GTIL2 and Solar charge controllers

[thom72]

I currently have fifteen 325watt solar panels and nine 275 solar panels along with qty 12 115ah batteries. I am trying to build a system that will take in the watts from my panels and send it to the charge controllers and then from the batteries to a GTIL2 with limiter then to my home so I am not sending to the grid and only using it locally in my house but still being grid tied at the same time. I am trying to find out what the best size strings I should use as well as series or parallel or a combination of both. I want to go from the charge controller to the batteries to the GTIL2 with limiter and then to my home and using the batteries until they get to low then switch back to grid tie juice. I also want to mention, please excuse me for possibly using the wrong terminology due to me being new to this. I have seen the Midnite solar charge controllers in tandem but they are to expensive for me right now. Any suggestions on how to design this system and any less expensive controllers and GTIL2 inverters would be greatly appreciated. I have seen this done on youtube but can't get any answers and do I need anti-islanding

 

[DIYrich]

Where are you located?
Model numbers of everything you already have.

 

[thom72]

Where are you located?
Model numbers of everything you already have.

Thanks for responding. I will list what I have now and what I'm going to purchase as soon as I get home from work

 

[thom72]

Thanks for responding. I will list what I have now and what I'm going to purchase as soon as I get home from work

I'm located in Thompson CT

 

[DIYrich]

I'm going to purchase as soon as I get home from work

Wait to purchase. Do not pass go. Do not collect $200.

Do you have the GTIL2? If not, you should plan the entire system before buying anything. Largest I saw is 2000w, way underpowered for the panels you have.

You can't be grid tied without permits. You may want to go the extra step and get PTO from the utility. Is the GITL2 UL Listed?

 

[JoeHam]

There is plenty of information on the GTIL’s on the forum :

Search results for query: Gtil

diysolarforum.com

If you are only looking for anti islanding and grid supplementation most every all in one on the market does that better with a simple sub panel added.

The hot item right now seems to be the EG4 6000. Look around the forum and you will find all kinds of information.

By all means, stop purchasing stuff and get a plan together before going further.

 

[thom72]

I'm located in Thompson CT

Im sorry guys. I didn't mean purchase. I meant to say post what I was going to purchase once I get this figured out.

 

[thom72]

Wait to purchase. Do not pass go. Do not collect $200.

Do you have the GTIL2? If not, you should plan the entire system before buying anything. Largest I saw is 2000w, way underpowered for the panels you have.

You can't be grid tied without permits. You may want to go the extra step and get PTO from the utility. Is the GITL2 UL Listed?

I am trying to stay away from any contracts from the grid. They kill us here for any type of contract and all kinds of permits are over $4500 here for it as well.

This is what I have so far:
Solar Panels
15 - 325 watt , Impp 8.72A, Vmpp 37.3V, Isc 9.27A, Voc 46.0V
9 - 275Watt solar panels. I don't have the specs offhand.
Batteries:
12 - 12v 115ah AGM batteries from a UPS system. all the exact same and in perfect condition

And this is what I was going to purchase to supplement my home grid tie to bring my E bill down.

2 - Epever MPPT Solar Charge Controller 12V/24V/36V/48V Tracer AN

100A 80A 60A 50A Epever MPPT Solar Charge Controller 12V/24V/36V/48V Tracer AN | eBay

Battery Temperature Sensor Epever Monitor Adapter RS485/USB Communication Cable. Battery Temperature Sensor and Monitoring adapter RS485 to USB For Tracer MPPT. 1000W Solar Grid Tie Inverter 110V or 220V MPPT Pure Sine Wave Inverter From USA.

www.ebay.com

Model
MPPT
Current Type
DC
System Configuration
Off-Grid
Type
Solar Charge Controller
Features
All Daylight Conditions, Automatic Voltage Detection, Bluetooth Module, Daylight Operation
MPN
TRACER506080100A
Power
625W~5000W
Current Output
50A
Brand
Epever
Charging Mode
MPPT (Maximum Power Point Tracking)
Voltage
12V/24V/36V/48V


2 - SUN 2000W Solar Grid Tie Inverter MPPT Power Limiter DC45-90V AC230V 50/60HZ Auto

2000W Solar Grid Tie Inverter MPPT Power Limiter DC45-90V AC230V 50/60HZ Auto | eBay

3000W 24V Solar Hybrid Inverter AC230V Off-Grid Pure Sine Wave Inverter 80A MPPT. 5500W 48V On/Off Grid Hybrid Inverter Peak Cutting Valley Filling MPPT 100A. Peak Power Outputï¼2000W. MPPT Efficiencyï¼99%.

www.ebay.com

Charging Mode
MPPT (Maximum Power Point Tracking)
Continuous Power Output
1950W
Input DC Voltage Range
45V ~ 90V
Grid Tie Inverter with Power Limiter
Output Frequency
46Hz~65Hz
Output Wave Form
Pure Sine Wave
Peak Power Output
2000W

 

[thom72]

I just don't know how to make this fully offgrid if I can and only use Grid tie when needed. I am totally new to this and trying to learn. I do apologize for anything I lack knowledge on guys.

 

[kommando]

3 way switch between house, grid and solar/batteries. Position 1 house connected only to grid, position 2 house not connected to anything, position 3 house connected only to solar and batteries. Position 2 ensures the grid and solar/ batteries can never be connected at the same time as to get from 1 to 3 you have to pass through 2.

When you switch will depend on weather forecast and battery charge, when not connected to the house all the solar goes into the batteries.

 

[thom72]

so you are saying to place a switch between the grid tie on the house and the solar/batteries? What type of switch would this entail? I am also trying to figure how to figure the strings as well as what inverter to use and if I need a panel between the grid and solar setup to feed the house.

 

[kommando]

Wiring in the UK is not the same as in the US, no 120/240 just 240 but I use a 3 pole 3 position 100A AC switch.

https://www.cef.co.uk/catalogue/products/1779268-100a-3p-surface-mounting-3-position-changeover-switch-ip65

 

[DIYrich]

How many strings will you have (different orientations, shading, etc)? Depending upon the strings, you may want to consider a growatt.

If it goes in the house, then you will need permits.

 

[thom72]

I am unfamiliar with Shading but if this means any shade on the panels then they will be in sun all day except for over casting. I am also trying to figure what strings I can use along with parallel or series or a combination of the both.

 

[DIYrich]

Really rough numbers:

You have 7.3kW of panels. During the summer in CT, you may be able to produce 35kWh on a good day. That is enough to run a normal house for a day.

You have 5kWh of AGM batteries, of which 2.5kW is usable (vs 35kWh of production on a good day). The rest of the production will be wasted if not used immediately. At 0.20 cents per kWh, that 35kWh is worth $7.00 a day, or $2,000 a year. Consider the wasted energy in your decisions.

In CT, they have great net metering. The cheapest system to build that uses all the power is a grid connected one, get permits and permission to operate from the Electric company, and you are good to go. Electric company serves as your battery (above 2.5 kW) to shift power to when you need it.

At a minimum you will need permits to power the house.

Find out your max instant usage (AC turns on when running electric dryer, etc.), and that determines the pass-through rating you need for the inverter.

You want a 7kW of PV or larger inverter to handle the panels. you will need at least 4 independent mppt inputs (might be able to do it with 3) because you have an odd number of each panel. Or don't use 2 panels, and you can get by with 2 mppt inputs.

I would suggest buying something like the eg4 18kpv, and get it permitted and PTO with the utility. The ability to export should pay for itself in a few years (vs the cost of a cheaper non exporting system).

When your AGM's fail, if you choose the Sol-Ark 15k instead, you may be able to buy LIFEPO4 batteries and take advantage of the Energy Storage Solutions subsidy in Connecticut. Currently, Sol-ARk 15k is approved for ESS program, whereas 18kpv is not.

 

[thom72]

DIYrich, are you from CT? it sounds like it. That is cool that your from NE. So i would need permits to do the install and not have to use a company for the solar system to be installed. I was definitely trying to avoid the whole solar scam they are doing because a neighbor of mine got taken for a ride. I appreciate all of the input. I'm going to look into a total cost of going grid tie and checking with the electric company to see how I go thru their process. Just a dumb question, how would I figure MAX instant usage in my house? Is there a tool I use to meter this?

 

[thom72]

Really rough numbers:

You have 7.3kW of panels. During the summer in CT, you may be able to produce 35kWh on a good day. That is enough to run a normal house for a day.

You have 5kWh of AGM batteries, of which 2.5kW is usable (vs 35kWh of production on a good day). The rest of the production will be wasted if not used immediately. At 0.20 cents per kWh, that 35kWh is worth $7.00 a day, or $2,000 a year. Consider the wasted energy in your decisions.

In CT, they have great net metering. The cheapest system to build that uses all the power is a grid connected one, get permits and permission to operate from the Electric company, and you are good to go. Electric company serves as your battery (above 2.5 kW) to shift power to when you need it.

At a minimum you will need permits to power the house.

Find out your max instant usage (AC turns on when running electric dryer, etc.), and that determines the pass-through rating you need for the inverter.

You want a 7kW of PV or larger inverter to handle the panels. you will need at least 4 independent mppt inputs (might be able to do it with 3) because you have an odd number of each panel. Or don't use 2 panels, and you can get by with 2 mppt inputs.

I would suggest buying something like the eg4 18kpv, and get it permitted and PTO with the utility. The ability to export should pay for itself in a few years (vs the cost of a cheaper non exporting system).

When your AGM's fail, if you choose the Sol-Ark 15k instead, you may be able to buy LIFEPO4 batteries and take advantage of the Energy Storage Solutions subsidy in Connecticut. Currently, Sol-ARk 15k is approved for ESS program, whereas 18kpv is not.

Just an FYI I am buying 1 more of the 325 watt panels so I have a total of 16 the 275 watt panels I might use for something else such as my hot water heater with DC elements. would it be wise to buy 5 more 325watt panels to make it a total of 20 panels?

 

[thom72]

Just an FYI I am buying 1 more of the 325 watt panels so I have a total of 16 the 275 watt panels I might use for something else such as my hot water heater with DC elements. would it be wise to buy 5 more 325watt panels to make it a total of 20 panels?

I almost forgot, i am getting the panels from a guy in Woodstock CT for $50 a panel