Hello.
My Classics have been running for 10 years now, and I haven't regretted it. That's worth mentioning, since people are usually quick to complain (and I'm no exception to that, unfortunately).
A lot has happened in the 10 years and since my last visit here. The link to my PV setup is still valid (http://a68k.de/pv/ — and I've continued the documentation in a dedicated playlist on my YouTube channel, @a68k_de).
The reason I'm writing today...
I noticed today that the "East" Classic is running at almost full power (~50 of max. 79 Amps) , while the "South" Classic is contributing only a minimal amount—just a few amps.
The Junior is connected to the "South" Classic.
I have no "follow me" ... I can't remember why, but there wa ssomething not working as expected ... sorry ... braincellrott :D
The "Local Status Panel" (I assume there isn't a newer version or alternative?) shows the "Current Limit Reached" icon for the "South" Classic.
However, the maximum current hasn't actually been reached yet, which is new to me.
Here's what changed in my system this year:
East: New modules—"9 x Trina Vertex S+ 455W Glass-Glass Black (TSM-NEG9R.28)"—arranged in 3 strings of 3 modules each. This is working excellently.
South: Previously, just like it was on the East, there were 3 strings of 4 modules (240 Wp). Now I added a 5th module to each string here (using the old ones left over from the "East"). In the process, I discovered a defective module on the "South" and replaced it with a working one from the "East".
I took a look at the charge controllers and suspected the "Turbo Fan"—a part I've had to replace before. They are still noisy due to their high RPM, but then I remembered that they've been running all day for quite some time now...
I've attached a picture to show which fans I mean
The bottom fans on the "South" unit aren't spinning at all, and only one of the "East" unit's fans is turning.
I'm assuming the answer is "yes," but before I shut down the system tonight to take the Classics apart and get to the fans—the fans should definitely always be spinning, right?
I've left the front covers unscrewed for the time being to allow for better heat exchange with the ambient air, and I'm continuing to monitor the alert.
Right now (3:20 PM), the "East" unit is still delivering 2,300 watts at 42 amps, while the "South" unit continues to report a current limit. The "South" unit briefly spikes to over 1,300 and 1,500 watts, then drops to below 1,300 watts.
I just want to be on the safe side ;-)
Sorry for the long message; it was important for me to provide as much information as possible.
Thanks in advance ;-)
I can see the fan in the photo looks like it has a fair amount of dust on the blades. If it is loud maybe try cleaning that off using a small pipe brush.
I always thought the turbo fan was at the top ?
But I have never messed around with the fans on my Classics and don't think I ever heard them run unless they were moving a lot of amps.
There are some topics about fans and how to test them here
https://www.midnitesolar.com/faqList.php?faqCat_ID=57&faqCatName=Classic%20Charge%20Controller&parent_ID=2&subCatName=Troubleshooting
Larry
Thanks ;)
regarding the bottom fans on one "Classic" model, only one of the two actually runs, while the other doesn't work at all. Yes, there is dust on the fan blades. I can spin the fans with my finger, so it seems the electronic inside the fan itself has failed.
And if you look at it this way: they had to work hard for the last ten years. That's not something you take for granted these days, either :)
I just watched an old video showing that the fans can be replaced from the back. It's been so long that I'd completely forgotten about that. That really simplifies things.
(please never delete these videos!)
The "Turbo" fans are just louder than the originals because the old ones were broken, and these replacements have a higher airflow rate :)
While I was just in the basement, I noticed the one working fan is still spinning; the sound triggered a memory (sometimes it's funny little things like that that bring memories back) of how the bottom fans used to keep running for a long time in the evening. I've ordered new fans now and hope they arrive quickly.
In the meantime, this "forced ventilation" setup will have to do the job ;-) (Photo attached. It's controlled by an AVM smart plug and helps with cooling for now.)
On both my classic 250's I drilled out a grid of 1/4 inch holes on the bottom cover. It lets in a lot more air and I only hear the main fans on a large current input, the turbo fan, never.
The reason for the drilling is that there was no more holes in the controller to let air in. All taken up with conduit entering.
Yes, that's the downside of having to route the cables through pipes; unfortunately, it blocks the openings.
The new fans arrived today (https://www.ebay.de/itm/271649506635 and https://www.ebay.de/itm/312202792195)—I ordered four of each. I know Murphy ('s Law) all too well, and I needed the fans ASAP. They have good airflow. Even though the listings advertised different specs, I ended up receiving the exact same fans in both cases ;-)
I've installed them now before I had too leave for work. In the "South Classic" unit—where no fan was spinning before—they still aren't spinning, but the turbo fan.
I'll keep an eye on it and I'll perform a "reboot" on both Classic units tonight when I get home from work. The fans should all spin briefly during that process.
I tested the new fans on a lab power supply first; they're fine. As for the removed fans—aside from the one that was still working—the other three are dead.
In case the fan control in the "South Classic" unit is broken, I'll just wire the new fans to an unused AUX port and have them run whenever energy is being converted. (I need to review the options again; I can run them directly off that... 12 volts.)
Aaaand they're very dusty. But I'll deal with that in the winter when there's no energy to produce. I'll shut everything down, take the Classics apart, and give them a proper cleaning. They'll hold up until then.
I rebooted both Classic. The South Classic did well, all fans spon.
In the East Classic only the turbo fan spon, the both inside not.
So I guess the controller is gone ... I wired these fans to the AUX1 and set this AUX to "Daylight". manually turned on, fans spinning.
In my opiniont it doesn't hurt, if they run the whole day.
Later this year in wintertime when I clean them I will have a closer look to the boards if there is something visible and I can compare both Classics boards.
I noticed today that the "South" Classic is getting very hot again and it is current limiting.
The fans are running; I can feel the hot air exhausting.
I might need to install an external fan, as shown here: https://midniteftp.com/forum/index.php?topic=9823.0
Maybe an extremely powerful fan that forces air into the side opening.
Thanks to 3D printing, everything can be adapted ;-)
Or, if I had any of those case front panels lying around, I could cut open the lower section and mount a powerful fan right there on the front.
Are there any 3D print files (.stl) for the case, or something similar? :D
Luis just posted something the other day
https://midniteftp.com/forum/index.php?topic=9823.0
larry
Some experiments with fan adapters ;-)
The neck on the first version is too short; it hits the metal plate behind the "lassic unit in my setup ;( I've created an extension for it, which is printing right now.
Then there's another version with a longer funnel (I'll print that one later while I'm at work) to test out.
The version with the 90° bend is currently just an idea for the "East" Classic, as I have very little space next to it.
There is also a version with an offset funnel; I still need to test whether that fits.
After that, I'd be happy to make the print files available—I'm sure others could use something like this, too.
I had some spare fans lying around. This 60x60mm one is a left over from servicing the digital projector in my cinema - they have to be replaced regularly but still work perfectly.
3 more pictures
short update ...
It really seems to work; the temperature has stabilized.
It's crazy how much heat is being blown out of the top of the case :)
We're having rain now ... - I'll keep monitoring the situation over the coming hot days. I'm also making a few final improvements to the 3D models.
You might think about putting a little foam filter on the fan. I've seen how much dust gets caught in one when it runs continuously. Not the best stuff to cover electronics with.
Thanks; yes, I still need to give that some thought ;)
Even though I've got the temperatures under control now, I'm still seeing the "current limit" today...
Currently:
East: 30.30 Amps, South: 2.3 Amps... combined 32.60 Amps
Charging current is then 71.30 Amps
The WBJr shunt is connected only to the South charge controller. The maximum setting there is 78 Amps in the "App" - which is likely my problem?
I've now set AUX2 on the South Classic to something else for testing purposes; the South Classic shouldn't be measuring current anymore.
(I'm missing that value in my visual display now, but it's fine for testing)
Now (12:15 PM)
East: 21.8A
South: 15.29A
Total: 37.60A
Charging current: 80.40A
Fluctuating, and clouds are rolling in. Great...
The day before yesterday, I briefly had a charging current of 107 Amps—so I'm not entirely sure if the WBJr shunt is the limiting factor here...
But with the WBJr inactive, the current on the South side went up nicely.
Where am I going wrong (again...)?
Surely we can use the WBJr to get the reading without it throttling the charge controller?