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12V 1200W DC Wind connecting to Fronius Solar Inverter.

glenkleidon

New Member
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Sep 18, 2021
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27
Hey All,
I came up with this solution - It may be entirely crap - please let me know where the problems are!

At one end Chinese brand 1.2kW 12V Vertical wind generator (supposedly) with suitable charge controller. (IE that is 100A max current theoretical!) Given that the whole unit was under $500 - I cant see that charge controller being adequate. Wind Generator Info

At the other End I want to connect this to one of the spare DC input lines of either my Fronius 4.0.1 Or Fronius Gen 24 - 6. The Input specs, the 4.01 requires 80V min, but Gen 24 will accept 65V DC, both up to 1000V. Max Cutoff Amps is 27 on the Fronius, so the trick will be keeping the peak voltage down to around 20A.

So the solution is basically this:
Wind turbine -> charge controller -> Intermediate storage 12V Deep Cycle battery -> DC-DC-boost controller (12V-->80V) -> Current protection -> Fronius DC Input.

The key is the booster converting the 12V DC to 80VDC acceptable to the Fronius input line, the trouble is controlling the input current. I cant see that the fronius would care how the DC is generated - it would normally be PV - but why would it care that it was any 80V input source?

Is this solution even close to viable?
 
Initially thoughts are that the terminal connections will probably need to ensure that the charge controller cant direct feed to the Booster. - would a physical barrier do the job? IE Charge controller wired direct to terminal and using a slightly higher resistance metal or a physical hole punched in the connector to force a long path for the outgoing leads?
 
BTW - I would of course be much simpler to add a suitable Micro inverter. 2 reasons: 1) I am limited to 10kW of inverters by the grid supplier (ie adding a new micro inverter would tip over the limit. 2) I have a 16kWh of BYD HVM battery bank. The Fronius should automatically pipe the incoming wind power to the house and to the battery bank at night assuming there is wind. The 12V battery will be serving really as the current limiter and would be discharging as fast as it is charging. So theoretically it wont ever trip high voltage cutoff - although it would likely live at a low charge state during the night. Hang on - think I just found a problem.- hmm - need a low voltage cutoff between the battery and the fronius....
 
Before spending money on a wind turbine do a bunch of reading, very few produce nearly as much as the dreamer strike that the designer dreamed that it could produce.....seriously Ive seen far too many that spun and produced diddly squat. Real power is non existent below 15-20 m.p.h. constant wind speed, many need 30 m.p.h. to achieve rated power, How many hours at that speed do you have? There are tables online that spell out wind data for very numerous locations, all wind farms correlate this data along with hundreds of weather services. I have a Symphonie 23 channel digital data collection system that has several anemometers a wind direction vane and never see sustainable wind for wind power. Yes i have tinkered in it......solar is far better,cheaper,and far more reliable
 
Thanks @Tecnodave e. Yes, Solar is awesome - except at night. I already bought the generator - more for fun than anything. So - your point is accepted.

This exercise however is about assuming: a) you did have a wind generator (producing diddly squat or in a gale the rated output), Or b) (say) a hydro generator (which probably would be 3 phase 48 v though...), WOULD this setup work?

I am expecting quite poor results actually there are at least points along the path for considerable losses - but all I want it to do is work without blowing up the Fronius - I dont really mind how well it works to be honest.
 
BTW - I would of course be much simpler to add a suitable Micro inverter. 2 reasons: 1) I am limited to 10kW of inverters by the grid supplier (ie adding a new micro inverter would tip over the limit. 2) I have a 16kWh of BYD HVM battery bank. The Fronius should automatically pipe the incoming wind power to the house and to the battery bank at night assuming there is wind. The 12V battery will be serving really as the current limiter and would be discharging as fast as it is charging. So theoretically it wont ever trip high voltage cutoff - although it would likely live at a low charge state during the night. Hang on - think I just found a problem.- hmm - need a low voltage cutoff between the battery and the fronius....
fixed - added undervolt protection contoller between battery and booster.
 
I built a 3 blade wind generator using variable speed motor DC motor with series and shunt field coils, rated 3/4 hp from 60 r.p.m. to 1800 r.p.m. thats 3/4 h.p. at 60 r.p.m. , not derated by speed....240 lbs. gilmer notched tooth belt with machined pulleys 5:1 gear up , pretty hi tech, electronic controls manipulating the generators 16 to 1 speed ratio down to wind speed ratio of 9 to 1
3500 watts at 23 m.p.h. laminated sitka spruce blades.......carved on duplicating lathe.....2 year project...
I had a place on a ridge with a good wind funnel from the ocean.....
 
I built a 3 blade wind generator using variable speed motor DC motor with series and shunt field coils, rated 3/4 hp from 60 r.p.m. to 1800 r.p.m. thats 3/4 h.p. at 60 r.p.m. , not derated by speed....240 lbs. gilmer notched tooth belt with machined pulleys 5:1 gear up , pretty hi tech, electronic controls manipulating the generators 16 to 1 speed ratio down to wind speed ratio of 9 to 1
3500 watts at 23 m.p.h. laminated sitka spruce blades.......carved on duplicating lathe.....2 year project...
I had a place on a ridge with a good wind funnel from the ocean.....
Sounds awesome - I clearly have a long way to go to get to that level of dedication!
 
i have been tinkering since i was a pre teen in the backwoods of Alaska, still havent done enough 55 years later, did a career in engineering, just getting into bigger lithium batteries

If I stop learning I will die...
 
There are probably voltage efficiency curves for the fronius inverter, maybe available from fronius . You need to boost the dc voltage to a higher voltage than the AC voltage peak to peak value which is 1.414 times the peak value of the AC line......120 volts AC is 120 volts positive then 120 volts negative for a peak to peak value of 240 volts then 1.414 times that approximately 356 volts for best efficiency. Running that type of inverter at that low of DC voltage will result in poor effeciency.
But doing it is now you learn.
 
There are probably voltage efficiency curves for the fronius inverter, maybe available from fronius . You need to boost the dc voltage to a higher voltage than the AC voltage peak to peak value which is 1.414 times the peak value of the AC line......120 volts AC is 120 volts positive then 120 volts negative for a peak to peak value of 240 volts then 1.414 times that approximately 356 volts for best efficiency. Running that type of inverter at that low of DC voltage will result in poor effeciency.
But doing it is now you learn.
Thanks for this - yes, I see the higher the stepped up voltage the higher the efficiency. The largest boost converter I could find was 12V to 80V - 20A, which is just enough for the Fronius to accept. If I could find a DC-DC Converter that can produce a higher Voltage step up with 20-30A I would be happy to use it. Can anyone recommend a device?
 
Thanks for this - yes, I see the higher the stepped up voltage the higher the efficiency. The largest boost converter I could find was 12V to 80V - 20A, which is just enough for the Fronius to accept. If I could find a DC-DC Converter that can produce a higher Voltage step up with 20-30A I would be happy to use it. Can anyone recommend a device?
I found a 90V one here but price is starting to head up And another one that apparently goes to 97V - but appears to be the same as the other 90.. So the 80V one looks like it will do for experimental purposes. So again though - so long as it works, the efficiency is not going to matter too much at this point - As I said it is likely to be poor in any case. Still - if anyone can spot a device that can go from 12 to 250 that would be great. But the question is then, is the losses due to the booster more or less than the losses in the Fronius? The Boosters mostly are around 95%. The efficiency curve for the Fronius from a paper I found is probably going to be around 90% - so it might not matter that much.
 
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If you ever do this please let me know what the results are, i'm curious. I suspect the MPPT of the inverter won't play nice with a voltage source DC-DC converter.
 
I have had advice from Fronius about this: essentially they are fine with the idea but are concerned about the efficiency.. It biggest limiting factor is ensuring that there is a spare input line so that you can configure the MPPT to expect the constant voltage that the booster will deliver. They freely gave the instructions for changing the settings via the Inverter's web interface.

Currently I have a booster that can deliver around 90V at 1500W. But the actual output will depend on the battery capacity. I am still waiting for my 400Ah LiFePO4 to arrive but I will probably set the output power to around 500 to 700W. The efficiency curve on the Fronius is not that great at that voltage, but remember - this is free wind energy that we are currently getting 0W, so anything greater than 0 is a win.
 
I found a 90V one here but price is starting to head up And another one that apparently goes to 97V - but appears to be the same as the other 90.. So the 80V one looks like it will do for experimental purposes. So again though - so long as it works, the efficiency is not going to matter too much at this point - As I said it is likely to be poor in any case. Still - if anyone can spot a device that can go from 12 to 250 that would be great. But the question is then, is the losses due to the booster more or less than the losses in the Fronius? The Boosters mostly are around 95%. The efficiency curve for the Fronius from a paper I found is probably going to be around 90% - so it might not matter that much.
I just received 5 x 90+V boosters from a seller in china at $12USD each. They were all exactly the same, well laid out and beautifully built with quality connectors and excellent soldering. I also received the 97 version as well which I bought to compare. Again well assembled and the inductor coil does indeed appear to have slightly greater capacity - so likely all as advertised but at 5 times the cost.
 
I just uploaded this youtube video https://www.youtube.com/playlist?list=PL42y13vA83asowyQdm_LIxH8NmlErr2w0

My new battery system is being fitted tomorrow, so I will be making sure they configure the second PV input for constant voltage.
Hello
Interested in how you succed to feed in DC power on a PV-string on Fronius inverter, from a windturbine. I want to do myself

I have not read all details in conversation but the windturbine I see in your setup in beginning is probably wrong specified. Power in the wind at 12m/s is about (1,3x 12 x 12) / 2 = 94W per 1square meter area size of used turbine is about half of that also theoretical max 45W I think efficincy for that type is about 30% so at 12m/s I should expect 10-15W power if 12V about 1A
 
My wind turbine turned out to be a dud, but the temporary storage worked out great. I can feed the batteries by wind (but I dont have a working generator at the moment), solar or on-grid battery charger using "excess solar". I have a YouTube playlist here

The specific video where I turned it all on is
 
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