Axial Flux and Classic

[Menelos]

OK...if this was so, and assuming I connect a battery System of 80 Volts (forklift for example), I doubbling the start up voltage would be too much for the classic already...

As I read, it needs about 5 to 10 volts more than battery voltage. That would then be about 100 Volts....and at 150 Volts I would have to cut voltage already???

That would be useless for a wind turbine...even if I start at 3 m/s of wind...5m/s of wind would bne too much then already and the clipper would cut power...even with the classic 200 that would stil be a poor section to work with....alsways assuming this high battery voltage...for 12 or 24 Volts, this would be fine...at 12 volts I have a range of nearly 10 Times the startup voltage....so I am still confused until I can get a clear statement on that and not just a guess :-)

regards

MAx

[niel]

i don't work for midnight solar just to be clear on this and i'm not an expert with the classic although i have one for solar and i'm unfamiliar with wind apps, but there is a max when it comes to that battery voltage cushion and is i believe 48v and that's good for a 48v battery bank. if you have for example a 60v battery bank then the max cushion is still 48v. the classics are designed to operate with an input voltage at up to 150v for the classic 150, up to 200v for the classic 200, and up to 250v for the classic 250.

by the way, most controllers will require a few volts give or take above a battery voltage to operate, but it won't be 5-10v and mine has operated with the pv voltage drawn down to as far as 13.3v while mppting and the batteries were at 13.2v (in case you're wondering it wasn't in bulk charge). granted i wasn't outputting allot of current, but it does quite well with small voltage excursions from the battery voltage. extra voltage is good above a battery voltage for 2 reasons,
1> you have to account for slowdowns on a turbine or in my case lowered voltage from hot weather. this is usually not a factor, but it must be kept in mind that you'll want more voltage inputted to the classic than what the battery bank is and
2> higher voltages are morphed into more current on the output through mppt as long as you don't exceed the max operating voltage. there is a bit of lower efficiency with the wider differentials between input and output voltages, but sometimes people do it anyway to save on wire costs.

many of these things you can read in the manual that is for the classic and i don't feel like doing it for you so if my explanation isn't good for you then go read it for yourself. getting on me a bit because you don't know or don't understand is not going to get you very far, but here it is and you do with it as you see fit while biting your tongue, er finger.

[Halfcrazy]

OK...if this was so, and assuming I connect a battery System of 80 Volts (forklift for example), I doubbling the start up voltage would be too much for the classic already...

As I read, it needs about 5 to 10 volts more than battery voltage. That would then be about 100 Volts....and at 150 Volts I would have to cut voltage already???

That would be useless for a wind turbine...even if I start at 3 m/s of wind...5m/s of wind would bne too much then already and the clipper would cut power...even with the classic 200 that would stil be a poor section to work with....alsways assuming this high battery voltage...for 12 or 24 Volts, this would be fine...at 12 volts I have a range of nearly 10 Times the startup voltage....so I am still confused until I can get a clear statement on that and not just a guess :-)

regards

MAx

If you are truly charging an 80vdc battery? that is an odd voltage but if you truly are then you will need the 250KS it is designed for up to 120vdc battery's. Our other 3 controllers are designed for up to a 72 volt battery. The Classics operate to the voltage that is in there model number like the Classic 150. This model will run up to 150 volts input. if it exceeds150vdc it goes into HyperVOC which is the area above operating voltage based on the nominal battery bank voltage up to 48v. The Classic will not produce power in this area it will be in HyperVOC mode.

Basically a standard wind turbine will be designed to cut in at a desired wind speed with a voltage that is say 5vdc higher than battery voltage. Most turbines will run up to 2 times that number happily some can go to 3 times that number the real limit is how you view the turbines behavior at those higher speeds. The Clipper will simply "Clip" any excess voltage above the set point you program it for.

[niel]

menlos,
sorry about missing where you mentioned about an 80v battery bank as i would have then referred you to the 4th classic available and thought you were only interested in the input voltages. i guess i deserved a bit of guff from you for my oversight. my apologies.

[Menelos]

Thanks fpr your answears first of all...

I did not yet make up my mind about which battery bank voltage I will choose. Those 80 Volts was just en example to make my point clear.

So basically the lower the Voltage of the battery bank, the bigger is my window of Voltage butbthe smaller will be the output power that can be achieved as maximum current is a fixed value...understood! :-)

I have read the manuals by the way....but the web page is some kind of confusing...there is something everywhere...and no all things match...sometimes you find old information and then again something that was changed already and does not apply anymore....so somewhere I read about this 150V plus battery voltage as maximum voltage...this is why I was asking in the first place...but thats sorted nor, Thanks :-)

[kitestrings]

Hi Max,

Ryan's covered most of it, and has probably the most experience with using the Classic for wind.  We've just purchased 2-250's, but it will be some time before where opperational/

With the axials and MPPT you'll have rotor speed tracking directly with wind speed. My understanding is (if your willing to live with these speeds) you'll could see 4 or 5 times cut-in volts at full power at furling point.  This sounds scary and most folks seem to be living with something less than that.

Perhaps equally important, if you should loose load you can expect about an ~80% overspeed - at best furling protects the machine.  The voltage rises proportionally, and this is where the Clipper can save the electronics.

We've had some success with load diversion - Edward also has on this board (perhaps he'll chime in) - but you really need a fail-safe.

Regarding battery voltage.  I would definitely not recommend 80 volts, or 120V or any non-standard nominal bank voltage for that matter.  I think the hassles will be many.  We have 48V now, but this was an upgrade from a 12V original system.  We still have lots of 12V lights from the original design run off a 12V 'tap' with a voltage equalizer, and even a couple of 24V devices.  If I had it to do again I'd avoid it.

Best of luck with it, and do keep us posted.

~kitestrings