Questions About 200W Grid-Tie Inverter

[nathanca]

I recently purchased a 200W Enviro-techs SSI-200 Grid Tie Inverter to use with a 200W wind turbine, but still have some questions about the inverter. Is anyone else out there using this inverter?? They seem to be selling well on e-bay, but I'm having trouble finding anyone who's actually using one. I know it's not a huge system, but the low cost and (supposed) simplicity really got me interested.

So, the turbine is apparently 12V while the inverter range is 14-28V(see specs below), but several people assure me that the turbine will reach that range at higher speeds, so I'm willing to test it out for now, and maybe replace the turbine generator motor later.

But, someone in the wind forum said that the turbine could actually exceed the input range in very high winds, and burn out the inverter and turbine... and that would suck. Does anyone know if this is really a problem, or if the inverter's overload protection is sufficient?

Ok, here's the specs for the inverter:

Enviro-techs SSI-200 Grid Tie Inverter

Maximum Peak Load 250W

Electrical Specifications - Output:

Model: SSI-200W

Nominal AC Output Power: 200W

Maximum AC Output Power: 250W

AC output voltage range (220V): 190V - 250V

Frequency (220V): 46Hz - 65Hz

AC output voltage range (110V): 90V - 130V

Frequency (110V): 46Hz - 65Hz

Total harmonic Distortion (THD): <5%

Power Factor: 0.99

Island Protection: Yes, inverter shuts down during black out

Output current waveform: True sine wave

Electrical Specifications - Input:

DC input voltage range: 14V - 28V

Peak inverter efficiency: 91%

Over-current protection: 20A

Reverse Polarity Protection: Yes

Power consumption (Standby): 1W

Stackable: Yes, unlimited

Mechanical Specifications:

Operating temperature range: -20'C - 65'C

Weight: 1.2kg / 2.65lb

Dimension (L x W x H): 15.2 x 14.3 x 5.7 cm 6.00" x 5.63" x 2.25"

Mounting: Wall Mount

AC Cable Length: 1.5m

Cooling: Convection cooled with fan

Display: 3 Green LED + 1Red LED

Voltage Switch: 115V, 230V

Features:

- Grid-Tied - sell green power directly back to the grid at a premium rate

(depends on your location)

• Maximum Power Point Tracking (MPPT) - optimize power output
  
• Plug and Play Design, simply plug into an outlet (GFI), no hard-wiring
  
• Stackable (connect in parallel for higher output)
  
• Island protection: Inverter will shut down during black outs.
  
• Simple and safe installation
  
• Reverse polarity protection
  
• Generates pure Sine Wave
  
• Constant Power Output
  
• Low distortion output on all ranges
  
• Allow different Power factor from loads
  
• Does not require rewiring of existing electronics
  
• LED indicators to reflect power output rate
  
• Compact and light weight design
  
• RoHS Compliant
  

[RUFUS]

Dude

 if thats the same one been out there a while

it't made in the netherlands or china and neither

place cares who you electrocute. maim or injure

aparrently they have different laws about this

 kind of stuff (death by dumbass) they dont

have any kind of real certifacations or a UL stamp

Please do your home work and buy a reputable system

and do everything correctly, you might be the one

who saves a life from junk like that

But like i've allways said "i'm no expert but"

be very dilligent in your safety practices.

see my previous posts on this subject.

                              RUFUS

[CmeBREW]

Looks like you are in some 'unchartered (or is it uncharted) waters'.

So, you are trying to use this small Grid-tie inverter ONLY with a small windmill which will go on and off hundreds of times each windy day. I wonder if the inverter can handle this?

I do not see how in the world the two 12v batts in series could work since the inverter will drain them down and ruin them when the mill is doing nothing.  That makes no sense to me.

I would ask those guys who sold it to you a lot more questions.

Does the inverter have it's own internal voltage regulator?  Or do you need to get your own (optional) voltage regulator to keep it (The windmill's open voltage) under 28vdc so it don't blow up the inverter circuits?

Does the low voltage RE sources power the circuits of the inverter, or does the grid power (120vac) power the circuits?  (BTW, only 1W idle is good)

It would be interesting to see that inverter hooked to an Oscilloscope while the  voltage of the windmill is constantly going up and down to see just how 'regulated' and 'pure' the sine wave inverter output really is.

Many of us WISH something like that could work and be passed by UL for legal use in US, but I think many are doubtful.   If there is any distortion it could cause all kinds of 'noise' problems for electronics like TV's, lcd's, radio, even for your neihbors down the street, etc...

-

I was wondering if this is the motor you got with that "200Watt mill": (if it isn't, then disregard)

http://cgi.ebay.com/2-25-HP-260V-treadmill-duty-DC-Motor_W0QQitemZ280305004777QQcmdZViewItemQQptZExe
rcise_Fitness_Cardio?_trksid=p3286.m20.l1116

-Hope you can get it sorted out.

[ghurd]

chartered. charted.

Either way. Water is boo-koo bad.

[nathanca]

No, I don't think that is the same motor... mine is slightly smaller, and actually doesn't have a label on it, not sure why.

[nathanca]

Well, I'm realizing that this is 'uncharted' territory, but at the same time I think this could be a huge deal for the future of energy production. Most people are like me, living on the grid, but wanting to produce some clean energy, without a huge initial investment of time and $$. I don't even have mine up and running yet, and already my friends and family all want their own (once the details are cleared up).

I believe the grid powers the inverter circuits. I am asking more questions from the inverter seller, we'll see what he says.

Think I need to learn a little more, but as good luck would have it, I found a 1-day class on small wind systems here at the university, though it's not until April.

So... would anyone recommend their best ideas here? Should I look into a battery bank and charge controller? Hmmm...

[nathanca]

So I've been searching around, and I'm thinking I need an overload relay between the wind turbine and the inverter, to keep the inverter from being over-loaded. Ideally, I would direct the over-load to a water heating element of some sort, situated in my pool. Does that make sense?

Looking around, there seem to be a lot of overload relays at affordable prices, but I'm not sure which one to get. I read that I must use a DC overload relay, since an AC one wouldn't work right, but none of the relays seem to specify which they are. And then there are all these different ratings and ranges, not sure which I need for this system?

[cardamon]

A (properly sized) good quality inverter used with a compatible wind turbine will keep the turbine loaded appropriately to keep the voltage in the required range. To be safe, some systems have an extra over-voltage protection stage before the inverter, such as a windy girl for example. I don't think anyone denies that your system is a bit sketchy and unproven, so it is unclear how well the inverter will play with the turbine, i.e. where it will keep the input voltage by controlling how much power it is trying to draw.  over-current may be an issue as well during gusts and other high wind events.  For example, my "1000 watt" turbine has pushed 1100 watts into my batteries and that is with considerable transformer and rectifier losses. What I would try is put a TRI STAR TS-45 set to diversion mode on the input of the inverter and set it to divert at 26 volts, that is likely just about as low as it can be set for a 24 v system (you could experiment with that figure).  You would need a 24 volt water heater element (or equivalent)as your diversion load.  You could also size up by ohms law the correct length of 16 guage copper THHN and throw it in a bucket of water and use that as your diversion load for starters. I would think that would protect the inverter sufficiently.

[(unknown)]

I am helping a friend with a system, 2 700 watt ARI turbines w/4 panels and a 24 volt battery bank. He runs a 24 volt inverter to run the house hold items and a envirtechs ssi-200 watt grid tie inverter. The unit works great and safe. unplug it and no output. At 25 volt input we have a 231 watt output, the out put will drop as your input voltage goes down. We are not worried about spinning the meter backwards because at this time we just want off set are usage. we hooked up the old style dial meter and if we drop all of the load in the house it will spin the dial back. I have done a number of safety checks with the unit and it is safe. Most of these grid ties are all based from china. I know because of woking with some of the others on the market. I read somewhere that they will have a 1000 watt unit UL list in April sometime. As for the ARI wind mills I have one and love it, have it feeding into some 1500lbs 24 volt fork lift batteries then take that to another shed to drop it to 12 volts and have a small battery bank at 12 volts and use a 12 volt inverter, to cheap to get a 24 volt inverter.

[(unknown)]

DO NOT HOOK THE INVERTER DIRECTLY TO THE TURBINE!!!!!!!!!!

I am using two of these 200W inverters. They have a 20 amp breaker to protect themselves. They are simple and very easy to use. I have a 24V turbine. What happens is, the inverter keeps a load on the turbine. In my system my turbine puts out around 24V open circuit (meaning without a load). When it is connected to my inverter it creates a load and drops the voltage of my system to around 18V. I have 4 12V batteries wired together to get a 24V bank. If the turbine is producing little or not at all, the inverter drains the battery bank down to 14V and the inverter shuts down. If the turbine manages to produce over 28V the inverter WILL shut off. As long as the turbine isn't putting out over 20Amps your fine. Once it reaches 28V i have a DC diversion load that runs a heater to burn off the power and keep a load on the turbine. Basically my turbine and my inverter are both wired to the batteries. I have a regulator that connects my diversion when the voltage reaches 28. The only reason I have the batteries is to keep a load on the turbine until it is running high enough for the inverter to kick in.

Regarding the 12V system i don't know whether your turbine puts out over 14V. If you're using this grid-tie inverter you will need to create a 24V battery bank. Yes your batteries may be at half charge most of the time. Unless you have your voltage from your turbine regulated, you run a high risk. a 12V system should never exceed 13.5 volts for an extended period of time.

Since you are using a 12V turbine and a 14V minimum inverter, you will not be able to harness any power if the voltage is below 14V. This means you will only get power in high wind.

You will NOT burn out the inverter. I have had my heater running for hours on end at times when it is very windy. 28V will blow your batteries up before the inverters kick out if you have a 12V battery bank. A 24V battery will be able to handle this.

Look online on how to wire 12V batteries together to get 24V.

DO NOT HOOK THE INVERTER DIRECTLY TO THE TURBINE!!!!!!!!!!

Only hook the inverter directly if you are wiring it to a solar panel.

Hope this helps.

[ghurd]

Let me see if I understand what you are doing...

You have a 24V battery bank, and the inverter runs it down to 14V, by feeding the power to the grid?

You saw a video or something from the retailer, who did NOT show it connected to the grid because of good sense and a lack of the UL listing, but you admit publicly you have 2 connected to the grid?

You believed the crap instructions from the retailer, instead of anyone bothering to understand the design?

(it doesn't take a rocket scientist to see the design parameters, but these 'dealers who are expurtz' can't figure it out)

I do agree with do not connect it to a turbine without a battery.

[bzrqmy]

I have seen these units on E-bay as well, but sometimes sold with solar panels. Instead of the output of the inverter having an outlet to pulg your appliance into, it comes with a pigtail they you plug into a wall socket.

OK, so the manufacturer claims that the inverter has a sort of LVD circuit to not drain the battery.  They also claim to have Island protection in the event of a grid failure to prevent back-feeding the grid. They claim the inverter matches the frequency of the grid.  All things a grid tie inveter should have.  What it does not have is the UL listing.  Although I have not checked, I bet in most places it is illegal to connect this to your house wiring.

My question is;  Will something like this ever be for real?   Just think.  If us DIY grid connected guys that are dabbling in wind/solar and do not necessarily want to store several days worth of power could have a small battery bank, and put our power back in to the grid to offset our consumption.  And do it for a couple hundred bucks?  It would solve all my problems trying to match loads to what the wind is doing in a given day.

Like everything else, economy of scale will bring prices down.  Today a grid tie inverter will run you at least $2500 before you pay someone to install it.  You can buy new notebook computers for $250 now.  Will this ever happen to the RE world?

[ghurd]

I believe the 200~250W units function as designed, if not as the US retailer written instructions say.

The UL sticker is not cheap.  I believe the demand for a little GTI would have to be higher for a device with little chance of paying itself off to make it worth getting the sticker.  The cost of the sticker will certainly jump the retail cost quite considerably, which will make the 'cheap little Chinese unit' not cheap, which lowers the demand.  I suppose the 'manufacturers' figured this out, and that's why there is no sticker.

The physical requirements to connect it legally are not cheap either.

I think they need a utility accessible disconnect, meaning a specialty, low demand, outdoor listed, power switch, that costs more than the inverter.  There went the "do it for a couple hundred bucks", even if the inverter was free.

I have no idea what it costs me for an actual KWH, but my bill says the part I pay for the electric itself is about 6 cents.

In a great situation, maybe I can backfeed at 50% capacity (100W) 24/7/365, it will save me $50 a year.  ROI for the inverter and legally installed disconnect alone is maybe 10~15~20 years?

That's about when small GTIs get their low demand characteristics.

G-

[bzrqmy]

Well said.