High voltage/low amps vs low voltage/high amps

[makenzie71]

I'm looking at a 4kw rated turbine that is offered in "on grid" and "off grid" versions and I'd like to get you guys thoughts on the matter.

The on grid version runs at 350~450v and 10~15 amps.  The off grid version is a 48v turbine that can peak upward of 125 amps.  Both would have about 125~150ft of cable to run.

My setup dumps everything into the grid.  I would have to triple my current capacity to expand to be able to manage adding a 4kw turbine, but it's known territory that, while it could be better, does what I need it to do.  I'm currently leaning toward doing this but, again, it's because it's known territory and because if I strike it rich I can buy enough batteries to actually disconnect from the grid haha.  I must admit I'm not eager to deal with 100 amp wiring.

The on grid version has the appeal of running at low amperage and I like that, but I'll have to find an inverter than can deal with it or find a way to reliably bring the voltage down to where I can tie it into a 48v system.  I've tried a couple of MPPT controllers in the past to bring 60vdc+ down to a 24v bank and had terrible luck getting them to work with wind turbines and I'm not sure I'll have any better luck in this situation.  The few "wind turbine" inverters I've seen that I felt could reliably handle this turbine have been extremely expensive, but there's a chance I could run it into a string inverter and it'd work passably.

What would you guys suggest?

[Mary B]

What brand? Link?

[makenzie71]

It’s an ista breeze heli 4.0

[Mary B]

With grid tie and that long of a wire run I would go high voltage...

I see you have had 2 other of this brand? How do they hold up?  I see rather high winds in winter... I can have 3-4 days in a row gusting to 60-70mph! In summer 90+ once a summer usually from a down burst or derecho(or a tornado near miss like in 2008... F1 tornado hit the grain elevator, tore the top 20 feet off and dropped it in the intersection a block away. Intact! They tore off the 2 feet of damaged boards and craned it back up and on! It lifted and went over my house before touching down again 1/2 mile later).

Cold weather performance too, I see -28f in winter most years, -31f is the record low...

[makenzie71]

I've had half a dozen of their turbines and currently still have an i500, i2000, and a Heli 2.0 up in the air.  I had an i1500 for a couple years, only pulled it down to replace it with the 48v i2000.  I believe the i1500 and i2000 are easily the most watt/dollar you can in a consumer turbine and the only DIY turbines with similar output I've seen that cost less to build were Hugh Piggot style axial turbines.  I'm not quite so impressed with their smaller body turbines like the i500, they work but they need a lot of very steady wind to really build up any power.  I've had the Heli 2.0 up for a year and a half or so and it's been a monster.  I think the i2000 is a slightly better watt/dollar ratio but the Heli makes about twice the power in the same wind.

My i1500 I spent the first year being very mean to.  There was one storm that the wind spooled it up to over 3000w, blew up one of my batteries, then free-wheeled the rest of the night.  After getting the battery bank set back up it spent the rest of its time with me running just as nice as ever.

We don't get as cold here and, honestly, seldom gets below zero, and usually if it's that cold it means there's no wind...I can't really say how well they perform in the extreme cold but I can't see any reason they'd have problems.  I've had them running in freezing weather, though, with rain and snow and hail, as well as all summer in 105+ heat and sticks and dirt flying, and the only failures I've had are these silly connectors they like to use to connect the stators to the slip rings.

I will say my goal has been to see when and how they break, I always recommend that if you see a heavy storm coming that you shut them down rather than risk the blades or stators.  I f someone is looking to buy a turbine, though, I always recommend the i1500 or i2000.

[SparWeb]

I looked up the Istabreeze website.
It didn't take long for the BS meter's needle to rise into the red.


Do the math:  Exaggerated claims.
Diameter is 3 meters.  Betz Limit is 59%.  No machine can match Betz limit through the entire power curve.  Extraordinary claims require extraordinary proof. 

Wind speed_____claim____max possible__judgement
5 m/s                 300 W          300 W        = probably BS
7 m/s                1000 W         840 W        = BS
9 m/s                2000 W       1800 W        = BS
11 m/s              3800 W       3300 W        = BS

So I'm surprised you still give your money to this outfit.

Anyway...

Whatever you get from that thing, decide for yourself if you are ready to and equipped to handle 400 Volts DC safely.  That's a wholly different kind of death than being electrocuted by AC.

There are some screwy specs on the charge controller.  I think it draws a standby load of 300 W out of the batteries, constantly.  They say that you need a 300W PV panel, which I assume is to compensate. Or play with the day/night numbers to say that the 300W PV in the day compensates for 150W drain all day.  Either way that's a huge drain.

[makenzie71]

Look I really do love iSta Breeze but their specs and graphs are rubbish lol.  If you want to go for a real ride check out their specs for the Heli 4.0

https://www.altinelenerji.net/Technical_Specifications_Heli4.pdf

And then take at their specs for...again...the Heli 4.0 lol

https://www.altinelenerji.net/heli-4-0-ongrid-wind-turbine

For a real adventure take a shot for ever contradictory piece of information you see

I've been playing with...and by playing with I mean really abusing...their turbines for three years now it is generally been pretty decent and reliable.  I have had failures, but not insurmountable ones.  I think a lot of the issues with the information on their website is a result of poor translation, and a lot of it is contradictory because they updated one design or another but never updated the published specs.  Despite that, though, I think the products are pretty decent way to get something off the shelf that works.  I spent a lot of time running my i1500 next to a Missouri Freedom turbine, similar costs, and always pushing 3~5x the output.  I know that working better than a Missouri turbine is not a huge testament, but for people buying turbines off the shelf these are the options that don't reach into five digit costs.  The only turbine I've been disappointed in is their little i500...it just needs conditions to be too perfect to work well in my opinion.

I haven't played with their charge controllers and such, though, so I can't speak much of them...I haven't even looked at them.

As for the voltage issue...one way is high volts and the other high amps and neither one of them sound like pleasant ways to go.

[SparWeb]

But it's 4,000 Euros! 
I've had enough of their specs.

My overly paternalistic advice is to keep muckin' around with these toys on the cheap as much as you can.  Seems more fun and suits the way you work.  If you do decide to spend grown-up cash on a wind turbine then get serious and buy a machine with real accreditation, then do the tower and electrical install with professionals.  I don't know how to write that without sounding like a snot.  I hope you get what I really mean.  Play safe and all that stuff, too, you know.

[makenzie71]

It IS quite pricey and one of interests here is determining if it's worth the price...it helps that I get a discount

The nature of this turbine demands more respect than I've had to show some of my other projects, but the nature of my work means I have to explore unorthodox methods on the way.  It's weight, size, and output is such that I simply don't have any options in some regard.  It'll still be fun.

I believe I will be going with the on-grid version.  The appeal for the off grid version is that if I ever did want to build a massive battery bank then I already have a turbine that'll work, plus I could use the same simple equipment with this one as I have with my existing 48v turbines.  But that same simple equipment hasn't been super reliable and if I need to I can always run it through a transformer to bring voltage down and charge a bank.  Higher voltage I think will be slightly more forgiving and it'll let me try that thing I've always wanted to try: running a wind turbine through a modern string inverter.

[SparWeb]

the nature of my work means I have to explore unorthodox methods on the way.  It's weight, size, and output is such that I simply don't have any options in some regard.

but... uhh...  Haven't you noticed what this site is about??
Like, really, you haven't looked at ANY of the other projects here?