I'm still not 100% sure which of the 3 Classic models would be best for my wind turbine. I've got a "2kW" wind turbine, but I've seen brief surges up to 3.5kW during strong wind gusts. Most I've seen on the ammeter is 65A. This is for a 48V battery system. I would expect the Classic MPPT to boost the power curve even further, but I do not think it will get past 3.5kW very much. I'd expect the Classic to fatten up the power curve at lower than peak power.
I would prefer to have the biggest voltage ceiling possible, but I don't think the Classic 250 would be able to handle the current of my wind turbine. I am thinking that Classic 200 might be better, but maybe I'd need the higher current capacity of the 150. But, then I lose some of the higher voltage advantage of the Classic.
What do you Midnite folks recommend here?
Edward
I am leaning towards the 200 for most turbines as it gives you the balance between voltage to play with and current capability
It is difficult to tell which Classic is best suited for your turbine. It really comes down to free wheeling output voltage. If the turbine is going to exceed our HyperVOC voltage when the batteries are charged, then it is very possible that the Classic will turn into a gooey pile of mush. This condition is pretty hard to cover under warranty. There are voltage limiters available fron DC-Power, but are at a fixed voltage that will work with the 150 Classic. Ryan's Clipper is adjustable and is a good plan for the time being. We are in development of two different voltage limiters (Clippers). They won't be ready for about 6 months though.
Choose your Classic based on what the output voltage is going to be. IT is extremely important to control the voltage coming into the Classic!
OK. Thanks for the feedback, Ryan and Robin.
Let's say I have a Classic 200 with a voltage clamp to make sure voltage into the Classic never exceeds Hyper VOC. What would you say would be the highest current carrying capacity? How many amps can the Classic 200 handle with a 48V system?
Edward
here you go
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Thanks Ryan. That's exactly what I wanted.
On that chart, the maximum PV input voltage on the Classic 200 is listed as 315V. Is that a typo? That's the same as the Classic 250.
Edward
Looking at the Absolute Current Output, I see the following power handling capability:
Classic 150 (83a x 48v): 3984W
Classic 200 (65a x 48v): 3120W
Classic 250 (55a x 48v): 2640W
Can you explain why the power handling ability is so much less on the higher voltage Classics?
Could you also explain what will happen if the Absolute Current Output rating is exceeded?
I remember boB or Robin saying that the Classic will continue to try to operate as long as temperatures are not too high. I would have the Classic mounted in an air conditioned room and have it fully vented, so maybe I could get away with slightly higher currents.
I keep thinking about how the Classic will work with my HY-2000 wind turbine. It almost looks like I'd need to choose the Classic 150 (or 2 Classics 200's or 250's) to have the current carry capacity for this wind turbine. Usually peak power during high winds is 60A. I've seen 65A surges for a couple seconds before. I think that's about the upper limit of what this turbine can produce while being clamped to the 48V battery bank. I'd estimate that the Classic might boost peak power a little but probably no more than 25%. Even so, that would put peak power output right around 80A. That means I'd need the Classic 150 to be able to handle that current. Then, I think the voltage clamp necessary to protect the Classic might really kill the wind turbines power output. This HY-2000 wind turbine makes peak power around 650 RPM. Having to run with 2 Classics could get expensive. Still trying to figure out if this is going to work with my wind turbine.
Edward
The Classic does have limited surge power available. Beta units had unlimited surge power and the results were spectacular. I do not know what boB has done to production units to reduce the unlimited surge capability. We do plan on keeping this feature in some form or another, but we also need to make sure it doesn't affect reliability. The Classic controlls the output voltage of the turbine. When output power reaches the max continuous point, the Classic has no choice but to allow the turbine output to increase. When the voltage increases higher than what is should be for maximum output power, the output power goes down. Depending on how hard the wind is blowing and how full the battery bank is, the voltage may rise to the maximum input voltage. On a Classic250, this would be 250 volts DC. The Classic will shut off when it reaches this voltage. The Classic will then be in Hyper VOC mode to protect against the impending higher voltage that is sure to come. Since the Classic is turned off, the turbine will free wheel. The output voltage of an unloaded turbine spinning fast is different for each turbine model. This condition is dangerous. Tod at Bergey designed the 48V XL.1 to run below 250 volts in this condition. We do not know where any other turbine will end up. This is why we are designing two different Clippers (voltage limiters). You can always use Ryan's trick to stack two Classics if power is going to be too great. We have lots to learn as customers hook up the different turbines available. Sometimes the results will not be a plesant experience since the Clipper is not yet available. That is not an excuse to just let her rip though. Replacing blown up Classics from over voltage is expensive. I'm sure we will make special cases at first since we are in uncharted territory, but keep in mind that an over voltage condition is very dangerous for the Classic. That said, we have had many over voltage events during our beta testing with only one melt down. There was nothing salvageable after that event with a 17 foot otherpower turbine. Two Classics solved the problem and it is now happy putting out 9000 watts.
Robin thanks for the info on the other power 17 footer would have like to see halfcrazy beta unit melted puddel haha what about the use of stacked classics and one being set to (140volts) for aux relay say to a 3phase transformer dump load to water heater or second battery bank and the secound classic (148volts) like ryans (halfcrazy) crowbar relay will see first will take baby steps on set points and amps will get some more info and drawing when hooked up also could reverse the set up for amps too have a happy new year !!!!!! cheers Mike
I will let Halfcrazy step in on the alternate dump loads, but I think I understand what you are suggesting. The dump loads don't do any good at all when connected to the output of the controller. That is how present day battery regulation is done. We need to stop the turbine from putting out too much voltage. This dump load must be connected to the turbine side of things. The Classic input must be isolated from the dump load by a rectifier or some similar gizmp. If you short out the input of the Classic(or any other controller0, it will go up in smoke. I do not know how to insert a picture here yet, but Ryan can show you a picture of his handy work with the melted down Classic. We really don't want to see this happening.
thanks Robin for the info and yes will isolate the classic input with rectifiers have some good photos of stator burn outs but have not lost a magnet yet will get with Ryan before I thorough the switch and make drawing for it like his homemade diversion load relay pdf file Happy New year sub zero temps here in Rochester just board cabin feaver will be waiting for spring and getting to work on the new equipment cheers Mike
Ok did some one ask for a picture of one of my record setting smoke shows ;D
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Thanks for the picture Ryan. Now I can see what you meant when you replied to my other Classic Cooling post. Loooks like the 8 MOSFETs heat sink on the die cast aluminum case along the right side. There are ribs on the outside of the case and the "turbo" fan blow across those ribs/fins.
Was that a Classic 150, 200, or 250?
That 17' turbine put out 9kW peak, didn't it?
That's a LOT of power to run through one Classic!
- Edward
I can understand that the current capacity of each of the Classic versions (150, 200, 250) is a function of the power that needs to be handled (and resulting heat dissapated). So, the higher voltage capacity of the Classic 250 means that it can handle less current (P=IV).
What my brain keeps coming back to is whether a Classic 250 that is run at a lower voltage limit would be able to handle more current than the specs show (Classic 250 = 58A max @ 48V)?
For example, lets say I buy a Classic 250 and then discover that my HY-2000 turbine runs at a voltage of 190V at peak power output. If I use Ryan's homemade Clipper idea and maybe tweak the idea a little using a Crydom 3 phase SSR, and keep the voltage clamp set to 200V. With the lower voltage, then I am assuming that the current capacity of the Classic would go up because the total power handled (and heat dissipated) would be less.
In that situation, would a Classic 250 have the current carrying capability of a Classic 200?
I suspect not exactly, because of the different components on the board for the higher voltage capability. But, I wonder if it would be close. You might be seeing where my thinking is going with this. Choose the higher voltage Classic since I am not sure of what the voltage will be on my particular turbine, and run it at a lower voltage level to get additional current capacity.
Edward
That is a tough one to explain fully. the higher voltage units do handle less current for a couple reasons as you stated. The true issue is the current limit setting from the factory obviously if we made the 250 say adjustable up to 90 amps people would hook up 90 amps of solar panels and cook it. Now the tricky part wind is usually not steady so say you where running a steady 35-40 amps but a quick gust hits it and it would like to spike to say 80 amps for a second or 2. I think we need to have some sort of surge capability above max amperage setting but only in wind mode? I have chatted with boB about this and it may be something he works out at some point. The Classic would run until it sensed it was getting warm than back its current limit down a touch. Like I said it is a slippery slope.
Quote from: keyturbocars on January 03, 2011, 11:44:38 AM
Thanks for the picture Ryan. Now I can see what you meant when you replied to my other Classic Cooling post. Loooks like the 8 MOSFETs heat sink on the die cast aluminum case along the right side. There are ribs on the outside of the case and the "turbo" fan blow across those ribs/fins.
Was that a Classic 150, 200, or 250?
That 17' turbine put out 9kW peak, didn't it?
That's a LOT of power to run through one Classic!
- Edward
This was the second Alpha unit to ever go out of MidNite it was a 150 volt unit that I had routinely fed to much voltage. It was tough as a bag of nails the issue was it hit the current limit of 99 amps and the voltage spiked to around 375vdc Over voltage issues are pretty dramatic there will be no hiding the fact the Classic was over voltaged. This is exactly why the clipper is needed.
Makes sense Ryan. I agree that a higher surge rating in wind mode would be a good idea. I've seen my HY-2000 turbine putting out 45 amps fairly steady and then for maybe 1 second surge to 65A in a strong wind gust. The analog ammeter sweeps up to 65A and as soon as it gets there, it starts to drop back down to 40's. Very intermittent and not sustained.
Quote from: Halfcrazy on January 03, 2011, 12:33:39 PM
That is a tough one to explain fully. the higher voltage units do handle less current for a couple reasons as you stated. The true issue is the current limit setting from the factory obviously if we made the 250 say adjustable up to 90 amps people would hook up 90 amps of solar panels and cook it. Now the tricky part wind is usually not steady so say you where running a steady 35-40 amps but a quick gust hits it and it would like to spike to say 80 amps for a second or 2. I think we need to have some sort of surge capability above max amperage setting but only in wind mode? I have chatted with boB about this and it may be something he works out at some point. The Classic would run until it sensed it was getting warm than back its current limit down a touch. Like I said it is a slippery slope.
You won't be able to adjust the current limit on a Classic 250 to 90 Amps...
As far as surge for wind, this is something that, if implemented, will be able to be turned off (disabled).
That is so if one is using the current limit because they are using a smaller breaker size, it will be able
to trip. The amount of surge will be limited too, of course, but will also be dependent on temperatures.
boB
nice burn out looks like my turbine when I put a 12 foot dim blade on a 10 foot turbine gen turned out to be a 2in hand #18 wire burner rat nester haha tail was tangled up too HAHA DID NOT LOSE ANY MAGNETS THOUGH METAL MAGNET HOLDER WORKED CHEERS Mike maybe have to get a different topice for burn outs? enjoy
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Quote from: Halfcrazy on January 03, 2011, 12:37:07 PM
This was the second Alpha unit to ever go out of MidNite it was a 150 volt unit that I had routinely fed to much voltage. It was tough as a bag of nails the issue was it hit the current limit of 99 amps and the voltage spiked to around 375vdc Over voltage issues are pretty dramatic there will be no hiding the fact the Classic was over voltaged. This is exactly why the clipper is needed.
Ryan, So if you had your homemade Clipper (voltage clamp) attached to that Classic, do you think it'd still be alive today?
Quote from: boB on January 03, 2011, 01:54:56 PM
You won't be able to adjust the current limit on a Classic 250 to 90 Amps...
As far as surge for wind, this is something that, if implemented, will be able to be turned off (disabled).
That is so if one is using the current limit because they are using a smaller breaker size, it will be able
to trip. The amount of surge will be limited too, of course, but will also be dependent on temperatures.
boB
boB, I was studying the power curves of the different Classics. In the current production run of Classics, are these the current limits programmed in the firmware of the Classic?
Classic 150 = 83A @ 48V
Classic 200 = 65A @ 48V
Classic 250 = 55A @ 48V
If not, then what are the current limits programmed for 48V?
I confess that I am itching to try a Classic out, but I realize that I might need to step back and let the beta testers pave the way a little further before I can move forward.
Thanks,
Edward
Surge power is something that we have been experimenting with. We need more units in the field before we can determine just how much surge to allow. To answer your question regarding higher current at lower voltages: the answer is yes and no!. Yes, you definately get more power as the MPPT voltage is lowered. Take a look at the power graphs on our home page. You will see that the output power ratings of the Classic 250 were already based on 180 and 200 volts MPPT. You do not run a 250V unit at 250 volts. This is because of VOC vs. MPP of a solar panel. Maximum power is typically 75 to 80% of VOC. The 250 volt limit is to allow for VOC, but is not intended to run continuously at that voltage. May I suggest you find out what your free wheel voltage is going to be in high wind?
Robin,
The freewheeling voltage on this HY-2000 turbine is something that I would really like to determine (safely). The controller that comes with the HY-2000 is fairly simple, but to it's credit it does have a safety feature built in. It has a set of relays that are energized during normal operation and allow the turbine to run normally. If the connection to the battery is somehow disconnected (which would result in a freewheeling condition), then the relays de-energize and the turbine brake is automatically applied. Smart idea.
I know I could bypass the HY-2000 controller altogether and set up a rectifier directly to the battery bank with a breaker. Then I could wait until the wind is roaring and disconnect the battery and measure peak freewheeling voltage. After my first wind turbine failed (different brand), I am very hesitant to try this. The other turbine failed when I went to shut it down in 30mph winds. Having that other wind turbine ROARING for 1 hour as it freewheeled with a burned out stator was something that I never care to repeat! Perhaps this HY-2000 would never do this, but I am very hesitant. It's a gamble that could cost me a LOT if I am wrong and also do damage to my home. My concern would be that at freewheeling RPM, the voltage will be high and then abruptly reconnecting the output to the battery (or trying to abruptly brake the turbine) could result in a spike that might burn out stator windings. Then I have another runaway turbine that is ruined. Maybe not.
Does anyone have any suggestions for the best way to determine max voltage of a turbine?
I suspect that it's just by letting it rip in a freewheeling state and see what happens. I confess that I'm a bit of chicken in this regard. My wind turbine is close enough to my house that a thrown blade could be trouble. On the last turbine, I had my wife and 7 kids hunkered down in the basement while I was running about the farm dealing with other problems during that wind storm. There was nothing I could do about the runaway turbine. Like I said, I don't want to repeat that scenario again.
I've asked the HY Energy factory the question about max voltage, but they did not seem to understand this. They replied back "about 60 volts" which is the max battery voltage that the HY-2000 controller allows. Again, to their credit, they have supplied me with detailed data that I think many other wind turbines companies could not even supply the consumer. I could try to ask them again and see if I can explain it better. There is a bit of a language barrier, but the person I've been dealing with has been very helpful and quite good with their English.
All that to say, if someone knows of a safer way to determine max voltage, then I'd appreciate the suggestion!
Edward
try asking them what the maximum unregulated voltage output of the turbine is so you don't have to disconnect the controller and let it freespin without the load of the batteries on it to find out yourself.
I just wrote another message to my contact at the HY Energy factory, and I am hoping that this time I did a better job of describing what I want to know. They have done extensive testing and they have the data to back it up, and I am hoping that they will be able to tell me the open circuit voltage (Voc) of the HY-2000 turbine in high winds.
Edward
I checked my e-mail this morning and I received another reply from HY Energy. The provided me with exactly the data that I requested. Time and time again, I've been impressed with how professional they have been. They are a gem among some of the less honorable companies cranking out wind turbines in China and elsewhere. I am glad that I have a HY-2000 wind turbine. They have rated it very conservatively (a "2kW" peaks at nearly 3.5kW). Quality (fit and finish) on turbine itself was outstanding. It was reasonably priced. They have done extensive research and then testing before releasing the HY-2000. Impressive!
I was very excited to see the data... OK, I'm a bit of a nerdy mechanical engineering type! :) It looks like a Classic 150 will be a great match for this turbine. As long as there would be some room for surges, I think the Classic 150 would be great even under the highest winds & power output of the HY-2000. In the past, I asked them what is the safest maximum RPM for the HY-2000. They told me 800 RPM. That corresponds to 134vdc. I would set the voltage clamp (similar to Ryan's except with a Crydom SSR) to max of around 125Vdc to keep turbine RPM's safe and also keep the Classic 150 safe. By the way, rated power output of 2000w occurs at 534 RPM where it puts out 42A @ 48V according to some other data HY Energy provided me.
(http://www.key-ideas.com/HY-2000-Voc.jpg)
Midnite guys, let me know if I am interpreting this data correctly in regards to the Classic 150.
Edward