Navitron Wind Generator Performance Data

[filipinobrian]

I was wondering if the performance graphs on the website reflected 'off load' or 'on load' output. If it is off load what can be realistically expected when charging batteries?

Brian

[Ian]

Brian - the graphs are on-load.

They should be real observed results rather than theoretical. By the looks of the curves, they are almost certainly observed results into an "ideal" resistive load. Note that the load applied in normal use may be very different to the load that was used to measure the power output of the wind generators for the graphs as the manufacturer will want to show off his products in the very best light.

Recognise that turbine output charts are reflecting absolute optimum conditions which includes measurement in a wind chamber with laminar airflow, and resistive loads designed to give the best curves. It is very, very unlikely that you would see these power outputs in normal use.

A battery bank is a very easy load for a wind generator as it has an inherent voltage (even when discharged) which means that the generator can spin before the batteries accept a charge current. Once the generator is spinning enough to overcome the natural voltage of the batteries, the batteries will accept just about any power that the generator can provide. This is good for the generator but care should be exercised in the sizing of the battery bank not to exceed the charge currents of the batteries or their lives will be shortened.

I hope this helps.

Regards,
Ian

[filipinobrian]

Thanks for the info Ian, The only reason for the question was that the power outputs seem amazing compared to their price! I research quite extensively into another genny, (a 400watt model prodced by an American Company) & after a while I found a true performance curve produced by an indipendent source illustrating that the 400watt figure claimed could almost never be acheived in practise.

Brian

[PEMTEK]

I have a 500w and a 1kw turbine from the same manufacturer as Ivan's turbines. I would say under some conditions the graphs supplied are conservative as the peak output from my turbines are similar to the peak values Ivan states in the basic specification list and not in the graphs. I have seen 36Amps from my 500w 24v turbine in stronger winds! Even on days when there seems to be just a light breeze i see around 1:5 of the rated output
minimum.
 
The only problem I have encountered was that one of the guy wire adjusters worked itself loose and the 500w generator tower fell leaving a rather large hole in my garden and a broken blade! (15+vat  ) Now I have fitted lock nuts on the guy wire adjusters!

I am working on my own synchronizing inverter design at the moment to connect these things up to my house without requiring batteries I will post how I go on.

Phil

[filipinobrian]

Thanks for the re-assurance Phil, it seems I can count on a valuable contribution to my energy needs from 2 x 200 watt turbines 
Brian

[Ivan]

I think many manufacturers provide quite unrealistic claims for what their turbines can produce.

I believe that turbines should be realistically able to produce the power claimed - so all of our turbines are rated at relatively low wind speeds - and the graphs are produced from real-life measurements rather than theoretical measurements that can be 'fiddled' to make things appear better than they are. As a result, our turbines will all produce considerably more than their rated power (often 50% more) in higher wind speeds.

Two of our customers have compared the performance of the Navitron 500W turbine with a well-known scottish 2.5kW turbine. To their surprise, in almost all wind conditions (with the exception of extremely windy weather...which accounts for less than 1% of the time), the Navitron 500W turbine outperformed its much larger competitor!

Ivan