4 panel grid tie - advice needed

[lkruper]

The problem with those "quasi" grid tie plug in inverters is that even if they have the "anti-island" programming to stop working when the grid goes down there is no guarantee they will continue to work 100% of the time without having gone through a legal test procedure which is what a UL listing company performs. It only takes a single time for a failure to get someone electrocuted. So IMO those type of inverters will always have a "suicide cable" or at least a "Russian roulette" cord.

Thanks for sharing.... I was concerned I was being too conservative.

[SunEagle]

Thanks for sharing.... I was concerned I was being too conservative.

No problem. Your concern was correct and not conservative.

I will not trust any of those "plug in" grid tie inverters what ever they claim to be unless they have gone through rigorous testing which includes "anti island" disconnect function as well as any protection concerning over loading or short circuiting of internal components. That is what the UL listing provides.

[Sunking]

It is only natural some people feel like Codes are in place to prevent the little guy to shave a few dollars, and there is some conspiracy going on. I understand it, but seeing it from both sides IMO it is basic human nature to be selfish, now throw in some Ignorance on top of that. A lot of people that have been injured and killed, and trillions of dollars in property losses for each Code put in place. Some people just seem to not understand when you live in a community what you do effects everyone, many of which endanger your neighbors and community.

Technically there is no reason a Plug-N-Play Inverter cannot work. But the codes are not in place to assure it would work safely. For one the safety of the home owner wiring would require a DEDICATED CIRCUIT. Now your home, at least modern homes have a few Dedicated Circuit built in like the Fridge, Washing Machine and a couple of other Dedicated Use circuits. No problem adding another Dedicated circuit which is exactly what is required for a compliant method today, just no plugs, and hard wired nice and safe.

Don't hold your breath waiting for codes to ever allow such Plug-N-Play Inverters to ever be used in a code compliant manner. There is no one in the Industry who thinks having an Ineverter with Exposed Possible Live and Hot Circuit Conductors is a GOOD IDEA. Not going to happen.

Having said that I have one hundred units for sale. They are completely legal for me to sale. No refunds all sales are final.

[Cobs]

Im surprised the power companies OK it for these GTI's to be connected because it seems they do and there is a max limit of power you can feed in, this seems to vary company to company but is below 1500 Watts. The same applies to Wind Turbines.

I looked at the Transfer Switch, that does seem a very nice piece of kit indeed, unfortunately for me my Fuse Box is on the other side of my house so would take some wiring to get from A to B ... plus the extra cost of buying/installing.

Taking all the above into account i think my safest route would be to house the GTI in an Electrical Enclosure and have some Conduit from there to an AC disconnect switch - then conduit to an existing AC outlet - then remove the plug from the GTI and connect to the 3 wires inside the AC outlet thus connecting to the grid with the 3 existing wires. Suicide Cord is none-existant.

What say you guys?

[jflorey2]

Im surprised the power companies OK it for these GTI's to be connected because it seems they do . . . .

Why do you think that? Most do not. A lot of people get away with it because it often doesn't even offset their baseline load - but that's not the same as power companies approving of it. Most just don't know.

Taking all the above into account i think my safest route would be to house the GTI in an Electrical Enclosure and have some Conduit from there to an AC disconnect switch - then conduit to an existing AC outlet - then remove the plug from the GTI and connect to the 3 wires inside the AC outlet thus connecting to the grid with the 3 existing wires. Suicide Cord is none-existant. What say you guys?

That would definitely be safer. But if you are going to do that, and put all that effort into it, why not take the same effort and put it towards a real system? It would suck to do all that work and then have an inverter burn out and start a fire, or get a letter from your utility that they have seen power being fed back to the grid and are sending out an inspector.

[Cobs]

I guess you could be right that they dont know about it.

I do plan to have a full installation, i have had 2 price quotes, i am just deliberating

What is the difference between the GTI im using and one Professionally installed? Surely both are doing the same thing? Or we can use the same model? I can get an electrician to sign off the work also. Im not pursuing this option now by the way - just highlighting some things - which maybe have already been asked?

As for my 4 panels, looks like ill be making something Off-Grid to play around with, any suggestions peeps?

Cobs

[SunEagle]

I guess you could be right that they dont know about it.

I do plan to have a full installation, i have had 2 price quotes, i am just deliberating

What is the difference between the GTI im using and one Professionally installed? Surely both are doing the same thing? Or we can use the same model? I can get an electrician to sign off the work also. Im not pursuing this option now by the way - just highlighting some things - which maybe have already been asked?

As for my 4 panels, looks like ill be making something Off-Grid to play around with, any suggestions peeps?

Cobs

Usually those plug in type of inverters have not gone through the same (if any) safety testing and quality control requirements before they are sold. A Professional uses a UL listed grid tie inverter.

The other difference is that most UL listed grid tie inverters are rated for higher pv wattage. I believe the smallest you can get is now 3000 watts which would be over-sized for your existing panel wattage.

As for an off grid system, if you matched those panels with a 24volt 400Ah battery system and 45amp MPPT Charge controller you should be able to safely harvest about 2000 watt hours a day.

[Cobs]

Fantastic support and replies guys, thanking you all for your input, ill look into the 24v system - it would be a good match - with the panels 29.7 Volts?
Ill be harvesting more than that - i have a Wind Turbine to erect - up to 600 Watts on a good windy day ... so i might be torturing you guys a little more on integration

Cobs

[SunEagle]

Fantastic support and replies guys, thanking you all for your input, ill look into the 24v system - it would be a good match - with the panels 29.7 Volts?
Ill be harvesting more than that - i have a Wind Turbine to erect - up to 600 Watts on a good windy day ... so i might be torturing you guys a little more on integration

Cobs

It doesn't matter that they are 24volt panels or not. A good MPPT type CC will have a DC input around 150v so you can probably wire all 4 of those panels in series as long as the total Voc of all 4 does not exceed that 150v and it can usually charge battery systems rated 12, 24 & 48volts

If you add a Wind Turbine you will probably need to get a separate CC that is matched for wind and not just solar.

[Cobs]

Yeh the broader input range makes sense, ill start looking at some.

Im looking forward to this project, ill have to start sizing what i want to run in that room off grid and get the electrical enclosure / bits and pieces etc.

Thanks for your help SunEagle.

Cobs

ps ... For Off-Grid - which inverter is preferred? Modified or Pure Sine Wave?

[SunEagle]

Yeh the broader input range makes sense, ill start looking at some.

Im looking forward to this project, ill have to start sizing what i want to run in that room off grid and get the electrical enclosure / bits and pieces etc.

Thanks for your help SunEagle.

Cobs

ps ... For Off-Grid - which inverter is preferred? Modified or Pure Sine Wave?

Depends. What do you plan on running with that inverter? Some electronic devices or small motor loads (refrigerator) will either not run correctly or run hot with a modified sine wave. A Pure sine wave cost more but provides more options on what you can run from it.

I would hate to save a $100 on an inverter only to lose a $200 piece of equipment that didn't like the quality of power it was given.

[Cobs]

A Tumble Dryer, a DishWasher, some 12v heat lights for my Chicken Coop for cold nights, my Drill or other power tools, not all at the same time though, ill have to time their cycles, anything that i can get off the grid really but theyre the closest items to/in that room thats not on 24/7

Pure Sine Wave it is then, i guess i should be looking at a 3000Watt model or so - depending on the ah on the batteries, still some things for me to work out here yet.

[inetdog]

A Tumble Dryer, a DishWasher, some 12v heat lights for my Chicken Coop for cold nights, my Drill or other power tools, not all at the same time though, ill have to time their cycles, anything that i can get off the grid really but theyre the closest items to/in that room thats not on 24/7

Pure Sine Wave it is then, i guess i should be looking at a 3000Watt model or so - depending on the ah on the batteries, still some things for me to work out here yet.

Do not plan to use either the water heating or the heated dry feature of your dishwashwer. Either would use a prohibitively high amount of energy.
Do not plan to run an electric tumble dryer. You could run the controls and motor of a propane or natural gas dryer though.

You need to actually measure and calculate the sum total of the daily loads (in watt-hours, not just watts) before you can take the next step in system design.

[Cobs]

But that is the plan - to get a few greedy appliances off the grid, i know they will use an amount but if i can match the battery size to do it then its mission accomplished. I have one of those meters that shows the watt/hrs info, just havent got round to measuring yet, i know the cycle times so im half way there

[lkruper]

But that is the plan - to get a few greedy appliances off the grid, i know they will use an amount but if i can match the battery size to do it then its mission accomplished. I have one of those meters that shows the watt/hrs info, just havent got round to measuring yet, i know the cycle times so im half way there

If you destroyed those greedy appliances, you could make sure they never get used to pollute our planet