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.
Our Point of View
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.
- Relatively low rpm
- Furling* (In our opinion furling is justified by the price)
- Currently only 24 volt model available
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.
- Proven Reliability
- Furling* (In our opinion furling is justified by the price)
- High furling speed