WHY ARE SOME INVERTERS PRICED LESS AND WEIGH LESS THAN OTHER INVERTERS WITH THE SAME POWER RATING ?
IS THERE A DIFFERENCE ?
YOU BETTER BELIEVE THERE'S A DIFFERENCE !
SIZE AND WEIGHT MATTER !
Ever wonder why for example some 1500 watt inverters weigh only about 10 LBS and sell for a little over $200.00 and other 1500 watt inverters weigh 40 LBS or more and sell for over $600.00 ?
Back in the early eighties the first U.S. made high quality modified sine wave inverters began to hit the market. Designed and built with heavy duty FETS (Field effect transistors) and massive 60 Hertz based transformers, these units were pretty much indestructible. In fact they were typically under rated so much so that a typical 1500 watt inverter could easily handle a 2000 to 2500 load without missing a beat.
IMPROVED TECHNOLOGY ? WELL IT DEPENDS !
In about the mid eighties U.S. engineers developed a
new inverter technology using high frequency switching technology that
drastically reduced the size and weight of inverters. These inverters did
produce a comparable amount of continuous power but because they used
considerably smaller transformers than the transformers used in earlier designs,
they were not able to produce the high surge currents needed to start many
inductive loads such as motors, pumps, microwave ovens etc.
To overcome the lack of high surge capacity, engineers coupled the outputs of several of these smaller transformers together in parallel. This had the effect of increasing surge capacity but created a much more complex circuit whose reliability depended entirely on the quality of the manufacturing process and the components that went into the construction of the inverter.
The first few U.S. made high frequency designs were all the
rage with their reduced weight and lower cost but all that was about to change
................................
CHEAP DESIGN, CHEAP LABOR, CHEAP PARTS !
Enter the overseas companies with their crude ability to copy or "knockoff" U.S. designs and of course their cheap labor, limited quality control and cheap components.
To this day overseas designed and built inverters continue
to flood the U.S. market. It seems like every six months or so an overseas
inverter company with a familiar sounding name would go out of business and a
new company would spring up. In reality the manufacturers never changed, all
that changed were the inverter names. It's assumed that as soon as the warranty
repairs piled up to the point that the manufacturer could not handle the volume
of inverter failures, they went out of business. Shortly there after the
manufacturer would come up with a new inverter line under a new name and the
process would start over again.
THROW AWAY INVERTERS
We can't tell you how many times our repair department staff have had to advise customers that their out of warranty overseas designed, high frequency inverter was not worth repairing. These were basically throw away units.
Now don't get U.S. wrong, many U.S. and Canadian inverter companies have high quality product built overseas. The difference is that these products are designed by U.S. or Canadian engineers and use high quality components, manufacturing equipment and skilled labor that have been trained by the manufacturers themselves.
A key factor to buying a quality overseas made inverter is
the manufacturer behind the product. Is the company truly a U.S. or Canadian
based manufacturer that's specifically in the inverter manufacturing business or
are inverters just a side line ?
JACK OF ALL TRADES, MASTER OF NONE !
For instance, if a well known manufacturer of lawnmower engines suddenly puts their name on a line of inverters, it's a fairly safe bet that they had nothing to do with the design or manufacture of their inverters. Many overseas inverter manufacturers constantly solicit major U.S. companies to use their well known names on their inverter products. Other overseas inverter manufacturers simply buy the rights to use the names of a familiar sounding U.S. businesses that has gone out of business and will set up distributorships in the U.S. for the purpose of gaining name recognition in the U.S. market.
Don't be fooled, stick with companies that are specifically
in the business of designing and building inverters. In our opinion there are
only three inverter manufacturers that we consider top notch in today's
competitive battery powered inverter market. Those are Xantrex, Outback Power,
and Exeltech.
BACK TO BASICS
Now getting back to high frequency versus 60 Hertz based inverter designs. Setting aside the overseas issue, high frequency inverters that are not designed and built by or have not had their manufacturing process setup by and monitored by a U.S. or Canadian based inverter manufacturer, simply have a much higher failure rate. We learned our lesson years ago after trying several brands of overseas inverters, in fact we still have a corner in our warehouse that's filled with D.O.A. (Dead on arrival) inverters that failed right out of the box that have to go back to their respective Overseas manufacturers for repair.
If you want an inverter for non critical occasional use and are not concerned that the inverter may fail when you need it most and you can afford to keep buying a new one when the inverter fails out of warranty, there are dozens of dealers on the Internet that will sell you an inverter.
Simply put : Heavy duty 60 Hertz transformer based and the
newer hybrid, high frequency/transformer inverter designs are the only way to go
when it comes to reliability, high surge capacity and ruggedness.
BEST OF BOTH WORLDS !
In about 2002 a new design hit the market. U.S. engineers combined the high efficiency of a high frequency front end or driver circuit with the ruggedness and high surge capacity of the 60 Hertz single transformer output design and developed a new line of inverters that outperforms both previous individual technologies. Although only available in a true sine wave configuration, these inverters are the wave of the foreseeable future.
A SIDE BY SIDE COMPARISON OF U.S. 60 HERTZ TRANSFORMER BASED DESIGN VERSUS. OVERSEAS HIGH FREQUENCY DESIGN INVERTERS.
TRANSFORMERS
|
U.S./CANADIAN DESIGN |
OVERSEAS DESIGN |
|
Weight 29 Pounds Transformer from a 2000 Watt 60 Hertz based inverter Large heavy duty 60 Hertz based transformer made of relatively large diameter copper windings. Able to handle much higher levels of heat and mechanical stress. Offers a much higher life expectancy. High density copper mass provides a flywheel effect which provide for much higher surge capacities. Specialized design allows this type of transformer to used to charge batteries when AC current from a generator or other source is fed in reverse through the transformer windings. |
Weight 4.5 Ounces One of six transformers from a 2000 Watt high frequency based inverter. Small high frequency transformer made of very small diameter copper windings. Their lack of mass makes them unable to individually handle high surge currents. Several must be used in order to provide high enough surge capacity. The introduction of several transformers and their drive circuitry in parallel creates a much more complex circuit. Overseas designed inverters do not typically have battery charging capabilities. |
FIELD EFFECT TRANSISTORS AND OTHER COMPONENTS
|
U.S./CANADIAN DESIGN |
OVERSEAS DESIGN |
| High quality U.S., European and Japanese made FETS, resistors, integrated circuits and capacitors are typical in U.S. and Canadian designed inverters. These high reliability components offer higher life expectancy and better overall performance due to tighter tolerances that are within the original design specifications. | Because so many overseas manufacturers are competing for market share, every penny counts ! If a component is relatively close to the original design parameters, believe me it will be used. Forget tolerances and name brand components. If it will work for a while, it'll be used in these inverters. Hey these companies can always shut down and change their name when too many warranty failures pile up. |
MANUFACTURING PROCESS
|
U.S./CANADIAN DESIGN |
OVERSEAS DESIGN |
| You'll find modern pick and place automated robotic manufacturing and quality control processes at these facilities. Facilities that are ISO9001 are the norm not the exception with select U.S. and Canadian manufacturers. Very few components are hand soldered, most components are soldered using modern wave soldering technology. | What's ISO9001 ? During a recent trip to evaluate a potential overseas manufacturing facility, one U.S. based manufacturer advised us that they actually found dirt floors in the manufacturing section of the facility's main building. DIRT FLOORS ! I don't think so ! Because unskilled labor is so cheap, most overseas designed and manufactured inverters are hand soldered which results in non-uniform soldering practices which typically has a negative effect on product reliability |
AUTOMATIC BATTERY CHARGING AND A.C. PASS-THRU CAPABILITY
|
U.S./CANADIAN DESIGN |
OVERSEAS DESIGN |
| As mentioned above the use of a 60 Hertz based transformer
along with some additional circuitry allows for the elegant design of an
automatic 3 stage battery charging system. When A.C. current from a
generator or shore power is applied to the input terminals of one of these
inverter/charger units, the inverter will automatically begin charging the
battery pack with a very precise D.C. current which not only fully recharges
the battery pack but also helps to prolong the pack's life expectancy. Along with a sophisticated battery charger you'll also find a heavy duty transfer relay which allows the A.C. current from the generator or shore power to pass through the inverter and power your loads while you're charging your batteries all without having to flip any switches or unplug any devices ! |
Automatic battery charging and A.C. pass through with an overseas designed inverter ? Better pull out your wallet and make some phone calls because you'll have to order these separate items and figure out how to wire them up yourself ! |
Want to learn more about inverters ?
1-877-498-6527
Now more than ever, If you buy from somewhere else you'll pay too much !
