NEW vs USED Solar panels - Side by side - Worth it?
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- เผยแพร่เมื่อ 29 ก.ย. 2024
- Used Solar Panels - www.santansola... (%5 Discount Code: RAY)
Are buying used solar panels worth it? when should I buy used vs. new solar panels? I'll try and answer these questions in this video. thanks for watching.
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If you want to get a hold you me you can email me at: diysolarpowerfunRay@gmail.com
I am not available for personal consulting. Please reach out to me in the video comments where I and others can provide feedback to you
Disclaimer
I am not a licensed electrician. Working with electricity is dangerous and can lead to injury or death, even when following documentation and instructions. I can not be held liable for such damage or injury. I am not giving or seeking to give advice on how to work with electricity. You should consult with a licensed professional whenever possible and get all work reviewed by an inspector and follow any local regulations in your area. I'm documenting my projects for informational purposes only. Electricity can kill you! BE CAREFUL!
The small advantage you get from higher voltage is more than negated by the loss even when partial shading happens.
Yeah. Unfortunately right now I can only have 5 panels. The odd number of panels doesn't work great for a series configuration unless I put each panel in parallel with each other... but that wouldn't work with my inverter.
@@diySolarPowerFunWithRayuse more than one charge controller
I think you lose less when in parallel than in series (but it depends on the bypass diodes) when shadows are on your panels. I think that is why boaters run theirs in parallel.
Generally speaking, at the panel level parallel is slightly better than series in terms of being able to contribute varying amounts of current in partially shaded conditions. This is because the voltage varies only a little over a fairly wide range of currents during power production. But, there are two problems that make it NOT a slam dunk choice:
* First, unfortunately, these gains tend to cancel out by wiring losses due to the far higher amps being transmitted on the wiring. Cable losses are a function of the square of the current, so it is completely non-linear. Too few volts and too many amps can seriously mess up the system's efficiency. If you double the voltage and halve the amps for the same power, the losses are cut by 75%, not 50%.
* Second, higher volts results in far higher charge controller efficiencies. And in addition, all MPPT charge controllers have a minimum "start" voltage and an optimal MPPT voltage range. You want the operating voltage going into the charge controller to be optimal even in shading conditions so you don't want too low a voltage that would otherwise cause the MPPT controller to drop-out. This argues for a minimum of two panels in series regardless of the conditions or configuration.
On a boat, the cables tend to be relatively short, so parallel is somewhat more preferable. At least as long as the boater doesn't go overboard. If the boater only has two panels, a series configuration is usually preferable. If a boater has four panels, a 2-series/2-parallel configuration is usually preferable. If there are six panels, either a 3s2p, or a 2s3p configuration is preferable. And so forth.
On a house, the cables are much longer and losses from high currents can be quite serious. Plus you generally have a lot more panels. Under these conditions, series is typically better. So with 18 panels you would commonly see 9s2p, and with 27 panels you would likely see 9s3p. And so forth.
Finally, more volts and less amps == less stress on the equipment, and discrete pieces of equipment required. Which again argues for at least some panels in series in any configuration.
@@junkerzn7312 I see. I think Sailboats have lots of shadows and maybe, just maybe they could be better in parallel
Boats likely have a shorter run as well ...so 36v or 70v would not have too bad a loss in like 30-40 feet run in a boat with 10 or 12ga wire
I'm using the used SanTan panels. Honestly, I love them.
Yeah, They're awesome! I've had them at 100% efficiency on some days.
I have 46 used panels from santan solar. Ill be buying 34 more. Ill never buy new panels
@@SergeantSOLAR cool. Use my discount code. I plan on buying 25.
We are so happy to hear that! ☀🙌🏼
@@SanTanSolar yep I have 75 of them in a field though I did get a squirrely one in the last batch I bought at the beginning of the year. Don’t think it was intentional. Love the other 74.
Used panels are making 3x real watts per $. Just don't pay more than $50 for them. Santan is probably getting them for $5 scrap value.
3 times the cost for 4% increase in efficiency? Does not seem worth it to me.
I have 2 5000 watt Growatt all n one inverters. My voltage at peak is around 385 volts when dark clouds it drops to 195-230 volts. so it stays in my range of 150-450 volts. But still on a dark day do not expect much from solar panels since the sun does not penetrate the clouds. I tell everyone buy as much solar as possible and max your inverter out which still isn't max with the 33% rule to meet code. 9400 possible watts I have seen 9800 watts peak. on the low side I have seen 40-60 watts during a storm with super dark clouds. More batteries to make it past those days are needed.
Cool. With my combiner box, I am able to add three more strings of six used panels from a make shift ground array. . So that would be 18 use panels total... 5 new higher voltage panels on the roof. I am planning on using this setup to power my critical appliances in case the power goes out. I'm hoping with the extra panels I can still power the critical appliances during cloudy stormy days.
Speaking of less power loss with series.. you can try and eliminate the return run of wire by connecting to every other panel..thus cutting out some wire.. but it does make it more confusing arrangement.
You're probably better off with a lower voltage controller.
The bypass diode bypass the panel, so with 60v minimum voltage controller if you have two panels in the sun you get the power of two panels, if you have the 120v minimum voltage controller, you need yo have 4 panels in the sun for it yo work.
The 20w you getting out is basically the current off a shaded panel in your test.
In rv you don't have long Cabela's that loses voltage, so I wouldn't worry about that too much compared with what you loos in shading. In a residential setup with no shading problem, yeah run as high voltage as possible
Go with lo voltage controller and put the panels in parallel, 2x2 or 2x3 or get a controller with bigger voltage spread between minimum and maximum voltage and you will have much better results
Thanks, yeah. I think that's best for most people. I'll try this one out on my RV for a while and see if u regret it.
Looks like when space is limited, then new panels is the way to go. But if you can build as big as you want, then used panels is the way to go.
Oh, one other thing to note with used panels... and in this case I mean old panels. The oldest of panels might not have bypass diodes at all. Most older (15 years) residential panels do, but often they only have ONE bypass diode. Literally, no sub-strings in the panel so any shading anywhere on the panel takes out the entire panel.
Modern panels have three bypass diodes, breaking the panel up into three sub-strings. And half-cell solar panels go a step further, split the cells, and you get six zones on the panel instead of three zones. Still usually with three bypass diodes. But effectively six zones.
So if shading is an issue, particularly on a boat for example, half-cell panels will have much better yields than normal panels. You pay for it, though. If shading is not an issue, half-cell panels don't help and the only negative issue for older panels (that have been vetted for damage) is the lower efficiency.
Thanks, that's good to know. 👍 I'll open the back of these and check how many bypass-diodes they have.
You know used isn’t bad. Most depends on quality and how used they are. Sometimes you can win big if you know what you’re looking for in solar panels and chose the right ones. Sometimes you get refurbished where the customer before just changed their mind or who knows what and you can score big that way too.
Good video. What a monster jump with those new panels.
Better with a 3S2P array I would of thought. Parallel holds better in shade than series.
I'll have to see how this setup works.. I may not be able to fit that sixth panel up there so 5 in series might be my only option for now with this inverter.
Your wires are gonna be so short I'd put everything in parallel and find a controller to work with that or you could even use a contactor in a voltage meter switch.
Thanks. I'm not sure I'm following. What's a contractor in a voltage meter switch?
@@diySolarPowerFunWithRay A contactor And a voltage switch
If space is a premium go new. If it is not go used. I feel like I’m starting to decorate in silicon and glass for the property. Free energy though so it works for me.
Solar panels will lose about 15% efficiency in the first 10 years, then they level off. For home and project use this isnt a big deal, but for large solar arrays its significant enough to matter. Its better to have several parallel strings of smaller cells if shading is an issue as the shaded cell is a reverse biased diode. Really bad things can happen if it is a high voltage string and a cell gets blocked.
Used panels are a bit of pot-luck. I have found that the normal percentage degradation of the solar cells themselves is not ever an issue. Where the issues come up is with (A) Actual damage to the cells, and (B) Damage, cracking, and general wear to the seals around the edges of the panels. This is what causes panel failures on used panels.
So check these carefully. If you see water damage anywhere under the glass, or any clear shorting (black marks, heat damage), or any obvious cracks, don't use the panel. If you see obviously cracked seals around the edges, try to re-seal those. Finally, used panels should always be mounted at a significant angle to reduce stress on the already old seals. If the panels are too flat and water is able to collect on top of the panel, it really doesn't take much for that water to be able to penetrate under the glass and damage the cells.
It looks like the charge controller isn´t good at handling shade management... If it would, it should pull the voltage down a lot more in your simulated shading conditions, depending on how many bypass diodes the Panels have. For the used panels the voltage may be too low then, but for the new panels at least for the partly shaded case it would be possible to get some more power. If you want to get the maximum shading performance out of this setup without changing the inverter maybe it´s worth to take a look on some optimizers for each module, but this is something for experimentation, because nobody can forecast how well optimizers and charge controller from different manufacturers will work together - but if it works I think you could get much more power in shading and keep the existing hardware
thanks do more of videos like these
Thanks for the feedback. I'm open to any recommendations..
@@diySolarPowerFunWithRay then kindly discuss about the PID effect. because from what I've read sofar. it's caused by grounding the panels to ground... literally no one is talking about PID effect on solar panel man.
Good test - very informative, thanks.
Can you ship in india only 2 pieces with low price
Which specific panels are the ones you purchased from Signature?
I think they are running low on stock and aren't listed on their site all the time. They are the 315 watt Canadian Solar mono panels.
@@diySolarPowerFunWithRay Thanks again.
why not go for 430+ watt panels or even some of the new 500+ watt one's 315watts seems on the low side for what is out there now
Thanks. After a ton of measuring I found that the 39"x65 315w ones fit my rv best.
would have liked to see the cables connected to the other panels as soon as first results written down. one hour movement in sun and conditions makes a big difference.
also the blue panels had the same issue with your charge controller, you needed one more pannel.
the other variable is the black panels get hotter than the blue and will put out less as they get hotter.
but if i was rich i would buy new. till then its secondhand cheap panels.
Yeah. The cables were swapped right away. Maybe 5 or 10 min difference. I tried to do it fast because of this.
I also usually like the used solar panels. I plan on using used panels for my other projects. One other benefit of buying used solar panels is that you can order a few extras and sell them on locally(facebook marketplace, etc) in order to pay for shipping costs. I'm not sure I can do the same thing with buying new solar panels.
@@diySolarPowerFunWithRay never buy from those bulk secondhand panel guys, they double the price .just beat them to the guy who just realised he was tricked into buying a system too small and wanted to make money from the power company hahaha lol. you can get his panels for $10-20 each as he will try sell you the useless grid tie inverter , just let him think its worth more than the panels.and he can sell it separate. he may even throw in the mounting rails.
@@RomansSeven7 who do you get your used panels from?
Why Do You ... Fractionalize Whole Numbers ?
I probably messed my math up. Not sure. It's been a while sense I made this video.
I think the Charge controller cuts off at that lower voltage input. As the amps would be too high for it to handle. Not sure about how that charge controller works either.. As the lower the voltage. The higher the amps..And charge controllers are designed to protect against this...
I would add. This is what makes Micro Inverters king of the block on bigger arrays..
Not clouds its chemtrails spreading out .
hmm. not sure what that means.
When you do a test of this type you should also account for the gage of wire and the length of cable from the panels to the solar controller. There are losses in the wire also and if you gage is to small, then ability to transport your power is reduced.
I bought several used 300-watt panels for a home project and had wonderful success so far. Of course, I ask for age and some history of the panel. Many of these come from failed businesses for whatever reason. Found a guy selling these for $50 and were only 3 years old. Many folks argue for and against the theory that solar panels degradate over time. Heard all the arguments from both sides and still not sure who to believe. Any it was well worth it for me.
Good point. I'll ask that next time I buy. I'm gonna get a pallet next.
If one panel is shaded over the 5 it will lose 50% power using series. Putting them in parallel you still have 80%
Yeah, I'm not liking the solar change controller I was using for this test. Maybe I'll try it again with a different one.
@@diySolarPowerFunWithRay consider 2 or 3 charge controllers. What's the panel and battery voltage. I have taken my 235w 30v solar panels to pwm controller for each panel. Works a treat at 24v
@@johnswift1736 Now that would be an interesting test: 3 cheap pwm's on each panel vs 3 panels in parallel connected to one expensive mppt.
@@diySolarPowerFunWithRay also having a charge controllers on each panel stop decreases in power if one panel degrades. You will only get the level of the worse solar panel in series.
considering any state I have ever seen requires using a licensed approved contractor or company it makes using used solar panels worthless unless you are off gird.
Yes it is a little more difficult. There is another TH-cam channel called projects with everyday dave. He has a pretty good tutorial doing it yourself and getting permits. New panels are a good option though as well
thoght this was going to be interesting but totaly rubbish comparison due to mono vs poly and wattage difference this is not old vs new
Used panels are pretty much all poly... and to me, it seems that new panels nowadays are going to mono. So this is mostly a real-world comparison of what type of panel you would get if you buy used and what you would mostly likely get if you buy New. I like used panels. But if I was going to spend the extry $ to buy new I definitely would buy mono. Thanks for the comment.
For shading or partial shading of a panel think Tigo dc optimizer on the affected panel.
Thank, I've messaged them. I'd love to give it a try. Hopefully they'll get back to me.
The prices of solar panels in Iraq are very expensive, the price of one watt is at the price of one dollar
You know what the price of freight forwarding would be to ship to Iraq? I know some people ship these used solar panels to different parts of the world. Including Africa
I have the same growatt inverter. I did not know you can use Canadian Solar Panels. I take it they are no different.
Yup, they work great
Good testing, when using panels in series you have to learn what limitations might happen.
I wonder what a Victron charge controller would do in that same setup. I have an MPPT 100 30 Smartsolar and it can run full wattage from 18v to 100v.
The diode in a solar panel is to stop any reverse current that may be present if you connect a panel incorrectly or if there is a fault with your controller. It cannot prevent a shaded panel blocking the whole line of serial panels. Your best bet is to have a parallel/series configuration to keep your voltage as high a possible but keeping the shade protection to prevent the whole output being blocked by totally shaded panel
This is a common misconception. If you look up bypass diodes this is why they put them in solar panels. Solar panels 20 years ago or 25 years ago may have been missing the bypass diodes but nowadays they all have them
Yeah that's not true you can throw a blanket over a whole panel wired in series and only loose the output of that panel.
But some patterns of shade can drastically effect the output of the whole string.
The diodes do both jobs prevent hotspots from reverse current and help alleviate some adverse effects of shading.
I so appreciate your videos, was gonna give up on solar concept till I watched your videos, Now I will give it a go....appreciate it.
Nice, Thanks.
@@diySolarPowerFunWithRay Used your link to order so I hope you get some kind of kickback
@@SarahStuff-p5u nice, Let me know if you have any questions. You'll love them
@@diySolarPowerFunWithRay Just ordered everything except the wood, wish me luck hehe
Higher voltage does mean less loss over a given length of cable, from your panels to the SCC, but you're mounting them on your RV and only running them a few feet, so that's basically a non-issue. This is especially true if you use a 10AWG cable. The problem is you chose an inverter/charger with a very high input range; I think you're going to regret that. As you saw when testing the newer panels, with multiple bypass diodes, when the voltage drops too low you basically get nothing from those panels. Normally you would address this by wiring the panels in parallel, or a 2P-2S arrangement. You cannot do that because your SCC doesn't even start working until the voltage is quite high from the panels. When you added the 5th new panel, you had enough voltage coming in for the controller to work, but what happens when 3 of your 5 panels are shaded? You'll get basically no power. In contrast, you could have a 2P-2S array, with a SCC that accepts lower voltage, and if one pair of your panels was shaded, with the other two in full sun, you'd get 50% of expected input. You're going to hate that charge controller.
I may regret it.
I mainly plan on parking in the sun. Especially if I will be in an area where I will need the air conditioner. The reason I got this charge controller is because of the accepted larger voltage range. On cloudy conditions I would like to have the ability to add large strings of additional panels. However I still need to test that this charge controller can I accept power in real world Cloudy conditions. According to the specs and in theory it can but I still need to put it to the test. I hope I don't regret it
The problem is having a 48V system (nearly 60V full battery). So it needs that 60V+ to ensure the battery can charge. Some like the Victron SCCs are able to use Vbatt +1 potentially lowering your needed voltage.
24V systems are the way to go for ~1000W arrays or less. Especially mobile applications. The problem is lack of 24V inverter choices.
@@andrewt9204 Do you have a link to the Victron SCC you speak of? I don't think that's corrects. I couldn't find it anywhere. The lower voltage charging would be awesome though.
You're right with the 48v systems functioning on smaller solar arrays though. You'll want the space to fit at least 3 of these sized panels(wired in series) to confortably get the required 60 volts to charge the 48v battery. If you have the space I'd definitely go 48v.
@@andrewt9204 - Very good point! My home office system is built for 24v, using an MPP 2024 inverter, since my peak draw is barely over 1,000 watts and my solar array (for this system) is only going to be around 1,200 watts.
Help me out here. Everyone talks watts. Why? Amps are what you need to charge a battery quickly. No matter what the watts are, you will only charge as fast as the solar panels are rated at... i.e... 8 to 11 amps. Try charging three 24v 300ah LiFePo batteries discharged to 20% using 8 amps. It will take at least a week or more. Buy a controller that will start charging at a lower voltage and then parallel the panels for more amps. What am I missing?
In my example the amps are increased with my charge controller. You can arrange your solar panels however you would like. Just make sure that it is within the specifications of your charge controller. For example if I run all of my solar panels in series my volts go really high but my amps stay the same. Where the magic happens is within the solar charge controller. In the example I mentioned the mppt solar charge controller will take the volts and amps and convert them to what the battery prefers. In the example I mentioned it will decrease the voltage and increase the amps. It does all this while being very efficient and preserving total power(watts) coming from the solar panel. Hope that makes sense. Sometimes I am bad at explaining things.
@@diySolarPowerFunWithRay 1200w =120v x 10a same as 12v x 100a inverse proportion .
Oh you got to edit your videos this is horrible
I try to, what specifically bothered you.
@@diySolarPowerFunWithRay the cutting mostly it doesn't transition smoothly from part to part
You can put slide out panels underneath your main panels problem solved 👍
To be honest I haven't looked at slide out panels but that seems a little too complex for my needs. I am also not sure how slide out panels would do in the wind. I want my solar panels to Give Me Freedom. I don't want my solar panels to restrict where I travel. It always seems like I am driving in a strong headwind. These panels should give me plenty of power. I could whoever see advantage of slide out panels if I was living in my RV full time or for half the year and not traveling a bunch.