I want to build a 1200w grid tie solar system that I can plug into the side of my home.

[cs1234]

I absolutely do not want to hurt anyone. I'm just trying to get some cheap solar juice and turn it into cold.

It's a GTIL, if there is no grid power, it turns off, once power comes back on, it turns itself back on. There really isn't any statistically significant chance of hurting a lineman with a GTIL or microinverter anyway. I just wanted to make doubly sure it stays off until I'm ready to turn it back on.

Additionally, I have mine set to cover my household base load.. things I always have on sucking power. If there is a power outage, those things won't necessarily be back on instantly, and I would be injecting power back into the utility, which I don't want to do. The yellow plug I linked to, keeps that from happening.. as I have to manually turn it back on.

 

[cs1234]

understood. Is there a unit that does slightly more watts? The media 12000btu does 1300 ish watts and that's where I'm trying to get to. Or would you recommend I eat the other 200 ish so I can be sure I'm not backfeeding.

You can hook up as many of those GTIL's I linked to as you want. If you need more power, use more GTIL's. They don't mind. They are even able to use the same the same CT box for multiple units.

 

[rebellyellsolar]

It's a GTIL, if there is no grid power, it turns off, once power comes back on, it turns itself back on. There really isn't any statistically significant chance of hurting a lineman with a GTIL or microinverter anyway. I just wanted to make doubly sure it stays off until I'm ready to turn it back on.

Additionally, I have mine set to cover my household base load.. things I always have on sucking power. If there is a power outage, those things won't necessarily be back on instantly, and I would be injecting power back into the utility, which I don't want to do. The yellow plug I linked to, keeps that from happening.. as I have to manually turn it back on.

You rock man, thanks for all the help. Any more advice?

 

[rebellyellsolar]

You can hook up as many of those GTIL's I linked to as you want. If you need more power, use more GTIL's. They don't mind. They are even able to use the same the same CT box for multiple units.

Looks like I will need two to get enough juice to not worry about sucking anything in for the ac. Not that thats a terrible idea. Just the one, that is. I was just hoping for a little more haha.

 

[cs1234]

Looks like I will need two to get enough juice to not worry about sucking anything in for the ac. Not that thats a terrible idea. Just the one, that is. I was just hoping for a little more haha.

Nothing wrong with starting off with one and some panels and see how you like it.

Personally I have mine hooked up to batteries, and the batteries are charged by a separate MPPT controller. I want to use all the sunlight I can capture, if you have 2000watts of panels, to cover your AC unit, but you don't have 2000 watts of load all the time on your circuits, you are wasting some of your solar panel input. That AC unit isn't likely to be running at full load the entire time.

 

[zanydroid]

You can hook up as many of those GTIL's I linked to as you want. If you need more power, use more GTIL's. They don't mind. They are even able to use the same the same CT box for multiple units.

Problem with adding more GTIL is that you can get into trouble with AC output limiting if there's a configuration issue. For instance if you get 2x 1000 you are over capacity for a 15A branch circuit.

At some point adding an AC breaker or fuse would be smart.

 

[rebellyellsolar]

Nothing wrong with starting off with one and some panels and see how you like it.

Personally I have mine hooked up to batteries, and the batteries are charged by a separate MPPT controller. I want to use all the sunlight I can capture, if you have 2000watts of panels, to cover your AC unit, but you don't have 2000 watts of load all the time on your circuits, you are wasting some of your solar panel input. That AC unit isn't likely to be running at full load the entire time.

Okay, Ill consider a battery also.

 

[rebellyellsolar]

Problem with adding more GTIL is that you can get into trouble with AC output limiting if there's a configuration issue. For instance if you get 2x 1000 you are over capacity for a 15A branch circuit.

At some point adding an AC breaker or fuse would be smart.

May just vibe with the one. to see like cs says, the difference in power would be negligible and I could always scale it later or do another system like it in another part of the house on a different circuit. Just wish I could get a reliable gtil in 1500 ish watts

 

[cs1234]

May just vibe with the one. to see like cs says, the difference in power would be negligible and I could always scale it later or do another system like it in another part of the house on a different circuit. Just wish I could get a reliable gtil in 1500 ish watts

Figure out what your house "base" loads are. How much are you always consuming, at a bare minimum. To save electricity cost, you don't need to necessarily care about "peak" amounts you use, they are short lived and hard to predict.

See if you can get some solar panels, some batteries, and the GTIL. Then set it to cover your base load for 24 hours or whatever you can afford to cover battery/panel wise. It will be a smaller number, but you will save the same amount of money on your electric bill covering your base loads vs covering peak loads.

For instance, I have a base load on one of my 120v circuits of roughly 300 watts.. all day, 24/7. I have my GTIL set to inject 200 watts, and it does that 24/7 until the battery runs empty.

This keeps your current on the wiring lower, reduces the need for more GTIL's and if you have another inverter around, you might even have some charged batteries during a power outage, depending on how much you had left in your batteries when the outage occurred.

 

[rebellyellsolar]

Figure out what your house "base" loads are. How much are you always consuming, at a bare minimum. To save electricity cost, you don't need to necessarily care about "peak" amounts you use, they are short lived and hard to predict.

See if you can get some solar panels, some batteries, and the GTIL. Then set it to cover your base load for 24 hours or whatever you can afford to cover battery/panel wise. It will be a smaller number, but you will save the same amount of money on your electric bill covering your base loads vs covering peak loads.

For instance, I have a base load on one of my 120v circuits of roughly 300 watts.. all day, 24/7. I have my GTIL set to inject 200 watts, and it does that 24/7 until the battery runs empty.

This keeps your current on the wiring lower, reduces the need for more GTIL's and if you have another inverter around, you might even have some charged batteries during a power outage, depending on how much you had left in your batteries when the outage occurred.

Can I just use cheapo walmart 12v car batteries or is that generally frowned upon?

 

[cs1234]

Can I just use cheapo walmart 12v car batteries or is that generally frowned upon?

The GTIL in question requires 24vdc battery configurations. You could use two walmart batteries if you wanted, but.. Two 12vdc lifepo4 in series or one 24vdc lifepo4 battery from Amazon would cost more than some walmart car batteries, but they would provide significantly more watt hours of usable battery power. Especially when charging daily and draining all the way to empty, that will kill lead acids, but lifepo4 doesn't care.

 

[rebellyellsolar]

The GTIL in question requires 24vdc battery configurations. You could use two walmart batteries if you wanted, but.. Two 12vdc lifepo4 in series or one 24vdc lifepo4 battery from Amazon would cost more than some walmart car batteries, but they would provide significantly more watt hours of usable battery power. Especially when charging daily and draining all the way to empty, that will kill lead acids, but lifepo4 doesn't care.

I see, what size would you use in my case? Also, when you say significantly more, how much more?

 

[OM617YOTA]

I built a completely off grid system, batteries and all, and ran an extension cord to a window unit. Worked just fine. No possibility of back feeding, and backup power during outages.

 

[rebellyellsolar]

I built a completely off grid system, batteries and all, and ran an extension cord to a window unit. Worked just fine. No possibility of back feeding, and backup power during outages.

I'm okay with a little bit of backfeed for my needs. I live in an area with very stable power most of the year. My needs are to dump energy into something to offset my ac cost, and maybe having a secondary inverter and using a battery for a smoother power curve are good additions. But like. What I want, is to generate and dump. I'm less intrested in storage.

 

[cs1234]

I see, what size would you use in my case? Also, when you say significantly more, how much more?

It really depends on how much solar you are going to be able to put in. You only need the batteries to maximize solar to feed into the GTIL.

How much solar panel wattage do you think you're going to be able to place/purchase?

 

[rebellyellsolar]

It really depends on how much solar you are going to be able to put in. You only need the batteries to maximize solar to feed into the GTIL.

How much solar panel wattage do you think you're going to be able to place/purchase?

1200 - 1500 watts 4x 300-450watt panels

 

[cs1234]

1200 - 1500 watts 4x 300-450watt panels

Are you able to backfeed / export to your utility without getting in trouble? That is going to determine the optimal next step.

If USA, is it an old style analog meter, or a newer digital meter? If analog, you can probably export and it will literally just turn backward if you give more than you take. If digital, they have the ability to know almost instantly if you export anything significant to them.. what they will do with that information varies, but they tend to not like it.

 

[rebellyellsolar]

Are you able to backfeed / export to your utility without getting in trouble? That is going to determine the optimal next step.

If USA, is it an old style analog meter, or a newer digital meter? If analog, you can probably export and it will literally just turn backward if you give more than you take. If digital, they have the ability to know almost instantly if you export anything significant to them.. what they will do with that information varies, but they tend to not like it.

No, this is sort of a cross my fingers kind of deal. It's a digital meter. I don't see a feasible means to clamp to one of the wires in there without it being found by insurance inspectors who come knocking once a year. The panels and system can otherwise be explained as a self contained ac system and it could be wired as such in minutes, with a battery and other stuff, I assume. The thing is, all of that noise is all together more expensive. I know the system is going to be more effeciant than my inbuilt system. The central unit I have, I looked up, pumps out 18,000 btu at 1384w. A media is 2/3rds of that so we stack 35% greater efficiency + effeciancy gained by not using the main ac as much on top of 2/3 less power usage I mean, thats nice. I guess I want to do this for less than a grand, and compare year over year to see what my actual savings are. What would you do?

Edit: The 35% comes from me using a media and not a standard window unit, but the window unit will also, be more efficient than my internal. Seer 13 vs 15

 

[cs1234]

@rebellyellsolar

You would gain the "cost savings" in electricity by simply using the window unit, even without the GTIL or solar panels.

You are going to end up backfeeding / exporting briefly every time your AC unit ends its cycle. Whether they will notice and beat down your door or not, I don't know.

The only way to run a GTIL and not get caught if exporting isn't allowed is to never generate more than you are using.

Do you have any idea what your minimum electrical load, your base load is? If not, might I suggest hooking up something like an Emporia Vue 2 (which are allowed, even by inspectors). Once you know your base load, you can determine if one GTIL, a few panels, a small MPPT and a 24v battery is something to get or not.

Alternatively, what others suggest is the way to go.. get an inverter, that can run with solar and ac with no batteries, hook up some panels to it and your ac unit. Whatever the panels don't supply, your existing AC service will provide with no fear of backfeeding / exporting. They are more expensive than the GTIL I mentioned, and they can't offset any loads that aren't connected directly beneath them. There are a few out there that can do this, but I don't have any to recommend personally.

You could also use a mini split, and instead of drilling through the walls, just run the cables through a small insert through the window. There are mini splits available that do ac/solar power, like the EG4.

I just don't like wasting solar panels output. Having them connected directly to a load that doesn't use their full output every second they are producing during the day is going to result in some of their ability being wasted compared to an MPPT/battery. Some people on the forum are cool with that, with overpaneling in general, but I'm not one of them.

 

[rebellyellsolar]

I have my electric bill that gives hourly, daily and yearly summaries. I imagine this data would probably be sufficient if you wanted it. If you need daily's let me know.