diy solar

diy solar

Gate opener

MTMaloney

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Apr 17, 2021
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I got some solar panels from my daughter when they upgraded. These are 255w, 36v, 7a panels about 7 years old. They were going to pitch them so I took them. My first attempt at solar was to install an automatic gate at my farm. I bought a Mighty Mule single gate opener (571, I think). I connected one solar panel to a Renogy ROVER LI 40 AMP MPPT SOLAR CHARGE CONTROLLER. I output that to a 12v deep cycle flooded battery and connect the load to the controller. It is all wired together with 10awg strained wire.

Everything works well when the sun is out. However, when I get out to the farm in the morning before the sun is up, I have to push the clicker between 3 and 12 times to get the gate to open. The opener beeps when I push the clicker but for the first several times the gate doesn’t move. Then it finally opens.

The controller is set to use the battery whenever necessary, i.e., absence of sunlight. Everything seems to check out. The solar panel voltage is to spec. The controller says the battery is 100%. Btw: I have connected two other solar panels to a 24v system that runs a little heater for a while at night.

Any thoughts would be appreciated. —Mike Maloney, Cateechee SC
 
Did you bypass the small battery that is normally in the controller case? I think my solar cell for gate standalone is 5or10 watts and charges the internal battery. No ac to gate. Do you have enough parasitic load to kill the battery overnight?
 
...Everything works well when the sun is out. However, when I get out to the farm in the morning before the sun is up, I have to push the clicker between 3 and 12 times to get the gate to open. The opener beeps when I push the clicker but for the first several times the gate doesn’t move. Then it finally opens....
I'd check the connections, possibly when the sun is out it's hot and the metal expands making good contact. When it's cold, they loosen up and you get an iffy contact.
 
I have dealt with the MM571 before, it is a little finicky, but they have great telephone support.
most likely you have a config issue.
 
MM571 board requires 19V at the terminals (from either solar or the included 19V transformer/wall wart).

At 12V, your MPPT output won't charge batteries through the board if you've connected it there. It *might* operate the arm, it might not. (Sometimes it did for me, sometimes it didn't.) That's with the MPPT connected to the input terminals between the two fuses at the top left of the board. I think that's what you (OP) was seeing too.

I never tried connecting the MPPT directly to the battery input wires (the ones that are soldered to the MM571). I imagine that'd be stupid too (like everything else GTDO makes, added "D" for don't => gates that don't open). So if that's where you connected, what happened?
 
I didn't mention before-- my final solution was simply to take the MPPT output (off the solar panel) directly to the batteries (I have a pair of batteries in a really nice Ghost Controls battery box). That means the connection directly to the battery input wires inside the gate controller box would do the same thing. From what I could figure out, as long as those terminals don't float above 15v or so all is well. My panel is a Suner Power 30W cell- they're 100 bucks, way cheaper than the MM branded ones, and come with the MPPT for trickle charging 12v batteries.


Another solution I had was to use a boost voltage regulator to go from 12v to 19v off the solar panel/MPPT. They are readily available for <20 bucks on amazon (I went with an overkill size, 150w, cost about 25 brand is uxcell). This worked too, but frankly, it's inefficient (by how much, I don't know) compared to just charging the batteries directly from the MPPT- that's what most of the standalone solar cells you can buy on Amazon are designed for anyway, namely charging car batteries. The controller board doesn't care if it has power to those top terminals or not (that's what's happening at night, right?), so as long as the batteries are kept up above about 11.5v the MM571 will work just fine.

I did all of this because of the exit loop, the automatic gate lock, and the additional... other gadgets I have hooked up that are all powered by those batteries. I wanted to ensure the batteries can open the gate even if it's 5 degrees outside, so I got the bigger solar panel, and it snowballed from there....

As far as range goes for the MM571, there are lots of things you can do- the easiest is to simply go find a better antenna for the controller box. 20-30 bucks max. I did and now the range is at minimum 400 feet (distance from house to the gate, and through the walls of my house, too) using the 3-button remote. The single-button remotes don't seem to fare as well. The hardest thing you can do? Well it's kinda easy to find the wavelength spectrum the transmitter/board operates at, and.... a "little" harder to "build a better mousetrap" based on that wavelength, but not impossible ;)

One last comment: don't even bother with the hundred-dollar add-on to use your phone to open/close the gate from anywhere unless you purchase a wifi range extender and put the base for the thing somewhere within 100 feet of the gate. The link between the base and that wireless kerjigger you install inside the gate controller is very tenuous at best, I found anything further than 100 feet and it'll constantly drop; even worse is the wifi connection between the base and any router if there's anything in between the two (think must have line of sight!). I ended up just mounting the damn base right next to the gate controller box- and enclosing everything, including the battery box and boost regulator, in a waterproof/pestproof larger box mounted on a pole instead of hanging off the fence. I use a TP-Link CPE-510, gives me great wifi signal out there at the gate; the CPE510 is a great little repeater, it lives up in my attic pointed toward the gate. You can get fancy and use a Yagi but it's overkill- the CPE will do the trick on its own.
 
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