strikehammer
New Member
I have some 13 year old panels that have been exposed to the sun but not connected for several years. Would they be the same as those in constant use? How about if they were stored out of the sun but still the same age?
Do solar panels age the same if they are producing as they do when disconnected?
- Thread starter strikehammer
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hwy17
Anti-Solar Enthusiast
Better to worse:
Stored in dark > producing in sunlight > disconnected in sunlight
The difference between the latter 2 is real but not big enough to waste any time worrying about.
Stored in dark > producing in sunlight > disconnected in sunlight
The difference between the latter 2 is real but not big enough to waste any time worrying about.
Drunkin Solar
New Member
I have wondered this same question and look forward to the replies for it.
PotusGobbleBottom
Corn Pop was a bad dude.
So disconnecting in sunlight is terrible? Or is it just frowned upon? How many disconnects matter? Cumulative of course. But is it .0015% per disconnect or .1%?
Any chance you know the reason?
I both find this odd and not surprising at the same time. Weird feeling. lol
Hedges
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Sunlight would cause some degradation.
If connected in series, they would have different voltages relative to ground, which may cause varied amounts of degradation.
Not clear than degradation would be any faster if in use to produce power.
Out of the sun could be less.
Go ahead and use them. Test, if you like, but easiest to see how they perform on MPPT.
Possible reason for greater degradation in sun without load is that 100% of photoelectrons flow back through PV diode junction. If nothing else, makes diode hotter than if same energy dissipated somewhere else. Maybe air circulation is more important than sun exposure; I've ready rooftop mount degrades faster (or is predicted to.)
If connected in series, they would have different voltages relative to ground, which may cause varied amounts of degradation.
Not clear than degradation would be any faster if in use to produce power.
Out of the sun could be less.
Go ahead and use them. Test, if you like, but easiest to see how they perform on MPPT.
Possible reason for greater degradation in sun without load is that 100% of photoelectrons flow back through PV diode junction. If nothing else, makes diode hotter than if same energy dissipated somewhere else. Maybe air circulation is more important than sun exposure; I've ready rooftop mount degrades faster (or is predicted to.)
hwy17
Anti-Solar Enthusiast
I mean remaining disconnected in sunlight, or not operating in sunlight.
Actively disconnecting under load in sunlight is bad for a different reason, arcing on the connector.
Panels open circuit in sunlight degrade faster than when operating for academic reasons beyond me. Probably the higher voltage. The electrons get nervous and fighty.
PotusGobbleBottom
Corn Pop was a bad dude.
Ok, good to know. sorry for reading that wrong.
strikehammer
New Member
I ordered a Renogy 48v charger/inverter & will check the output when installed to see what the current is & report back. I expect about 85% of the 245w rating due to the age.
One other question, these have 24vdc output so I connected 8 of them in pairs to get 4 ea. 48v outputs in series to the charge controller. I believe the Renogy will take up to 145vdc, so should I configure them with 2 ea. 96vdc in series for better efficiency?
One other question, these have 24vdc output so I connected 8 of them in pairs to get 4 ea. 48v outputs in series to the charge controller. I believe the Renogy will take up to 145vdc, so should I configure them with 2 ea. 96vdc in series for better efficiency?
strikehammer
New Member
So if not in use, it would be better to short them out than leave the connectors hanging?
Hedges
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Expect 85% of 245W rating for brand new panels. Except under most ideal cool bright conditions.
Need label specs, not just "24V" to design array.
Higher input voltage not necessarily highest efficiency. Closer to battery voltage likely makes MPPT SCC more efficient and cooler running. But wiring could cost more, and/or have more loss. Voltage needs to be high enough even on hot days. Design is a tradeoff.
Need label specs, not just "24V" to design array.
Higher input voltage not necessarily highest efficiency. Closer to battery voltage likely makes MPPT SCC more efficient and cooler running. But wiring could cost more, and/or have more loss. Voltage needs to be high enough even on hot days. Design is a tradeoff.
strikehammer
New Member
This is ground mounted 6' up so charger is under array with only 4' of 6 ga stranded copper. Sounds like 48v is best for 48v battery config.
Hedges
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"48V" isn't a thing for PV panels. What does the label on the PV panels actually say?
Link to data sheet and manual for inverter?
Does it say what input voltage is required to charge 48V battery? Typically some amount of voltage headroom is required.
Link to data sheet and manual for inverter?
Does it say what input voltage is required to charge 48V battery? Typically some amount of voltage headroom is required.
I have had panels in Arizona, Southern Mexico, Honduras, Washington State and Idaho.
The panels in the hotter climates degraded faster than the panels in colder climates.
As I recall, the degradation rate on the panels was the same in use or disconnected over a 29 year period from 1983 through 2012. These were all 12 volt 32 watt ARCO panels , they may have been 33 watt, I just don't remember. Had an approx. 2 amp output.
The panels in the hotter climates degraded faster than the panels in colder climates.
As I recall, the degradation rate on the panels was the same in use or disconnected over a 29 year period from 1983 through 2012. These were all 12 volt 32 watt ARCO panels , they may have been 33 watt, I just don't remember. Had an approx. 2 amp output.
hwy17
Anti-Solar Enthusiast
This is exactly what I've seen debates about. My conclusion is that the difference is too small and the ramifications of shorting are too poorly understood. So I don't do it. But it has been proposed.
Hedges
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I've loosely plugged MC4 connectors together (to keep the weather out, but get them apart easily.)
The current flow through poor contact heated and warped the plastic. Going to have to replace the connectors.
You can buy weather caps.
Or I think fully mated in a short is fine.
Shading to keep sun off should reduce degradation.
The current flow through poor contact heated and warped the plastic. Going to have to replace the connectors.
You can buy weather caps.
Or I think fully mated in a short is fine.
Shading to keep sun off should reduce degradation.
strikehammer
New Member
I believe it requires 60a.
Kuma
New Member
For panels stored covered and protected from sun and elements, can they be used to replace the same panels that have been in use for 5 years, 10, 15 years... I have 455w Solarever panels with a spec'd degradation rate/power performance warranty of 15% over 25 years. I have one extra panel and am curious if the difference in performance would be enough to cause some issues if its producing more then the panels in use. This is for series strings with an SMA string inverter.
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