Nah I'm jokingly reacting to @jwelter99 's comment that it isn't pretty lol. Agreed, it's very functional but not (yet) pretty. I didn't have time to neatly integrate it during the time I was picking up the new RV.
The "Meg" Build
- Thread starter Lt.Dan
- Start date
Nah I'm jokingly reacting to @jwelter99 's comment that it isn't pretty lol. Agreed, it's very functional but not (yet) pretty. I didn't have time to neatly integrate it during the time I was picking up the new RV.
Lt.Dan
Solar Wizard
First full irradiance day for me, and I think my 2880 watt PV Array peaked at 2071 watts so far. Which is really close to the 75% i'm reading most people say to expect. Especially since all the panels are flat on my RV roof.
Lt.Dan
Solar Wizard
I got 12 of the SanTan Snail trail panels hooked up, just laying on the ground, wired in a 6s2p fashion. But the most I saw all day yesterday was 1800watts out of 3000 watts worth of panels. I checked amperage from each series string, which 1 was making 6.02 amps and 2 was making 5.87amps at ~150V. Something that also concerned me, is the panels are 30.3VMP, so 6 in series should be ~181v. Is it coincidence that it is low almost exactly 1 panels worth? Or is this normal?
Did you check each panel separately with just a meter to see if it was putting out full voltage (~37.6V for those panels) with no load? I always do this to make sure panels are ok before connecting them up.
I then hook them up and carefully test the full string voltage that it is expected also under no load. So in your case the ~230V (6*37.6) or so.
Last edited:
Lt.Dan
Solar Wizard
Thats what I figured. Voltage tests next, yay! Its only 97* today...
You can take it easy and just disconnect the string and measure that first. If not close to ~225V then split the string and test, and then keep on going in the direction of the lower than anticipated voltage.
You can also teach kids or wife to use the volt-meter
Lt.Dan
Solar Wizard
Lmao my oldest is only 3, so probably best I ask the wife to do it ?
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 21,900
225VDC. Test leads on DMM are not touch-safe.
Better do this one yourself (confirm life insurance is paid up first), start your wife's EE education with 9V battery on the tongue.
I had a spare DC rated switch and MC cables, so I connected DMM and made a PV panel tester. The panels are connected with switch open to read Voc, then switch is closed to read Isc. Without a switch, rotate panel edgewise to sun so current is near zero before touching probes for current measurement.
For reference my son was around 13 when he was not a safety risk with basic hand tools that did not take more supervision time then he contributed to whatever project.
Lt.Dan
Solar Wizard
So I am going to mess with it a little more tomorrow. But right now its 5:45PM and the panels are starting to taper off pretty fast, but weirdly the Voltage is going up? Its currently at 178V, which its supposed to be 181VMP all together. I dont understand how less light leads to higher voltage?
Voltage output will go up when panels are cooler. During your earlier voltage reading was the temps a lot higher?
Lt.Dan
Solar Wizard
Eh a little bit. It was 93* today, and its 87* now, but they were in the sun during the day. Im just surprised it would drop that much??
Not enough, I was thinking if it was high 90's during day and down to 70's or so you might pickup quite some voltage.
You really need to get the raw panel voltages to make sure not MPPT playing Jedi mind tricks.
Lt.Dan
Solar Wizard
I'll check it tomorrow. Thanks guys
Lt.Dan
Solar Wizard
Well the battery is dead, and the charger is set to charge at 100 amps, so the charger should be taking everything it can take.
I also was just out there moving some panels and I think I found my culprit.
Looks like a burnt bar that attaches the individual cells
I also was just out there moving some panels and I think I found my culprit.
Looks like a burnt bar that attaches the individual cells
That certain could explain it!
Lt.Dan
Solar Wizard
Seems all of them have some form of burn/corrosion. I did connect the 12 worst looking panels that San Tan sent me, but None of them were burnt when I plugged them in, so this happened in the last 3 days. I wonder if I test them and prove them damaged, if they will replace them?
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 21,900
Crackle patterns under the glass seem to be long term effects, maybe moisture, delamination and the like.
If conductive material had settled inside the lamination (ion/water intrusion?) then while potential is applied that might etch conductors away.
Or if the conductors were thinned by corrosion, carrying current could cause the to fail.
There is nothing you can do to over-current anything inside a PV panel except connect it to sources able to supply current in excess of its rating.
A short string (1 panel) connected in parallel to multiple longer strings of panels (2s3p) would backfeed excessive current.
Connected in series, would put too much current through the bypass diode causing it to overheat and probably melt something. If it went open, would apply excessive reverse-bias to the cells.
There are various modes of cell degradation. I've been reading of "potential induced degradation" which apparently occurs if PV panel circuits are more negative than its frame. It was said that having negative wire from array prevents this, but some systems use un-grounded PV circuits.
Quality of lamination process?
https://greendealflow.com/the-five-most-common-problems-with-solar-panels
If the panels fail to perform and not due to abuse, I think SanTan would replace.
If conductive material had settled inside the lamination (ion/water intrusion?) then while potential is applied that might etch conductors away.
Or if the conductors were thinned by corrosion, carrying current could cause the to fail.
There is nothing you can do to over-current anything inside a PV panel except connect it to sources able to supply current in excess of its rating.
A short string (1 panel) connected in parallel to multiple longer strings of panels (2s3p) would backfeed excessive current.
Connected in series, would put too much current through the bypass diode causing it to overheat and probably melt something. If it went open, would apply excessive reverse-bias to the cells.
There are various modes of cell degradation. I've been reading of "potential induced degradation" which apparently occurs if PV panel circuits are more negative than its frame. It was said that having negative wire from array prevents this, but some systems use un-grounded PV circuits.
Quality of lamination process?
https://greendealflow.com/the-five-most-common-problems-with-solar-panels
If the panels fail to perform and not due to abuse, I think SanTan would replace.
Lt.Dan
Solar Wizard
It would make sense of water intrusion. On day 1 I had turned on the sprinklers to keep the dust down (these are placed in a large horse arena), and day 2 it rained a little. So water on the thin bus bars inside the panels + heat + electricity = toast.
I'm gonna test for VOC and short circuit current when the sun gets a little higher and see what I come up with
I'm gonna test for VOC and short circuit current when the sun gets a little higher and see what I come up with
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 21,900
If these are bargain panels from SanTan, are they originally Trina?
Apparently Trina had a quality issue a while back, leakage from PV circuit to frame. They replaced entire arrays of panels under warranty and presumably fixed the process issue.
That could explain how panels with labels stripped off reached the used market. Maybe they perform with varying degree of reliability depending on the environment they get deployed to, and what they had already absorbed.
SanTan has of course tested functionality/output, but may not have tests to show latent issues?
Panels are supposed to be reliable in almost any environment, but results have varied.
I would make sure the panels always have frames grounded for safety.
Hopefully SanTan replaces them, or maybe lets you apply purchase price to a different model.
Apparently Trina had a quality issue a while back, leakage from PV circuit to frame. They replaced entire arrays of panels under warranty and presumably fixed the process issue.
That could explain how panels with labels stripped off reached the used market. Maybe they perform with varying degree of reliability depending on the environment they get deployed to, and what they had already absorbed.
SanTan has of course tested functionality/output, but may not have tests to show latent issues?
Panels are supposed to be reliable in almost any environment, but results have varied.
I would make sure the panels always have frames grounded for safety.
Hopefully SanTan replaces them, or maybe lets you apply purchase price to a different model.
Lt.Dan
Solar Wizard
Well I just got out there and tested them all for VOC and short circuit current. All of them passed the voltage test between 34-36v. Current was low around 5.4a +/- .2a. But short circuit amperage should be around 8.27a. Im guessing this is just from inefficiencies with dirt on the panel, smog (which we hold i think in the top 10 in the country), etc.
I rearranged them to point more south as well, and while hooking them back up, an MC4 connector fell off. Looked like a bad crimp. So I crimped a new one on a well with oxguard inside of every connector, its showing 160v on the LV6548 and 11amps.
Should I still be worried?
I rearranged them to point more south as well, and while hooking them back up, an MC4 connector fell off. Looked like a bad crimp. So I crimped a new one on a well with oxguard inside of every connector, its showing 160v on the LV6548 and 11amps.
Should I still be worried?
Lt.Dan
Solar Wizard
Stats right now
PV1 is the panels on the ground
PV2 is the panels on the roof of the RV.
Both are different models too. Hence the different voltages etc
PV1 is the panels on the ground
PV2 is the panels on the roof of the RV.
Both are different models too. Hence the different voltages etc
Lt.Dan
Solar Wizard
Sorry, to answer your question yes, they are old Trina panels. Some of them are even from different batches/years because the boxes on the back are different on some.
Similar threads
