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Dennis Mono wrote:
David Baillie wrote:
All the research I have seen claims a 30 percent increase for dual axle trackers. They have lost favour here due to their high maintenance requirements.
I do live at 45 degrees so that is a huge ark in summer and challenging temperatures swings in the winter so it pushes the mechanisms hard. If you are the type of person who can change a control board, a dead sensor and an actuator you stand to gain some production. If you have to call in a technician every time a component acts up then no. For my thinking A good portion can be made up with a manual seasonally adjusted array angle. For the rest add panels which are cheap and do not require any maintenance. Installed once and maintenance free (or virtually) operation for its life span. Its a case by case thing though.
Cheers, David B.
The most Common problems we have encountered with Old designed Dual Axis Tracking (DAT) systems in Australia are;
1) Cheap Linear Actuators fail at around 10 years, these were mostly 12V Actuators, that did not have an External Motor &/or used Plastic Gears !
Solution: Use 24V Double Slew Drives, as these will commonly outlast your lifespan, as they move slowly, and will Not wear out the internal metal Gears.
2) The other Common Failure is the DAT Controller that use Relays may/will Fail at around 4 years, Relays can burnout & either Not work, or get locked on & damage the Racking or wiring.
Solution: Use a Controller that uses Automotive Mosfets, these are superior to cheaper Relays.
3) Many old DAT units did Not use an Anemometer (Wind Sensor) , that automatically Lays the Racking Horizontal (Flat), to avoid Damage to the Racking & solar panels !
Solution: Fit either a Digital or Analogue Wind sensor.
4) Analogue Stop Sensors can Fail like Relays, especially if Not Water proof !
Solution: Fit Magnetic Stop Sensors, and Silicon over the connectors, to better weatherproof the switches.
5) GPS or Time Tracking is Inferior to Radiation (Light) Tracking !
Solution: Purchase a 4 Direction Light sensor that uses 4 miniature solar Cells, NOT the LED light sensors, as they are inferior when it comes to Accuracy.
That pretty well cover what to avoid when purchasing a DAT unit.
We have only found One Hi-Quality DART Controller, it is a Polish Made REI DART Controller.
https://www.micropowergrids.com.au/_Wiring_and_Equipment/DART_Controllers/_Light_Sensor_DART_Controller_Module_type-1.html
Dennis Mono wrote:All this conversation is missing one important point;
If the Solar Panels are NOT perpendicular to the Sun, you are loosing up to 60% of the Energy you could be Generating per year !
To Generate 60% more energy per Year, you simply install a Dual Axis-solar Radiation Tracker (DART), that follows the Sun from as earl as 5:30AM to 8:00PM, depending on your Latitude.
Where the Further South or North of the Equator, a DART unit Generates Energy for a longer time.
NB: Radiation Tracking is Superior that either GPS or Time Tracking, as in Cloudy periods, points the solar panels to Dark Clouds covering the Sun, whilst Radiation Tracking will rotate the solar panels to the Brightest area of the Sky.
Yes, DART units have a Higher upfront Cost, however, the Additional Energy is Generated using approx. Half the Solar panels for the next 30+ years.
DART units are commonly mounted on a Pole, buried in the Ground, and have a wind sensor to lay the Racking Horizontal in Hi-winds.
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If purchasing Bi-facial solar panels, make sure they are Double Glazed, as they are not only Stronger, they also dissipate Heat better.
And for those wanting to Generate as much Energy as Possible from the Rear of the solar panels, you can cover the ground with White Stones or anything that is a White or Silver material, as that in a perfect situation will Generate up to 30% more Energy from the reflections.
hi Hannah, if by "at source" you mean at the solar panel that is how it is usually done. The solar panel puts out roughly 28-40 volts depending on size as dc voltage. The micro inverter converts it to 240 volts Ac (in North America). So you have between 1/8th to 1/6th of the power loss if you were to bring that dc voltage to the house. Those losses add up with higher amperage as well. The pattern now is to create high voltage dc strings of 280-500 volts and send that to a larger charge controller to convert to ac... Now with the Dc voltage being higher than the final AC voltage the line losses are lower keeping it as DC. It depends on the situation. If all you are doing is net metering to the grid and all you have is your roof then Micro inverters still make sense. When you involve batteries you are almost always better of using a string inverter. I almost never put arrays on roofs here since the roof angle is wrong for winter and snow clearing is much harder so its been years since ive specked a micro inverter setup.Hannah Garcia wrote:Bringing this one back up because I'm curious if anyone has tried using microinverters at the panel site for this setup. They might offer a decent solution by converting DC to AC right at the source and could make the longer distance transmission safer and more efficient. Plus, it could allow for system flexibility by working with lower voltage DC. Thoughts?
Yup, It's high school math. His reasoning for why we use larger cables is also dead wrong. We don't use thicker cables to carry the amps in this case we do it to reduce voltage loss to a low enough percentage to pass an inspection. Here it is under 2 percent some places in the States its 3 percent I'm told. If he had used the 12 gauge he was commenting about he would have been way over that over 400 ft.R Scott wrote:Because the “algorithm” rewards yellow journalism.
Douglas, for the longest time you could just spec out a magnum inverter a midnite solar charge controller and 3-5kW of solar and go home. Then China decided to push solar hard. Its impossible to overstate how completely they now own the industry. Cheap lithium options, panels and incredibly powerful inverters have turned everything upside down and halved prices... Solar arrays are now huge, lithium batteries last for 20 years the sky is the limit. Unfortunately there is also a proliferation of low end junk as well. Its now the wild west. I'm fairly conservative in my design choices sticking to companies with a North American presence for support.Douglas Alpenstock wrote:Wow, I'm shocked to discover I'm waaaay behind when it comes to the current state of solar. Thanks for the updates guys!
John Weiland wrote:
David Baillie wrote:.............The transformation happens at the inverter mounted near the end user. You should plan on a good steel jacketed teck cable and metal junction boxes or trays all the way to the inverter to minimize risk. Use a high voltage rated isolation switch at the array and high voltage rated Breakers at the inverter. It costs money but saves money in wiring and allows for much larger systems. It boils down to size of system, how far out you are and the level of loss you are willing to take.
David B., Does this suggest that micro-inverters installed within each panel are going by the wayside now for the industry at large? If I'm thinking about this right, micro-inverters would kick the DC voltage from the PV panels into 120VAC (yes?), which would reduce line loss (correct?) and possibly allow for less expensive cabling from panel to destination, although best not to skimp on that with any wiring exposed to the elements. For battery charging, this would need to be converted back to DC at the destination point. But I thought one advantage of micro-inverters was being able to grid-interie without an inverter positioned near the end-user. Thanks....
Bob Nall wrote:I'm curious if anyone has solar panels in a field approx 200+ feet away from their home. What is the preferred method for transferring power to the home inverter and batteries? Has anyone experimented with voltage drop at those distances? I was recently watching a youtube video on a water generator and he said something interesting, "if transferring power at the same voltage, DC is actually more efficient than AC." This goes against what many of us believe but it seems there is some truth to it. So it seems the higher the DC voltage I can transmit it at the more efficient it will be and I will also not have the restriction of eddy currents as I would in AC. Has anyone ran high voltage solar DC wiring at length? I am able to input 2 165V DV inputs into my unit, but I also understand at this point the DC voltage is getting to a "not safe" point. Obviously roof mount is an option but requires a lot more code and inspection processes.
Rachel Michelle wrote:
tony uljee wrote:clear plastic sheeting --as from polytunnel material--its uv treated --transmits 80 percent or more of light--and use the clear repair tape to hold it down around the framework----would be the cheapest ---next would be the specialist sticky back stuff applied to windows turns them into safety glass
I like the simplicity of that! But would condensation be an issue?
if they are not lithium its a vented to the outside box with a powered fan. Must be in a dedicated mechanical room, must have a smoke detector, must have a headroom of 6'9". Most of those apply to lithium as well except the venting and box.Allen Jackson wrote:Out of curiosity David, what if they aren't "lithium" batteries?