was planning to upgrade to a 24 volt 2k inverter since most advice I got hear tended to downplay the reliability of the KISAE inverter. But since it is working so well, the only thing an upgrade will do is provide more power so the staff can drain the batteries faster. I do wish it was 24 volt input so the batteries could be wired all in series, but its working well as is.


John

jonr

Re: Cheap Chinese inverter reviews?

Put circuit breakers near the power source. If your wires short together, you will know why this makes a difference.

I agree about low battery cut off. The issue forced me to create my own.

GeraldZeng

CALLD said:

For me the biggest problem with cheap Chinese products is actually the lack of reliable information and reviews on them rather than inferior quality. When it comes to "pure sine wave" inverters we all know they are traditionally very expensive. But lately the market seems to be flooded with Chinese TSW inverters with price tags that are truly pricing traditional MSW inverters out of the market.

I for one recently purchased a Ningbo Kosun 24v 2500w TSW inverter for less than $400!

But what about the potential problems that one may encounter with these "quote me happy" inverters?
They are so fresh on the market there is no independent feedback available on most of them.

IMO there are some advantages of going the cheap Chinese route, based on my experience with the Kosun TSW inverter:
* They could incorporate the latest high-performance technology (even though its cheap)
* They can be highly efficient due to the use of more solid state digital components and less analogue/mechanical components. Mine for example has no large transformer.
* Low upfront cost makes purchasing a higher capacity unit is possible giving more freedom to expand and/or lower percentage load on the unit = lower operating temperature.

Issues I have picked up with mine are as follows:
* Unstable AC ouput voltage when loads are under 400watts (16% load). The inverter's voltage regulating feedback loop does not switch smoothly under 16% load and creates sharp irregular amplitude pulses on the AC output. The amplitude pulses do however fall within the 10% AC regulation specification in the manual, but due to their frequency and irregularity it can be very annoying when using CFL or LED lighting as it causes them to flicker. The unstable feedback loop also causes high-current pulses on the DC side which register on the kilo-amper scale even when the average current is only in the single digits. You can actauly "feel" these high current pulses in the battery cables due to the magnetic inductance!
* At loads exceeding 16% the voltage regulating feedback loop stabilises and so does the AC output, however a small amount of high frequency noise is detectable in the AC power but is not an issue for concern.

Other than these issues I have no other complaints and would recommend this inverter for anyone who needs a TSW inverter on a very tight budget!

The only thing that remains to be seen is the long term reliability of the unit. It comes with an 18 month factory workmanship and material defects warranty. Mine has been going pretty much 24/7 for the last 4 months. I would however tend to feel that the unstable feedback loop at <16% loads may be putting additional strain on the components although having no experience in this particular field I cannot say that for sure. As such I try to run >16% loads wherever I can.

If anyone else has experience they would like to share on budget Chinese inverters please post here!

Regards,


Sorry for replying the old thread but I think I may answer this question as I used to be a power designer .

I guess the problem(Unstable AC output voltage when loads are under 400watts ) is that the feedback loop design of the DC-DC boost stage (12V-300?V) is not a good design , you may measure unstable  voltage  on the bus capacitor when it operates at 16% of its full loads  .

By the way , DC-AC is easier to be stable than DC-DC 

jonr

Would be interesting to know if the <16% load stability problem also occurs with purely resistive loads.  If not, a line reactor might help.

w8qf

Just to humor myself I have ordered a Power Jack 100a charge controller. I installed 2400w panel system on the roof of the cabin with 4 Rolls L-16's. When the controller arrives I'll offer it 30 days to prove itself but have serious doubts. At any rate I'll offer my experience here around the end of November.

Dave

hemmjo

Not sure if this thread is still active.  I have to report that the KISAE SW1210 1000W, 12V Pure Sine Wave Inverter I installed in Feb 2014 has been in continuous operation since then at our complex in the Dominican Republic. http://villagemountainmission.org/

It stopped working on Monday, so Feb 2014-Aug 2017, it lasted 3 1/2 years. It preformed flawlessly during that time.  Only kicking off when our staff did something crazy, like trying to run a real air compressor, etc.  We have a generator for such things.

I am going to buy another one for $180.00 to replace it.  That is only 50.00 per year.  I can have a spare on hand at that price.  I wanted to upgrade to 24 volt system when this happened but I cannot go down right now to reconfigure the charge controller.

What kind of service life are people getting from more costly "name brand" inverters?

Marc Kurth

I have four customers who use the KISAE inverter chargers, all are mobile applications and are the low frequency IC Series models. They have been happy so far. The oldest one that I know of is a 2000 W sine wave unit from March of 2014 and is still running in a full time live-aboard RV application. So just under the age of yours.

Another is in an industrial truck powering mobile test/measurement equipment in gas fields. That one is about 28 months old running in really severe conditions - 3,000 watts with a 120 amp charger when plugged into shore power.

Based on this narrow sampling, they seem to make some decent products.

To answer your other question: I often see 8-10 year old Trace/Xantrex and Magnum Energy inverters still running strong.

Marc

Vic

The Xantrex SW +  5548s here are all in their 12th year  --  not an issue with any of they ...   yet.

As Marc said,   these old SW and SW+  inverters have a very good reputation for ruggedness and longevity.

There are several Trace SW 4048s at neighbor's properties,   one dates from 1998,   and has been in continuous use since then.

Another neighbor has a pair of Trace SW 5548s that have been in service since about 2000.

The one thought about your system,  is that hope that you have as much protection from nearby lightning strikes as possible,   although this is probably not the issue with this inverter failure.

Thanks for the report.   Vic

Estragon

I had one Outback die at (IIRC) a little over a year old. Outback shipped replacement boards at no charge, and both running fine since. Stuff happens even to the brand names, but at least the support is generally there when it does.

Mangas

I had four Xantrex SW 5548 + inverters installed late 2005 which ran 24/7 flawlessly for over 9 years.  Impressive reliability and durability.

Replaced one inverter board repaired locally in one afternoon.

lzhome

In my search for a 24v pure sine wave converter in the $500 +/- range all I have found is Chinese or Taiwan branded units such as Coteck which is also branded Go Power etc. And too boot these units, or at least the Go Power brand is "not repairable" in case of a failure. So it is a throw-away due to any failure.
I like Xantrex, had one in my RV for 11 years without failure but they do not support 24v applications in a moderate price range. So the question becomes, is there a quality gap between 12v moderate priced units and upper end 24v units? 

westbranch

I believe the answer is that: there are thousands of 12V units made and hundreds of 24V Units made, supply and demand, plus mass volume production

Saipro

waynefromnscanada said:

Re: Cheap Chinese inverter reviews?

zoneblue wrote: »

Worse is internal fusing leads to complacency and no external fusing, and you have a disaster waiting to happen. These units should not be allowed to be imported.

Interesting point. Both my Xantrex PROsine 1800 watt and 1000 watt inverters have their DC inputs internally fused. Yet they are very highly rated, CSA and UL approved, as well as, according to what I read somewhere in Xantrex info a while back, approved for used in Life Flight operations to power medical equipment.

My Victron Phoenix VE Direct inverter is internally fused too yet has worldwide acclaim across many standards organizations, companies and industries for emergency/backup power/vehicle and on-the-go power supply. They're all internally fused too.

BB.

Internally fusing is not a bad thing... Fuses are designed to be "unreliable" (they pop when exposed to "too much" current). And can fail in normal usage before other parts of the inverter may fail.

AC inverters typically use H bridge setups. Normally, think of the middle of the H as a transformer coil (the "top of the H" is the positive battery bus, the "bottom of the H" is the negative bus). And and in operation, either the upper left+lower right transistors are turned on, or the upper right+lower left transistors are turned on... That creates the "alternating current" you need through the transformer winding(s) to make your 120/240 VAC output voltage. Note that there may be multiple H bridge circuits (parallel current paths)--So internal fusing may be smaller than input bus fusing (i.e., two parallel 40 amp paths are protected by 2x 40 amp fuses--Vs on 80 amp input fuse and/or external fuse on battery bus).

A common failure is (for example) the left upper+left lower transistors turn on at the same time (failure in the transistor control circuits, or even a failure in the power transistors themselves--Silicon devices can fail either open or shorted). When that happens, you have a dead short from the + to - (top of H to bottom of H). Having fuses "somewhere" in the circuit is a very good idea to prevent a molten/flaming puddle of plastic and hot metal.

Normally, an AC inverter has its own over current feedback/protection circuit. If the AC output is shorted (or exceeds ratings), the inverter will electronically shutdown faster than almost any fuse could respond. So, the internal fuses are there for catastrophic failures (shorts/drive electronics failures, etc.).

Do the internal fusing protect the DC input wiring? Yes, to a degree--They protect the battery wiring from internal Inverter Faults. However, faults can occur in other ways too. It is not unheard of for a crimp or binding connection to fail and have a hot battery bus wire fall out and short to metal/ground. Also, poorly installed wiring can get cut on sharp metal holes, or something falls and cuts/shorts the wiring. Having External Fusing/beakers near the + battery post/bus protects against these failures too.

More or less--I treat the AC inverters as "black boxes". I assume that they are designed to fail "gracefully" if something goes wrong internally (and that is what UL/NRTL Listing is supposed to help insure--Proper design, proper manufacturing and test, proper "flame resistant plastics are used during the entire life of the mfg. process, etc.).

So that leaves "me" to look at the safety requirements on the "outside" of the black box. I look at what the inverter needs for input current and power, design and install wiring to support those power needs (too much battery bus current can "melt" even the best design--i.e., 100 amps of fusing vs 1,000 of amps of "unprotected" battery current). And install fusing/breakers to protect the wiring from the battery bank to the the devices/loads (and install bushings to protect against sharp edges, cover battery banks to prevent failing metal objects from causing shorts, locked doors/cabinets to keep kids out, etc.).

Fuses and breakers are "unreliable" (keep spare fuses, use breakers that can be manually reset)--But their being in the system will help reduce the chances of a major failure causing a house fire.

-Bill

Saipro

You're gifted with being able to simplify literally any tech explanation!

BB.

Thank you for your kind words.

-Bill

powersjq

My Wish inverter retains a 12 volt charge at terminals strong enough to leave arc marks, So, I put in a bleed resistor. There's a temporary spot under my car hood to produce power for gas furnace and freezer in an outage. Furnace has an electronic board and requires pure sine wave 110. I just wondered what's in the box. There's a reviewing company that does destructive analysis of cell phones. They should get at this inscrutable black box.

BB.

AC inverters may have large value capacitors on the DC input to perfect long/small DC wiring having to much resistance to supply the AC switching circuit inside the inverter.

Having a discharge and/or charging circuit for the input capacitors is not common, but it's sometimes done.

Instead of using a standard resistor, sometimes an NTC resistor is used to stop current surge on starting or connecting on some equipment (negative temperature coefficient resistor. Cold NTC has high resistance to limit starting surge. Then gets hot and has low resistance for running).

But I would doubt that anybody uses NTC resistors on the DC inverter input... Just not very practical.

Bleed resistors are sometimes it's used on high voltage capacitors so that a service person is not shocked when working on a powered down unit.

Bill

slywuf

I don't know if there is still interest in this thread regarding "Cheap Chinese inverters" but in case there is, I wanted to let folks know about the experience that I had recently with one.  This particular unit is a hybrid type that contains 2 MPPT solar chargers, an AC charger plus 6000W inverter and transfer switch.  Manufactured by Yiyen Electric Technology Co.  https://www.yiyen.com/products/pure-sine-wave-inverter/     Although not exactly "cheap" it did cost me about $1800.  I was hoping for the performance to be as advertised, but was quite disappointed.  If anyone is interested in the details of my experience with this unit, let me know and I can expound greatly, but the basic problems that I ran into was its poor ability to manage the output of my two solar arrays, which output about 2700 watts each.  More often than not, the inverter would not use all the power available from the arrays.  It might choose to use just one array or maybe neither to charge the batteries and run the loads.  It would instead just run the batteries down and ignore the power available from the arrays.  Sometimes the inverter would properly use the arrays, but there never seemed to be a logical pattern for how it operated.  Another big problem was trying to get technical support from the factory in China.  The support there did not offer a solution other than to buy another product or add external MPPT chargers.  Bottom line is - STAY AWAY from this company and their products!  There are much better products available now right here in the good ole USA that are light years ahead in performance and reliability.  You will pay a lot more money for them compared to the Chinese stuff, but in the long run, it is well worth it to have equipment that functions properly.

Ralph Day

Tried and true...Outback, Midnite, Schnieder, Magnum, others I can't remember (sub 2K inverters)

mcgivor

Then again, I lost a quality inverter  to a gecko  and purchased a cheap store branded 2000W temporary replacement,  knowing full well  it came with a bumper sticker warranty with zero support, it has been in service for over 4 years on 24/7, it is capable of powering everything I have with the exception of the microwave. For the $250 spent it has paid itself off, I did however cover all entry points with stainless steel  mosquito mesh to keep critters out, lessons learned. 

Bossrox

Has anyone run across an inexpensive decent brand that can do 5-6kw on 24v?