Grid Tie Inverters

Need to build these for the windy name and see what it would take to get it UL approved..

 

If you do not need to have the transfer switch work automatically and just want to do it manually I found a 3 pole double throw 30 amp switch on e-bay for a great price. I will post the link mark99 http://cgi.ebay.com/30A-Three-Pole-Doub ... 4152456170

 

The more we learn, the more questions we have. Pros & Cons

Pros.
The reason we decided to use an auto relay was to take advantage of the inverter turbines power if I was not home during a home grid failure and also not require the turbine to be under a constant brake.

Cons.
BUT... Now what I also have to consider, is my dump load adequate to now handle two turbines feeding my bank if I am not home to increase the banks workload !
I am using two 300 watt Wndy coils and I think at a minimum should be adding one more.

I also like the alternative Mark is offering on the use of a manual relay. This has come about due to our discussions on my battery bank setup during normal home grid operation. We are loking at the option of setting up low volt in grid tie inverters and switching over to the batteries on occasion for maintenance to ensure they are healthy to use for back up during power outages. :idea:

 

Murry,
These are good questions. I did give some thought to your dump load size. I went back and forth because you are right we are adding a large charge load to your battery bank. Still you have a 600watt dump load that bleeds your batteries down when they are full. It might be a little light in a really bad wind storm but for day to day operation I thought it would work well. This is a good question for Windy. If you do add another 300 watts to your dump load make sure you size your solenoid and wire to handle 75 to 80 amps. I understand that you hate to waste any wind power. One alternative may be to set up two charge controllers on your battery bank. Set them 1 volt apart. Have the first one close a relay at 12.5 volts to turn something on like an electric auto heater. That is what I use for my dump load. It has a low and high setting, 300 and 500 watts. Then have your normal dump load set at 13.5 volts. If the heater or any other load you put on the first controller does not drain the bank enough the normal dump load will.
The point about you made about not keeping the wind mill loaded with a battery bank if you are not home to switch it over was something I did not think about. I have never used a grid tie in inverter but you have me thinking about them now. You are right it needs to be automatic to keep the windmill loaded now that you are not using the safety relay.
I have been looking for a 3 pole double throw 30 amp relay with a 120 volt coil since we started down this road. I found one today and it is UL listed. I like it better then our first set up. I am going to order a couple tomorrow. I will keep you posted Mark99

 

I think Murray has the 100 amp, 12 volt charge controller. This is good for up to 1300-1400 Watts of dump load capability. So, Murray you could add up to four of the 300 Watt resistors (1200 Watts total) if you think it is necessary.

I think for your current system, when both of your turbines are charging the batteries, three dumploads will be OK.

 

you are right, I do have the 100 controller. I use# 8 wire and 70 amp in line fuses.
I also agree with you on having the 3 dump loads..
Adding the third would just be safe guarding in case the home grid power goes out while I am not home
There would and would not be an increase in the amount of volts being dumped.
Still dumps from a 12 V bank when reaching 13.7.
The only difference would be if I was not home to increase home use it would have to dump more often.
A lot more often :lol:

murray

 

I just ordered my 300w Grid Tie and asked the question if I could use it as a dump load. No matter what question I ask. The answer is No hook to Battery. Damage will result.
Guess they just sell and have no other answer.
The grid ties are cheap and will only serve 1 purpose. They have no voltage or current protection.
Buyer Beware. If you exceed the rated wattage. 300w= 14v x 20a derated a little as not to run it at max. You will damage the unit.

Asked Do they make one that can be hooked to a battery. Answer........NO Hook To Battery.
But if you really want to use it with a battery. :ugeek:
I will have to see how long it lasts going from battery-----inverter------12v 20a switched supply---Grid Tie----Grid. Should loose about 15-20 percent but it should work. :ugeek: Was going to dump and make heat anyways.

[attachment=0:38mpudyb]PowerInverter.jpg[/attachment:38mpudyb]

This is the one I bought.

 

Back at you on the Sun 500 inverter I bought. 10.8 - 30 V, internal rectifier, dump load capable terminals, auto over volt protection.

I did not wire it in as a finished deal because I still don' t know which turbine sight I will run it at.
For now it is working on the front end of a Power Jack 1200, 28 - 55 V and recieving from a Windy 500 ( no furling)
For now just wired it parallel off the main rectifier and straight to the unit as it's takes AC feed and uses it's own internal rectifier. The rest of the wiring stays as is, runs of the rectifier as DC current to an SWEA, AP box which is controlling my DC volts at 56 and has a SWEA dump load.

So now to the action......in the 5 minutes or so that I watched the Sun 500 was showing up to 310 watt on the meter and dropping down to low watts following the available wind. As the volts built up you could see the Power Jack light up while the Sun was still working, this was a fine line as one was finishing at 30 & the other had just kicked in & 28 v .
I do not have a dump load hooked up to the Sun 500, instead I have followed Larry's formula and allowed the over volt protection to work and it does. When it builds up to excessive volts the inverter shuts down and my Power Jack continues.
I did not have a meter on the Power Jack yet so no watts to report on it.

What do I think, well I have bought one that works as advertised and I do not have to tune anything !
I am now turning low volts into usable energy where before the turbine was just spinning.
The cost is not all that bad, BUT after the Can., US currency exchange, international shipping costs and the dam Canadian Customs Fees, the cost creeps up on you ! ( if you are an international customer )

I will give it a chance where it sits now and give some thought to moving it over to the Windy 750 with 4 SWEA 250 watt inverters, & maybe pulling a real Larry and start adding more turbines to the feed. :lol:

 

Well Good News and Bad News.
Sun G 500 AC 10.8 - 30 V
Good news is this inverter works great. I am picking up watts in winds so light that were just making my turbine spin and look good but giving me nothing before .

Bad News is I wanted a DC version of this inverter so I could feed it with more than one turbine if I chose.

So big question to everyone, we know that you can combine the DC volts from multi turbines after their respective rectifiers BUT can you tie more than one turbine together on their AC side. How would this affect them ?

If this can be done, I am ok !
If it is not possible, I will sell this new inverter to anyone who wants to run off of just one turbine. You can have $50.00 off my cost price, plus your shipping. ( I paid $ 249.99 EBAY)

 

Well like the grid tie inverter that I am still waiting for. I checked out a few computer power supplies I have. And they will not be good enough. So I ordered a 12volt 20amp transformer today. I will run it through a rectifier and a capacitor filter. Then on to the grid tie and see how it all works out. Will probable be a week before I get it all together. Then I will report back and let everyone know how it does. It should not burn out the grid tie but will have to wait and see.

 

Hey Murray, I am not the best with AC voltage but i would think that they would try to brake each other if you have them connected together. One thing you could do is run each wire through a blocking diode just before the inverter that way the 2nd generator wont feed back to the first and vic-versa.

 

Plain words no you can not. Will cause braking of all units. Remember these are motors and generators. One will produce more volts and try pumping to the other and brake it.

 

Well Tom, that is what I thought also,,,, just didn't want to hear it :cry:

So if I do not hear from anyone on the forum today who would like to get a good deal on it, I will be shipping it on Wedensday back to the seller for an exchange!

You know Iam really looking forward to the day when I do it right the first time :roll:

 

thanks dlmcbm, you were the first bearer of bad but accurate news. the seller has agreed ti do an exchange. But you all know there will be a cost to pay.

 

The Grid Tie I got today is a SUN-330G. User instructions say for wind or solar. Also no reference to battery no hook up damage unit.
My 12v 20A transformer is on the way. I gave up on power supply. It probably would be fighting the Grid Tie trying to get max power and power supply adjusting for least power. Should be here in a few days. :roll:
[attachment=0:1xz970sa]PowerInverter.jpg[/attachment:1xz970sa]

 

Also opened it up and it has 16 MOS in the grid tie.
[attachment=2:7cx4v73d]SUN-300G.JPG[/attachment:7cx4v73d]
They have a clamp for each pair and it is screwed tight to the case on the side of the unit.
[attachment=1:7cx4v73d]FetsonSide.JPG[/attachment:7cx4v73d]
Which is better than the power Jack video I saw and they were installed loose nothing holding them to a heat sink case. Solder joints look good.
Only 2 things I do not like. The fan has a bronze bushing.
[attachment=0:7cx4v73d]FanBushingType.JPG[/attachment:7cx4v73d]
They tend to seize up. I found this out while working on computer fans. Ball bearing is the only way to go for long term. But if it does stop pull the end panel off. Unscrew the fan. Peel back the sticker in the middle of the fan and oil the sleeve with real light oil. I just had to do this to my inverter. :geek: The other is the power cord. How much could it cost to ask 115vc or 230v and send the right cord. But that is just a little deal. I will just cut the end off and wire a 230v cord on. I prefer to Balance out the power on the grid. I will be adding more.

 

Thought I would try this while waiting for transformer.
[attachment=0:13zsi2gp]GridTie2 001.jpg[/attachment:13zsi2gp]
I fuse protected the Grid Tie and the diode blocks the battery from the Grid Tie. Done this way the Grid Tie will run and most if not all should go to Grid Tie. But if Grid goes down and it goes to Island mode the power will go to the Battery. Will hook up and do some readings over the next few days. Yes I know there will be power loss thru the diode. :geek:

 

Morning Tom,

What are the sizes on the fuse / diode ?

What do you have for a dump on your battery side ?

Can't remember if you told us already how you will over volt protect the inverter !

 

Arent you worried about to high of a voltage to the GT tom? you just eliminated your voltage clamp that way. If you were running the 22-60 prolly wouldnt ever matter but a 10-28 MIGHT go over in really strong wind..Prolly not,more concern of the grid going down and frying the 12v battery if you were not around to add a load to the battery..

 

No I put it between the rectifier and the clamp rectifier. It will still clamp the voltage. If something does go wrong the 10 amp fuse will blow before it over loads. I also still have the charge controller hooked to the battery and dump load.