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Old 01-16-18, 05:45 AM   #1
davidmiller
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Default Second hand panels vs new panels - which to choose?

Hi ecorenovators!

I am facing a tough challenge. I need to choose between brand new and used solar panels for my 7kW PV system. I'm more inclined toward brand new panels simply because of higher efficiency and warranty. But on the other hand the second hand panels are so much cheaper...I would save few thousands with used panels. I did some research on efficiency and I'm sort of convinced that new panels are a better option...but a good friend of mine told me that panel efficiency is not important when it comes to ROI.

I kindly ask anyone here to write their opinion on this, maybe someone that bought used panels. I wonder that's the conversion ratio from sunlight to electricity on used panels...theoretically should be much lower right? but how much?

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Old 01-16-18, 10:19 AM   #2
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Can you inspect/test the used panels before buying them?
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Old 01-17-18, 08:58 AM   #3
Zwerius
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Quote:
Originally Posted by davidmiller View Post
Hi ecorenovators!

I am facing a tough challenge. I need to choose between brand new and used solar panels for my 7kW PV system. I'm more inclined toward brand new panels simply because of higher efficiency and warranty. But on the other hand the second hand panels are so much cheaper...I would save few thousands with used panels. I did some research on efficiency and I'm sort of convinced that new panels are a better option...but a good friend of mine told me that panel efficiency is not important when it comes to ROI.

I kindly ask anyone here to write their opinion on this, maybe someone that bought used panels. I wonder that's the conversion ratio from sunlight to electricity on used panels...theoretically should be much lower right? but how much?
I can only show you the efficiency of my panels over 14 years of use.
My website is in Dutch, but the graph speaks for itself: vertical=efficiency (based on panel area, not cell area) and horizontal=years
Degradatie en vervuiling van de panelen - geen energierekening meer:energie+ woonhuis van de fam. Kriegsman in Ootmarsum
The increase in 2011 was because a small ventilation pipe was removed from the roof. So a little shading of one of the six rows of panels had a significant effect.
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Old 01-17-18, 09:27 AM   #4
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David,

How room is there on your roof? In my perspective, this determines what you choose.

For example, if you have lots of roof space, then go with older panels. If you have only space for say 20 panels, then go with the new higher efficiency.

More panels, means more microinverters and racking. So set up a spreadsheet that compares and contrasts the two situations.

Does this help?

Steve
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Old 03-01-18, 03:28 AM   #5
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If they were cheap enough I would buy used.
In the past I have seen used panels going for half the price of new.
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Old 03-01-18, 09:32 AM   #6
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I agree with how much the used panels cost depending on the manufacturer. In my area new panels can be purchased regularly for 60 to 80 cents per watt. I have seen used 7 to 10 year old panels selling for as little as 30 cents per watt obo although a lot of those have been snapped up since the tariffs have began. The main thing with used is to be able to check each panel at full load to determine what their output is. Otherwise negotiate a lower price.
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Old 03-18-18, 07:38 PM   #7
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I would opt for one which can bring break-even faster. As i could see, used panel comes at a great price, you can go for it if you get a chance to inspect it before buying. buying it from places like ebay might not be a good idea though. You should also check out amazon, i found their pricing great recently.

Also used panel should be used only if it is grid tied; if its standalone (off grid), you should be able to get enough power from panel and new one will surely do better
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Old 03-20-18, 04:29 AM   #8
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The federal tax incentives as well as my local utility production based incentives(an additional 8 cents per kwh for 10 years) required that I installed new panels.

How much cheaper would you expect used panels to be? I've never come across standard 60 cell panels at a price on craigslist or ebay that I thought was a decent price compared to buying new when the additional shipping costs of ebay were involved and the loss of the incentives were gone and craigslist always had old lower efficiency panels, damaged panels, or a quantity that was either way too many or not enough.

If I was off-grid or incentives were not a factor, I'd likely go used if the price were dirt cheap, the panels were in decent shape, and the quantity was right for the application.

..but even then I've liked the idea of taking some of the 90ish cell panels and connecting them directly to used LiFePO4 cells with enough to suit standard 48v inverters and build in a simple system that cuts charging at max cell voltage and skip the BMS and MPPT(have the panels and number of cells configured for an panel MPPT match at 3.4v per cell which is pretty much where the charging voltage sits from like 50%-90% SOC. It would be dirt cheap off-grid without the short life of lead-acid..
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Old 03-20-18, 10:50 AM   #9
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I'm fortunate to be in an area with a lot of solar choices. There is even a liquidator in town. Renvu is only a couple hours away from me. A lot of the used panels I see appear to come from farms that are either upgrading and in some cases downgrading.
Here is a sample of what I consider a reasonable price for used panels.

https://sfbay.craigslist.org/eby/for...527235199.html

Living nearby minimizes delivery charges. If needed, a truck could be rented for fifty bucks or so and then of course gas but not too bad overall. It's true that the tax credit likely wouldn't apply. But at these prices who needs it? Unless the state was also kicking in a pretty good credit too.
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