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 The Solar Wind Grid Tie Inverter GTI Controller
Sell Your Excess Energy To The Grid!
Simple, easy way to send excess energy to the grid
and keep your batteries charged

  • Save Money - Reduced grid power usage saves you hundreds every year!
  • Works With A Charge Controller - Low cost charge controllers are OK too
  • Wind, Solar, Hydro - Why not? Just needs batteries
  • Run 300W GTIs At 24V - Higher voltages = less wire loss & better performance
  • User Adjustable Set Voltage - Set it to come on at a voltage you pick
  • Battery Has Priority - The battery has priority first thing for less sulfation
  • Battery Is Always Ready - The battery stays charged, ready for a grid failure
  • OK On Cloudy Days - Automatically adjusts to all solar conditions
  • Up To Two 300W GTIs Or One 600W GTI - Grow your system
  • No Float - Why float the batteries and also pay the power company?
  • CPU Controlled - Microprocessor controlled for set point and timing
  • 48V Too - Using the right GTI you can go up to 48V (adjustable)
  • Easy Install - Two wires in and two wires out!
  • Eco Friendly - Reduced CO2 emissions! Reduce your carbon footprint!
  • Home Value - You own the solar panels, not the power company!
  • Made in the USA - Designed and manufactured in the USA

"Smart" Meters will charge you for power both ways so you need to know the situation where you live.

These are custom order units! Please contact us.

If you already have solar panels or a wind turbine and batteries, what happens when the batteries are fully charged? Your charge controller goes into float mode and all that solar or wind energy goes to waste.

Why not pump that extra solar or wind energy into the grid?

The GTI Controller allows you to grid tie your solar panels and also keep a set of batteries charged for power outages and emergencies.

pic GTI controller wiring
Simple operation: The special programmed CPU switches up to two low cost 300W Power Jacks, Suns, or other small Grid Tie Inverters (GTI) at a set voltage (typically set to 28.8V) for 2 minutes, allowing it to ramp up, then turns it off and waits for the voltage to come up again.

Keeps the batteries charged and ready for emergencies, but any excess goes to the grid!

Works with wind turbines, solar or hydro using a 24V-48V battery bank.

Learn more and see it in operation in this YouTube video:


A normal GTI would pull a 24V battery bank down to 14V if you connect it directly without the controller. Each run is only 2 minutes, not enough to take much charge from the batteries. Then if solar power is enough, it trips again and again.

pic solar wind GTI controller Later in the afternoon, solar power starts to go down and the voltage doesn't trip the GTI anymore, but your batteries get a nice "topping" charge just below 28.8V for a few more hours.

User adjustable voltage set point. The CPU takes care of the GTI on/off timing.

The battery has priority first thing in the morning for less sulfation due to overnight low battery charge. Batteries have a internal resistance so even if they are not used they run down a little overnight and should be brought back up to charge as soon as possible, the GTI Controller design does this automatically. Batteries have a limited number of deep cycles so to extend their lifetime it's good to keep them topped off all the time.

Questions? Take a look at our extensive and long winded GTI Controller FAQ page.

Batteries suck! They are messy, need water, maintenance, and have a limited lifetime of around 5 years so you want to reduse how many you have sitting around if you also have the grid available. Use the grid when possible but be ready for power outages for as low cost as possible.

Runs the "14V" GTI at higher voltages (typically above 24V) for less wire loss and better performance. A typical low cost 300W Power Jack, Sun, or other small GTI runs from 14V to 28V as spec'ed, but will start up with voltages just under 30V typically which allows room for a normal charge on a 24V battery bank.

Cloudy or partly cloudy days are not a problem, the battery always has priority and the GTI Controller automatically adjusts to all solar conditions.

Can handle up to two 300W GTIs or one 600W GTI depending on your solar input wattage, generally up to 400W of solar would be good with one 300W GTI and two 100 Ah to 125 Ah 12V batteries. Wire type and length are other factors to consider.

People have tried connecting a GTI and charge controller in parallel, but they fight each other, the battery does NOT get priority first thing in the morning, and on cloudy days the GTI takes everything. You can try to manage that manually if you want.

What happens if the grid goes down? You have battery power! The GTI won't come on so the charge controller will keep the batteries from over charging and of course you can power whatever you need from the batteries.

Questions? Take a look at our extensive and long winded GTI Controller FAQ page.

pic Eaton disconnect box Fits in this recommended Eaton low cost UL Listed electrical disconnect box available at Lowes or Home Depot (not included). You get a disconnect switch, wire connection terminals and a nice enclosure with no extra shipping charges!

No moving parts (such as a fan), it works quietly and efficiently day in and day out without maintenance hassles.

This device comes as a partly assembled kit. The circuit is fully assembled and tested and comes mounted on it's metal heat sink which is designed to fit perfectly in the Eaton box.

Buy a Eaton box from Lowes, Home Depot or a local Electrical Supply house, buy some plywood, mount it & wire the unit. No soldering required.

A 30A ATC Fuse and Fuse Holder are included.

The Eaton box and plywood are not included in the kit.

The GTI Controller will also switch a Modified or Pure Sine Wave AC Inverter on and off. Examples would be pumping water up hill into a tank or running a well insulated freezer with lots of freezer packs inside to keep it cool at night. Use your imagination! Anything that can be switched on and off but still save you on your power bill. Your AC load should be 500W maximum (around 25A max), and using a small 750W or less inverter.

You will now own something of substance and value instead of throwing money year after year into the power company black hole!

Reduce your carbon footprint now! Reduce reliance on foreign oil!

pic American flag The GTI Controller is made in America! Your purchase helps support local American electronic assemblers, parts suppliers and machinists.

A Few Customer Reviews And Installs:


"It's working great for me, it's topping off my batteries and it's making full wattage ... I love it ... It charged them up first thing this morning after I ran them all the way down last night"
Scott, OK   (Youtube video)
(470W of panels 2 x 235W, 100 Ah total batteries, 22V-50V 600W Power Jack GTI)


"It appears to be running a lot more efficient than when I had it at 12V" (now at 24V)
Willy, NY   (Youtube video)
(200W of panels 2 x 100W, 110 Ah total batteries, 10.8V-30V 300W Sun GTI)

http://www.youtube.com/watch?v=UQbQAvRxJu0 (part 2)

"Good job, works great... cost effective and easy way to do this..."
rhandsom, AL   (Youtube videos)

These are custom order units! Please contact us.

Suggested List Price: $299.95 (without box)

Please contact us at :

E-mail: nrodge at techluck dot com

Or use the [ Contact Form - click here ]

Thank you for your business!!

Unusual orders, custom designs or special needs, please Contact Us.

Dealer or Installer inquires are welcome.

Absolute Maximum Voltage: 65V DC
Absolute Maximum Current: 30A (one 300W GTI is about 13A @ 23V)
Typical Operating Current: 25A with 2 x 300W GTIs and 24V batteries
Minimum Voltage: 8V DC (10.8V type GTIs, 12V battery, not best but works, see FAQ)
Included Fuse: 30A ATC with fuse holder
Microprocessor CPU Controlled
Insertion Efficiency: 97% (pass through)
Switch: High tech, latest technology high amp MOSFET (over designed)
MOSFET Gate Drive: 15V, hard off/on for maximum efficiency and quick switching
NEC Article 409 compliant when using the Eaton UL Listed, NEMA 3R enclosure
Recommended Batteries: 50 Ah or larger each 12V battery, 24V to 48V set
Recommended GTIs:
Up to 2 Power Jack 300W (newer and older models), Sun 250W (14V to 28V spec input types) or one Power Jack 600W (newer and older models), Sun 550W (14V to 28V spec input types or with a little less efficiency the 22V to 50V types), Enphase or up to 600W any kind that can run well in the 24V DC range.
48V systems can go higher wattage, typical amps stay at 25A.
Remember, a GTI connected to a battery will go full output, around 240W for a "300W" GTI
Recommended AC Inverters (if switched by the GTI Controller):
Modified or Pure Sine Wave up to 750W (24V type) but you need to keep your load to 500W or about 25A MAX and will be switched on and off so the inverter needs to come on automatically (again see the FAQ).
Load Type: Resistive loads only (no reactive loads like motors or anything with big coils)
Wire Size: 10 AWG minimum, 5 ft max length to/from box/batteries, shorter is better
Controller Size: 4.5"W x 4.5"L x 1.5"H
For indoor use only.
Must be mounted in a Eaton box or other larger box/piece of metal for a heat sink.
Eaton box gets slightly warm at full rated power.
These specifications are subject to change without notice.

This is a low voltage DC off grid device not connected to the electrical grid "mains"

Eaton Disconnect Box: (buy it at Home Depot, purchased separately)
Note: Controller fits in this exact box perfectly without any modifications
60 Amp Non-Fusible Pull Disconnect Model: DPU222RP
UL Listed: 74X2 #E132354, #E143893, #E196365
CSA Listed: File 069743 (DH222R)
ANSI certified
NEMA Rating: 3R Enclosure
Suitable for CSA Type 3R applications
Meets 2008 NEC Article 422.31 (B) requirements for servicing electric water heaters
Copper or Aluminum wire rated (AL or CU Wire)
Canada Alternate Model: 3GAC222NF
Box Depth (in.) 3 in
Box Height (in.) 9 in
Box Width (in.) 5.5 in
Do not buy the GE box that looks the same, it's too small inside and the controller won't fit.


Lots of ways to use this device, use your imagination!

Say you want to take a refrigerator off grid. A refrigerator cycles on and off, so it may be possible to run the GTI during the off periods (depending on solar panel size and refrigerator size of course).

You can use a normal standard DC to AC inverter with the GTI Controller no problem, the inverter connects to the batteries as normal.

If the battery needs charging then the GTI doesn't come on, but when the batteries are charged up, the extra goes to the grid.

Now let's say the refrigerator turns on. This lowers the voltage of the batteries and keeps the GTI off until the fridge turns off and the batteries come back up to charge.

What happens if the grid goes down? You have battery power! The GTI won't come on so the charge controller will keep the batteries from over charging and the fridge continues to run off the solar panels and batteries as normal. Any extra power goes to other loads you may want to connect to the inverter while the grid is down or the extra power simply goes to waste because the grid is down.

You save money running the fridge off grid and save even more money pumping power back into the grid!

The batteries stay near charge all day so you are still ready for grid power outages.

The CMP 12/24 Charge Controllers in the video are slightly modified with a small heat sink added since it was found that the mosfets could handle more current, the traces were also beefed up, see the post on the TechLuck forum about them. They are simple charge controllers found on eBay for a very low cost.

The fans shown in the video were actually old PC power supplies cut up so you can use just the fans, see the Youtube video about how they were made.

Questions? Take a look at our extensive and long winded GTI Controller FAQ page.

The GTI Controller is Patent Applied for.

Some TV people are calling Solar Panels a Solar Generator, watch out for the low power, over priced "as seen on TV" systems out there. Solar Panels are currently available for $1 a watt shipped to your door, look around!

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Need professional Telephone System Message On Hold? Dependable, highly recommended!

Forum Thread Index


Solar Hot Water Controller
pic solar hot water controller
· Solar hot water the easy way, no plumbing

Charge Controller Fixer
pic solar-charge-controller-fixer
· Fix that stuck on low voltage panel side Solar Charge Controller!

Solar Spa Heating System
pic solar hot water spa project
· Solar Spa / Hot Tub Heating System MPPT PV DIY Project

GTI Controller
pic solar hot water controller
· Keeps your batteries charged any extra goes to a Grid Tie Inverter
· Run a 600W GTI at higher voltages for less wire loss and better performance

Wind Turbine PWM Dump Load Controller
· Keeps your wind turbine within set limits without wasting power


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