Solar (Temporary) Installation Progress

ALL NEW - Battery Finder Search for 12/24/36/48v or by capacity www.batteryfinder.net

Another quick update. One of the panels I hadn't installed yet turned out to be really good outputs after having cleaned the connectors. I was getting about 30Voc and almost 6Ioc, which is on par with most of the other panels already in the string.
So I hoofed it up onto the roof and added it to the string. So now I have 12s of the panels.

Oh boy was I surprised by the output!! I was getting about 225-250W output from the existing string. When I put that "one" panel up there, production increased to peaking over 500W periodically throughout the day!!!!

1724628089836.png


Just a single panel made a HUGE difference in power production! I was pleasantly surprised for sure!

I have 2 more panels that I can add to the list that have good voltage, but unfortunately they got cracked and now produce half the current. But I'll connect them in parallel with each other and then connect that in series with the existing string. As far as sealing the panels, I'm using Rustoleum clear coat sealant. Saw a video where a guy did that to his panel that got cracked and 2years later he says it's still outputting the same power and zero yellowing. I figured it wouldn't hurt to try.
 
Just noticed something is goofy with that graph. Here's today's graph from the inverter:
1724628411669.png


Voltage is pretty steady around 125-200V, but wattage is spiking over 500W. And today was cloudy on/off all day

I'll have to revisit the spreadsheet and see why it's off kilter.
 
Korishan said:
Another quick update. One of the panels I hadn't installed yet turned out to be really good outputs after having cleaned the connectors. I was getting about 30Voc and almost 6Ioc, which is on par with most of the other panels already in the string.
So I hoofed it up onto the roof and added it to the string. So now I have 12s of the panels.

Oh boy was I surprised by the output!! I was getting about 225-250W output from the existing string. When I put that "one" panel up there, production increased to peaking over 500W periodically throughout the day!!!!

View attachment 32320

Just a single panel made a HUGE difference in power production! I was pleasantly surprised for sure!

I have 2 more panels that I can add to the list that have good voltage, but unfortunately they got cracked and now produce half the current. But I'll connect them in parallel with each other and then connect that in series with the existing string. As far as sealing the panels, I'm using Rustoleum clear coat sealant. Saw a video where a guy did that to his panel that got cracked and 2years later he says it's still outputting the same power and zero yellowing. I figured it wouldn't hurt to try.
Click to expand...
Why do think 'just 1' more panel made such a difference... I would have expected a proportionate increase in PV but not double.
 
OffGridInTheCity said:
Why do think 'just 1' more panel made such a difference... I would have expected a proportionate increase in PV but not double.
Click to expand...
I'm wondering if it had to do with pushing the voltage slightly higher that allowed for better MPPT control. That's the only thing I can think of. Maybe another way to think of it would be similar to the way ADC's work. A 10-bit ADC will have a lot more jitter bouncing back and forth over some value whereas a 14-bit ADC will be far more accurate and smoother in the selecting. Perhaps with this the higher voltage allowed for a finer granularity of values to work with for the MPPT to choose from.
Kind of interesting overall. But I have no real idea why tho
 
man, this is weird. I'm redoing the panels and replacing the connector m4's. I also got an Elejoy EL400B solar tester (AveRage Joe uses this same model). When I go and do a retest of the panels, some are coming back not producing much current. I had one of them I connected and powered up the unit, and when it tried to do the mppt test, the unit shut down because the panel couldn't handle the current output.


but these were the exact same panels that were in production the whole time 🤔


I wonder if that could of been part of the jitteriness of the graphs, a panel, or more, was basically shutting down for a few seconds/minutes until the connection "repaired" itself and resumed production ????

I thought maybe I had bad connection between the tester and connectors, so I took some non-crimped terminals and inserted into the ends of the panel connectors and used the alligator clips to those, and still got the same results.

Anyone have some ideas about this?
 
Last edited:
Korishan said:
Anyone have some ideas about this?
Click to expand...
Just on the off chance..... one time I was freaking out that my PV production was way low and starting checking everything but actually the charge controllers were in Float because the battery was nearly full. Any chance the charge controller is not in full 'bulk mppt' charge mode (pulling max PV) for some reason?
 
OffGridInTheCity said:
Just on the off chance..... one time I was freaking out that my PV production was way low and starting checking everything but actually the charge controllers were in Float because the battery was nearly full. Any chance the charge controller is not in full 'bulk mppt' charge mode (pulling max PV) for some reason?
Click to expand...
Nah, my settings are for Hybrid consumption. So pull from Solar primarily and Supplement with Grid for the excess. And battery atm is for UPS mode.
 
Well, for now, I matched 4 panels according to the Elejoy. So I have 2 panels in parallel to bring the amps up to around 6A, and the other 2 panels are in series as they are already around 6A. So I have about 100V @ 5-6A available. Hopefully. We'll find out tomorrow (if it doesn't rain) what the output is.
 
could be the diodes / connections in the junction box - usually panels have 3 strings in series with blockingdiodes, you should be able to test each string inside the junction box.
Here is an interesting article about the topic: Bypass diodes
 
grundholm said:
could be the diodes / connections in the junction box - usually panels have 3 strings in series with blockingdiodes, you should be able to test each string inside the junction box.
Here is an interesting article about the topic: Bypass diodes
Click to expand...
I'll give this a test. I hadn't thought the diodes would cause the kind of issues I'm experiencing. That could explain why the jittery voltages. The MPPT starts to increase the voltage load and when I point is reached on the panel, the diodes break down dropping the flow drastically and the MPPT has to start over.

If I understand the combiner box on the back, the tabs are friction fit into the connections, so I could just disconnect the tabs and test the diodes directly without needing an external powersupply to backfeed the panels.
 
If the issue seems to be diode packs/wires, as apposed to the raw cells in the panels...

If you have removeable diode packs you might be able to find replacements - I was able to do this on some panels from Santan Solar. They were ~$3/pack, popped out old ones and pressed in new ones and and 'fixed' a couple of 300w panels this way.

In the non-removeable case, I was able to buy a 'generic' pack (with right number of diodes/leads) again for ~$3/pack and scraped off / de-soldered the old and soldered in a new pack and sealed with caulk - it seemed to work OK. It's only been a couple of years but outdoor caulk around the diode pack on the back side of a panel can hold up for a significant period of time.
 
Last edited:
Ok, so I found 2 more panels that were closely matched for voltage/current to parallel them to boost overall current output. So now I have 2P2P1P1P configuration. For the 4S the voltage is about 114V with zero sunlight. I got it wrapped up and everything back together after the sun went down and storm clouds started to roll in.
1725319378980.png

So here you can see todays "non" production. All it did was reach around 98-105V or so. The MPPT Charge Controller needs 120V minimum to trigger. So today was a zero production day.
Considering that zero direct sun voltage is higher than earlier direct sun voltage, I should be good for tomorrows test run.

If it can achieve about 125-130V, and actually get 5A from the string, then that's a decent >600Watt production. Which is double what I was getting with the 11S configuration anyways.

As far as the diodes go, of the panels I've looked at so far, they are fine. However, I pulled the tabs free from the diode housing and checked each string individually. Several panels have a single string dead. One of the tabs actually come off in my hand when I disconnected it from the junction box. Would explain the 0A on that one :p
There was a lot of oxidation on the aluminum tabbing, so I know that's not helping any. I'm going to need to pull the back off all the boxes and uses some sandpaper to clean them up so I can get a better reading. I'd like to be able to go in and cut some of the strings in the panel itself so that I can fully use them, but not sure I'll be able to do that without compromising the rest of the panel.
For instance, there are 5 tabs, which is 4 strings. Checking between T1/T2 I can get 11V @ 0.5A, test between T2/T3 is almost 0V. Between T3/T4 bounces back to 11V @ 0.5A. Problem is, I don't if I'd be able to parallel the output of T1/T2 with T3/T4 without string between T2/T3 interfering, because they are connected at the bottom of the panel.
If I could do that and get some functional panels, I could use them in places where I just need to trickle charge a battery to power lights or a small motor or such further back on the property where there's no power supply.. I'd hate to just toss them if they can still be somewhat used, ya know?
If I can't do anything, at least we have scrap aluminum to recycle.
 
1725400673310.png

Definitely got a lot better performance. Almost hit 640W (or just barely hit it) with half as many panels as before.
Today we had quite a bit of cloud cover with some rains. But it's nice to see that I can actually generate quite a bit more power than what I was originally. Just gotta fine tune with the panels that I have.
Looks like paralleling the lower current panels is a big benefit.
 
UPDATE!!!! Boy howdy!!! I got a heck of a deal today. $15 per panel, <5yrs old, zero blemishes on the panels. 250W!!!! I got 40 of them!! I told the kid (literally, he just turned 18 last week I think he said) if he has anymore left over after the next few ppl come by and get their orders I'll most likely be interested.

So now I'm in the process of replacing the roof mounted old panels with these new ones. I'm gonna practically triple or quadruple my capacity!! :ROFLMAO:

Figured I'd do 4 strings of 10s and then parallel those outputs. My controller is only a single input. That would give me about max 370VOC with about 80A Isc. So really potentially a max of 350 * 7 = 2450W. Even if only 2kW that's more than what I use currently. Easily charge the batteries and use them overnight and only have washer/dryer/waterheater on the grid 😎


I also wonder if that will get rid of the weird jittery MPPT that the controller is doing as these panels are in far better condition than the other ones. We shall see tomorrow. I'm getting them replaced tonight asap!!
 
Didn't have enough time to get everything swapped over. Darned time change. So I currently have things in 14s config, which will give a max 420VOC. Max controller is 500V, so that's good in that spot.

1732835120152.png


So hopefully tomorrow I will see a really good output generation. Battery SoC right now is about 58%. So should have good recharging conditions tomorrow. No rain in the forecast and good temps overall.
I don't have the 2nd row of 7s in optimal tilt, but still will get plenty of light.
 
1732882219503.png

1732882236444.png


UGH!!! this stupid storm is heading almost due East
:mortyscream:

730am and barely light outside and the panels are sitting at about 120-130V right now. so maybe it'll still be enough to produce decent power
 
Well, battery was recharged by 10am and there was barely grid usage throughout the day to power the little bit of loads I had connected. This includes my living room lights, computer, 2 monitors, fridge and a fan. Total about 300W spiking to 500-ish watts when the fridge kicks on.

First thing in the morning I briefly saw the voltage at 462V. The charge controller is max at 500V. When I got home I pulled one of the panels off the string. So 13s it is for the moment. I might do 2p13s. Not sure yet how I want to arrange everything. I have quite a few shadow points I have to consider.

The other thing I noticed is that the MPPT charts were smoother than with the older panels. I'm guessing something was going wrong with one or more causing the MPPT to crash. Maybe it couldn't handle the amps load or something. Not sure.

For instance, here's Thur graph with the old panels:
1732926753643.png


And then there's today's:
1732926826464.png

Far less jitter. Only reason this one is so bad, I'm guessing, is because it was trying to keep the PV input power low to match my current load out.
Battery was fully charged around 10am, which you can see the Power production just dropped to about 300W.

I've added 400W to the load and we'll see what happens on Sat.


Another thing that's really weird, is that there were voltage spikes throughout the night. Looks to be about 60-70V or abouts. We have a New Moon phase, so definitely not reflections from the moon. Anyone have ideas??
 
You must log in or register to reply here.
Back
Top