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The Norman, Oklahoma based Bergey Windpower has been in the wind energy business since 1977 under the watchful eye of co-founder Karl Bergey. The more visible co-founder and president,Mike Bergey is typically seen as the voice of the company and gets most of the press.
The Bergey product line has varied over the years with past achievement such as the BWC 850, BWC 1000 and BWC 1500 which are now laying in the discontinued pile. Of these, we have personally witnessed a neighbors BWC 1500 hold up for years under some very adverse wind conditions. When it became apparent that it was in need an overhaul, our friend switched to a Kestrel. Though the Kestrel is working fine, he laments the passing of the BWC 1500 occasionally remarking about the years of fine service the BWC 1500 provided.
We do notice that
things are quieter around here since his BWC 1500 came down. During our
whipping 30-50 mph winds that can last for weeks, we don't hear the
Kestrel like we could the Bergey. In these conditions the Bergey
"helicopter" could be heard at our house almost a half a mile away.
Currently
there are two products on the assembly table, the XL.1 and the Excel.
The XL.1 essentially replaced the BWC 1500 which was discontinued in
2002. The Excel has been going strong since its release over 20 years
ago and will probably be going nowhere near the junk heap anytime soon.
In
the field, Bergey has a reputation of being a reliable performer with
widespread name recognition. They are not advanced, state of the art or
based on cutting edge technology. Rather they are actually what could
be considered rather old school when compared to the new machines
currently finding their way into the wind energy marketplace. Old
school or cutting edge, the Bergey turbines have one thing going for
them, they work. They currently have numerous installations operating
both on and off the commercial power grid and boast installations in
the U.S. and over 50 countries.
The Excel which appeared in 1983 is based on the original BWC 1000, the first production model Bergey offered in 1980. Currently over 1,600 Excel turbines have been sent to the field. It is available in either a grid tie or battery charging model. The Excel sports some serious weight, low RPM and simplicity. That is a good combination if you need some serious power but don't care to step into the mid-range utility turbines such as a Vestas or Northwind. The Excel also offers a less complicated design and a lower maintenance load than the venerable Jacobs.
The Excel has one major drawback, as we see it. For
all its simplicity, the Excel is rather large for a machine that
protects itself by the furling method. Further, its furling speed is
rather high at 35 MPH. A lower furling speed would provide less power
but it would subject the turbine to less stress. We would assume that
lower stress would lead to a longer life expectancy and fewer interim
problems. Evidently Bergey has made allowances for this by building a
tough machine since there are not widespread reports of repeated early
structural failures.
The XL.1 is a side furling machine that fits rather nicely in the small turbine market. Available since 2004, it only comes in a 24 volt battery charging model. The rotor diameter is 8.2 feet with pultruded fiberglass blades. The rated output is 1000 watts at 24.6 mph and a rotor speed of 490 rpm, however the full furling wind speed is a bit higher at 29 mph. Due to the difference in the rated wind speed and the furled speed, it is not uncommon to hear of outputs up to 1,300 watts during high wind conditions.
The rectification of AC to
DC takes place in the nacelle. Two wire DC runs down the tower to the
charge controller. The Bergey charge controller features such things as
low-end boost and slow mode. The low-end boost is said to give superior
low wind speed performance. The slow mode is for idling the rotor when
the batteries are full. The controller also comes with a 30 amp solar
control unit built in. The XL.1 turbine is made in China.
Bergey - The Company
The
most noteworthy comment we have about Bergey is that they finally
updated their website! It is actually easy to navigate and pleasant to
visit. And interestingly I first thought that I had somehow landed on
the Lowes homepage. That is Lowes, the home improvement company. The
soft blue background and Lowes banner at the top must have caused the
momentary confusion.
While the new website
design is a welcomed relief, it is basically the old site in new
clothes. There doesn't seem to be anything really new in the technical
department concerning wind power. On the other hand, it does have a
nice, fluffy feel to it.
So, what we find in the
new website re-design may be of no small coincidence. You can actually
buy an Excel through Lowes Home Improvement Centers in California,
Hawaii and North Carolina. This move will likely be a boon to Bergey.
Getting your product out in front of the number of people that visit a
store like Lowes is no small event.
Of course
information regarding the turbines specifically says "Bergey 10 kW wind
turbines". Oddly, there is absolutely no mention of the XL.1. Also,
does this exclude the Excel-R 7.5 kW battery charging model? If the
Excel-R is excluded that would actually reinforce the perception that
off the grid people are wild, lawless renegades that are best avoided.
It would be better to deal with such people in a quiet office far
removed from the public eye. Plus, what kind of decent outlaw would
shop at a home improvement store anyway?
So,
while the company website and marketing momentum has taken a step
forward, one thing that hasn't changed much are the turbines
themselves. Or their attitude to the "little guys" turbine market. We
get the drift that there isn't much time for us off grid people who
would be well served by an XL.1. Or at least something a bit smaller
than the behemoth Excel-R.
The XL.1 is a descent
product that would benefit from expansion but Bergey has expressed that
will not be the case. The availability of a 48 volt model, from which
many of us off-grid users could benefit, appears to be a phantom. As
early as 2005 it was listed as “In development, inquire about
availability”. This remark has now vanished from their 2010 website
update.
Instead of making a current favorite
into a more versatile machine, the company apparently has a 5 kW model
in the works. This may be an effort to compete in the 5 to 6 kW peak
power market currently dominated by Iskra, Kestrel and Proven. For
this, they should be applauded.
On the positive
side we always hear good things about the company's quick response to
problems. This feeling is common among owners and dealers/installers.
We have had similar experiences when asking for information. While
responses are usually not immediate, at least they do eventually
acknowledge our questions. This is not always the case with other
companies.
Combine the attention to their
existing customers with the 5 year (10 year for the Excel) warranty and
you should have at least a half a decade with little or no expense in
material and workmanship claims.
Though we
complain that their product line seems to be rather narrow and old,
they are a solid company that should not be brushed aside. Now we
wonder which company is going to join up with Home Depot.
Interestingly,
the XL.1 is only available in a 24 volt unit. In contrast, the SWWP
Whisper units have user adjustable voltages. As we have said
previously, there is no indication that any changes are coming down the
line. Unless you want to try the approach offered by Kansas Wind Power
(http://www.kansaswindpower.net/bergey_wind_generators.htm) for 48 volt
battery charging, there are no other options.
For
us, an area of technical concern is the rectification of AC to DC in
the nacelle. We are puzzled as to why they chose to make the rectifiers
somewhat inaccessible by having them at the top of the tower. The
Bergey people explained to us that they have tried several ways of
getting the power to the batteries and this one proved to work the
best. It still does little to ease our concern in this area. Our main
wind power generation comes in the winter. Typically the winter is cold
and dark and windy. This is not the ideal time to drop the tower just
to replace a part that could be located on the ground. We see this as a
point to be aware of.
There were early reports
relating to problems with the alternator. It seems that continuous high
winds would eventually cause it to fail. This was a problem with the
magnet wire vendor which has long since been resolved. Occasionally
this will pop up a reason to avoid the XL.1 but you can count it as
ancient history. It's sort of like a small wind urban legend.
The
XL.1 is a complete turbine/charge control unit for a reasonable price.
As with the trend among many turbine suppliers, there were some
substantial price increases in 2010. The XL.1 did not escape a price
markup. It is now pushing just over $3,000. Though it is not a
heavyweight machine by any means, it is reasonable for its size and
price. We still feel the XL.1 is a decent buy and would not object to
owning one.
Bergey's
flagship Excel is still going strong after 27 years. And if you live in
California, Hawaii or North Carolina you can pick one up at Lowes while
browsing for lumber, power tools or nails. Imagine turning the corner
of the light bulb aisle and running into that yellow nosed giant.
Unfortunately, if you didn't bring your deuce and a half flat bed truck
forget about toting one home and surprising your family.
Two
distinct versions are available. The Excel-S is the grid tie unit with
a rated output of 10 kW. The Excel-R is the battery charging version
with a rated output of 7.5 kW. Like their smaller XL.1, they use the
side furl governing method to keep rotor speed under control. We feel
that such a large machine swinging in and out of furl seems a little
harsh but evidently it works for the Excel.
The Excel
sends it current down the line exactly the opposite of the smaller
XL.1. While the XL.1 rectifies the current in the turbine nacelle, the
Excel runs three phase AC (wild AC or variable voltage) current down
the pole and to the charge controller before it is rectified to DC.
Here
is what we don't like. The wind speed at rated output is 27 mph. The
furling speed is 35 mph. It seems that furling at such a high speed
would cause unnecessary wear. Also, during a storm or high-wind period
the off grid system will quickly end up with a full battery bank and
the excess is burned off in some sort of diversion load. Though the hot
water or warm air is nice, we would settle for less energy output and a
longer turbine life.
On the other hand, if you are
grid tied there is an advantage to the energy harvest at high speeds
since you can continue to feed it into the ever accepting commercial
grid. While this sound really good, there have been problems reported
in some grid tie installations. When the Excel is operating for long
periods at peak output, the high voltage being produced is shutting
down the inverter. This can cause a loss of production at high wind
speeds.
The problem in this case is not the turbine
but rather the inverter. The occasionally troublesome GridTek 10
inverter has been replaced with the new Powersync II. So far the
Powersync II has been reported to not have the same problems. To keep
the power flowing down the line and into the grid should prove to be a
production boon in high wind locations.
Overall we see
the Excel as a solid performer. Weighing in at 1050 pounds, you do get
your moneys worth in metal. The Excel certainly has the service and
reliability history which should let you sleep well at night. On the
other hand if you want to live a little closer to the edge of
technology or design, Eoltec, Iskra, Proven and Ventera all have
turbines that approach or match the annual output of the Excel.
Photos Courtesy of DOE/NREL.
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