Any tips on my setup?

[J.P.M.]

To be clear, I'm not questioning his knowledge or ability, but he turns every single discussion into a shouting match. If I was building a $30k+ grid-tied system maybe I'd say "yes sir" and take my licks, but when I'm working on an RV installation it's completely ridiculous for him to go into pompous shouting mode and hurl insults. And furthermore in this discussion at least he hasn't contributed anything useful and has in fact gotten in the way of people who are, over and over again.

Here's what may be the crux of the problem: What if others are taking what you write and (perhaps ignorantly) running with it, and some others here who may be quite knowledgeable sincerely and honestly think what you are doing is wrong, wasteful and perhaps dangerous, but you remain adamant without convincing the knowledgeable naysayers with more convincing arguments ? What options do the naysayers then have ?

[Sunking]

Probably one of those pay as you go cell phone companies but I don't know if they have modem cards anymore. Some energy management hardware companies have "data monitors" that perform that task but it may actually be more expensive then a cell phone company.

No not the card, just a USB Modem. Both Verizon and ATT have what they call WiFi Hotspots. About the size of Altoid Mint can. It is 4G LTE/AWS/IOP. Set it in your house or wherever you want, then connect via WiFi. My cell phone can even do it as it is called a WiFi Bridge. Works just like the WiFi Hotspot, log in from your puter via WiFi and the phne makes the Bridge to LTE/AWS/IOP. Many Smart Phones can do it if you can afford the data bandwidth.

[Sunking]

I googled your previous username, from before you changed it on this forum, and found countless other postings all over the internet where you do nothing but hijack every thread and insult people under the guise of helping them. I found at least 4 other online communities that had basically kicked you out..

You are a liar. Prove it or shut up. Slander will get you banned real fast. So you had better prove it or you are toast.

[SunEagle]

I'm also wondering if anyone has any experience with cellular modem cards in the U.S.? I have internet when I'm there, but where I park it when I'm away I don't, and it would be nice to be able to access the data remotely, or at least have it upload every hour or so. That's not worth the $20/month that (I think) Verizon would charge me to add a line, but maybe someone has had some positive experience with metered cellular data in the U.S.?

Probably one of those pay as you go cell phone companies but I don't know if they have modem cards anymore. Some energy management hardware companies have "data monitors" that perform that task but it may actually be more expensive then a cell phone company.

[Wrybread]

I'm also wondering if anyone has any experience with cellular modem cards in the U.S.? I have internet when I'm there, but where I park it when I'm away I don't, and it would be nice to be able to access the data remotely, or at least have it upload every hour or so. That's not worth the $20/month that (I think) Verizon would charge me to add a line, but maybe someone has had some positive experience with metered cellular data in the U.S.?

[Wrybread]

That temperature sensor looks pretty good at +/- 0.5 degree C and not needing to be in contact with anything. Much better then some of the probes I use to use with my old fluke meter.

I'm a fan. Looks like you can daisy chain multiple probes on a single string too.

[SunEagle]

That temperature sensor looks pretty good at +/- 0.5 degree C and not needing to be in contact with anything. Much better then some of the probes I use to use with my old fluke meter.

[Wrybread]

Anyway, been working on my app some more. I won't be back to the RV until the weekend so I'm running it with simulator data, which is just random numbers, so the plotting is all over the place. I added a few pages. The first screen, showing battery watts in center and volts at top right, is unchanged. This one isn't simulator data, and is what it looked like last Saturday as the sun was coming up.



Swipe to the second screen, showing battery volts in middle and on the graph, and SoC at top right. This one is random simulator data so the plot is all over the place.



Next screen, showing fridge temp in middle and power source (solar or propane) at top right. Incidentally it was fantastically easy to rig up a temperature probe using one of these guys. IMG_2139.PNG


And all the data on one screen. The formatting and background image here aren't at all final, especially on this screen, I'm mostly just organizing the data at this point. IMG_2140.PNG


When I'm back on site I plan to add the other data points from the controller, like "temperature inside case", "heatsink temperature", max PV voltage, total energy generated today/this week/this month/ever, battery charge state, and whatever else looks interesting. I also plan to add a few other things that have nothing to do with the solar system, like the RV inside temperature and data from a weather station I'm working on.

As far as plotting the data, I'm saving an average of everything every 15 minutes to a local database, I registered for an account at pvoutput.org, and it looks like they expect an update every 5 minutes? sensij, are you uploading your data live, or do you log into their site and upload it manually?

And do you know what data you're uploading? Is it just PVAmps and PVVolts?

Having a look at their API it looks easy enough to just send them an update every 5 minutes, but from a quick look I'm not clear on what data they expect exactly.

[Wrybread]

And looks like the Morningstar 45A MPPT at the link Sunking posted is now up to $478.

[Wrybread]

To be clear, I'm not questioning his knowledge or ability, but he turns every single discussion into a shouting match. If I was building a $30k+ grid-tied system maybe I'd say "yes sir" and take my licks, but when I'm working on an RV installation it's completely ridiculous for him to go into pompous shouting mode and hurl insults. And furthermore in this discussion at least he hasn't contributed anything useful and has in fact gotten in the way of people who are, over and over again.

[J.P.M.]

Why is that? Why are you here hijacking this thread over and over and making sure it degenerates into bickering and insults even after being told it's uninvited?

I googled your previous username, from before you changed it on this forum, and found countless other postings all over the internet where you do nothing but hijack every thread and insult people under the guise of helping them. I found at least 4 other online communities that had basically kicked you out. I got a good chuckle when I stumbled on another posting where someone was recommending putting you on mute, just as I had recommended. You're absolutely toxic. In short, you're a troll.

There's lots of other threads on this board for you to hijack, and as I can see from your posting history today alone (congratulations on your 20,000th post by the way!) you're engaged in multiple other arguments on this site. And I'm sure many others all over the internet. I have a feeling I'm feeding the troll by saying all this, but please do us a favor and go harass someone else and turn off "subscribe" on this thread.

But I bet you've learned a few things since showing up here. That you're still here, in spite of all your apparently hurt feelings, may say something in the way of agreement that it hasn't been a total waste for you. Welcome to the forum of few(er) illusions.

With that in mind, having sniffed around some, and keeping in mind my limited knowledge, I'd also suggest this place is a fair amount more technical, and technically sophisticated and correct (read MORE SAFE) than some other places you can ask questions.

FWIW, while SK appears to suffer fools less well than some of the rest of us, my suspicion is he's one of the more tolerant - at least compared to what he might want to write - but has a more acerbic and direct style that some snowflakes can get in sync with. But that's conjecture on my part and NOMB anyway. 20,000 posts as you note and, by may anecdotal recollection, maybe 3 or 4 pissed off posters /yr. doesn't seem too bad. Making omelets all the time will result in a few broken eggs 1X/a while.

It may be that part of the problem you seem to want to foist on others is that your skin is a bit thin. There seems a lot of that going around these days. Anyway, you can always ignore what anyone writes. Or, accept some parts of what anyone writes and ignore the rest. There is also an ignore feature. Some things you need to do for yourself. The mods and admin. are not your mother.

From what I've seen of your output on this and other threads, if I was looking for answers or opinions about one of the many aspects of solar electricity I'm clueless and ignorant about, and had a choice between taking your stuff seriously or SK's, there would be little choice in my mind. See my 03/07/17, 12:08 P.M. post to this thread for particulars as to why.

Take what you want of the above. Scrap the rest.

[sensij]

I stumbled on another thread where someone was recommending putting you on mute, just as I had recommended.

Try to imagine if your first exposure to Sunking had been in this thread:

https://www.solarpaneltalk.com/forum/off-grid-solar/off-grid-solar-panel-systems/344573-does-my-mppt-scc-and-120v-charger-choice-make-sense-for-my-lifemnpo4-batteries/

I don't think that painting his contributions in the broad strokes you've stated here is really very fair. If I was running the forum I would struggle with determining at what point the bad outweighs the good, but if the post counter kept track of only "good" submissions, he'd still have a higher count than anyone else.

.

[sensij]

Where is that missing 140 watts going? It has to go somewhere in the form of waste heat. .

It goes into the solar panels, as irradiance that is not converted to electricity. The MPPT function remains intact even as the controller moves off of the maximum power point; it just tracks a target that is not maximum, becoming a constant power controller by riding along the IV curve as needed to stay within the controller's output current limit. PV current drops fast as V approaches Voc, so the charge controller never gets more than the 520 W (for example) of power it can handle.

You can make an argument that operating at rated current for more time out of the day is bad for the controller, but that is a different conversation. If the alternative is to replace the controller anyway, why not let it ride, as long as the other appropriate safety measures are in place? Under the conditions discussed in this thread, it isn't going to handle max power for very significant periods of time anyway, limited by either the availability of the sun, or the transition to absorb because battery voltage has hit setpoint. (although OP's plan to add in opportunity loads changes the workload a bit).

Edit:
What I wrote above applies only to the bulk stage. In absorb or float, the controller will clearly move away from the maximum point in any case. If it transitions to straight through PWM control, in the most basic form, it rapidly connects and disconnects the array from the battery as needed to maintain the desired voltage. During the connected time, it is in the constant current segment of the IV curve (PV voltage = Battery voltage < Vmp), and you count on the PWM logic to prevent excessive power from being fed to the battery.

For this controller, the manual states:

WARNING
Controller will be damaged when the PV array straight polarity and the actual operation power of the PV array is three times greater than the rated charge power

So really, putting 900 W on it is well within their 1560 W damage limit.

I would guess that the most dangerous scenario is in bulk at noon on a cool, mostly clear day, but with dynamic partial shade or cloud reflections that scramble the mppt logic. Pages 4 and 5 talk about it a bit, but by tracking the min and max PV voltage and current at some higher sample rate (not sure how fast the RS-485 output updates), along with the 15 min interval the OP suggested, it might be possible to evaluate how well the mppt and other regulation routines are performing. If the observed voltage and current ranges are narrow in each 15 minute interval, that would be a sign it is handling the conditions properly.

[Wrybread]

Sunking, I respectfully ask you to not hijack this thread again. We'll somehow manage without your input.

[Sunking]

Then, as in this thread, I was advocating for increasing the PV capacity beyond what the conventional "panel STC rating / battery voltage = charge current" calculation would suggest.

Sensij you are a sharp guy and should have a good working knowledge of MPPT controllers and panels.

So what does the controller do when you over power it? Stop and think about this.

Two things happen.

1. The controller no longer operates as MPPT. It behaves like a series voltage regulator where it input current = output current right?
2. The solar panel no longer is a Current Source and turns into a Voltage source like a battery right?

Now stop and think what that means. We know if the panel is operating as a Voltage Source the voltage is greater than Vmp operating some where Voc and Vmp right? 72 cell panel Vmp is roughly 36 volts and Voc = around 46 volts right?

So lets just say conditions are the panels paralleled up together are sending 10 amps of current to a 12 volt system. Battery may or may not be charging. Could be the equipment drawing al the power.

As I said the controler is not operating in Vmp or boost mode, just a plain ole series regulator. So the panels are say pumping 38 volts at 10 amps (380 watts) into the controller. On the output of the Controller we know is outputting 10 amps at battery voltage of say 14 volts (140 watts).

Where is that missing 140 watts going? It has to go somewhere in the form of waste heat. .