Author Topic: Quality of chinese Ebay solar panels vs reputable source?  (Read 1561 times)

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Offline Freesurfer

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Quality of chinese Ebay solar panels vs reputable source?
« on: February 19, 2019, 04:00:36 pm »
Hello, forum. This is my first post on here. I have been following Dave on youtube for quite some time and it is one of my favourite channels, and thought I'd make an account on here and say hello :-)

I have a project going on with renovating an old boat house and need some more permanent (not to mention silent!) solar powered off-grid solution for electricity. Today I have a petrol powered generator sitting there, but it is noisy and a bit overkill for just some light electricity usage.

I have been looking in local stores where a 30W panel costs about 100 euro, and a 80W one costs about 200 euro. However comparing these to ones sold by chinese Ebay sellers, I realise that I can get them much cheaper on ebay. For example here's a link to some panels that are like a third of the price from a local store:
https://www.ebay.com/itm/30W-12V-Semi-Flexible-Solar-Panel-Battery-Charger-Cable-For-RV-Boat-Motorhome/372493504585?hash=item56ba57d049:g:RJIAAOSw8LBaydBK:rk:11:pf:0
These particular ones don't have an aluminium frame, but there are aluminium ones with comparable prices.

However as with most things on ebay, I am sceptical about the claimed power and overall quality of the panels. Does anyone have any experience with chinese ebay solar panels and how they compare to similarly rated panels from more reputable local retailers? Do they usually perform up to their claimed performance? Perhaps someone can recommend some cheap panels?

My application will be for maintenance charging a 48V battery bank made up of a bunch of 12V/40Ah VRLA batteries (I will have 8 or 12 of them in an array, with groups of 2-3 paralleled, and 4 of these groups in series). I think the easiest option will be to get 4 solar panels as well as 4 cheap solar controllers to charge each individual group of paralleled batteries. To make sure they are properly balanced. They will be used in the boat house for powering a 48VDC - 230VAC inverter for lights, charging hand drill batteries and such. I think 120W should be plenty for maintaining the battery bank as we don't visit the place that often, and the panels will have plenty of time to recharge between each visit. Not sure if I can trust the 4x30 = 120Watts, but at least it should be better than Solar Freakin' Roadways, or what?
 

Offline coppice

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Re: Quality of chinese Ebay solar panels vs reputable source?
« Reply #1 on: February 19, 2019, 04:03:46 pm »
100 Euros should get you a good quality aluminium framed 300W panel, not a 30W one. Your local supplier sounds like a rip off.
 

Offline Freesurfer

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Re: Quality of chinese Ebay solar panels vs reputable source?
« Reply #2 on: February 19, 2019, 04:15:33 pm »
Rip-off indeed, as with most things in local shops here. That's why I am looking for alternatives and scouting ebay (but no use buying things there at a third the cost there, if they only perform a third of their claimed performance). I am not sure if I have seen panels as cheap as you suggest though. At least not unless ordered in larger quantities.
 

Offline OwO

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Re: Quality of chinese Ebay solar panels vs reputable source?
« Reply #3 on: February 19, 2019, 05:29:36 pm »
100 Euros should get you a good quality aluminium framed 300W panel, not a 30W one. Your local supplier sounds like a rip off.

Last time I checked $0.3/watt was the bulk pricing of the bare solar cells, and the finished product was more like $1/watt. Where can you get a 300W panel for $100?
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Offline fourtytwo42

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Re: Quality of chinese Ebay solar panels vs reputable source?
« Reply #4 on: February 19, 2019, 05:32:59 pm »
I don't buy anything electronic from China on EB as in mine and others experience they are frequently fakes or under-spec parts from the grey market, if something is ridiculously cheap there is a reason!

The other issue you need to take into account is return's not only are they nire impossible on EB but you get to pay the shipping so it's far better to look in your own country first :)

Personally I only buy panels made by manufacturers I have actually heard of and have a website where I can check the specifications.

Finally be very wary of "leisure panels" they tend to be very high cost per watt and of unknown parentage.

You might be better with some non-leisure high voltage panels and a reputable charge controller IMOP
 

Offline metrologist

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Re: Quality of chinese Ebay solar panels vs reputable source?
« Reply #5 on: February 19, 2019, 08:18:54 pm »
I bought a 100W Chinese panel for $96USD shipped. Something like NuPowa brand. It did everything advertised and I've had it on the roof for a couple years now. No problems.  I just use a cheap PWM controller and a SLA batteries typically and I also have an MPPT 42V Li-ion charger connected for the e-bike.

I wish I'd bought a setup for at least 4 of them, but would rather have 300W panels. These are poly-crystalline, mono-crystalline are more efficient.
 

Offline george80

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Re: Quality of chinese Ebay solar panels vs reputable source?
« Reply #6 on: February 19, 2019, 09:00:59 pm »

As said, fleabay panels are notoriously under spec. The 30W panels you are looking at are probably20's. At best.
For some reason, Chinese sellers on fleabay the wold over tend to be a bunch of lying, deciptful Ripoff merchants and outright Crooks.  They put Ficticious numbers on everything they sell then try and make BS excuses.

Before I woke up I bought some LED lights. Nothing like the rating advertised when Measured with a multi meter. When I Complained and send pics of them on the multi meter I was told they have an equivelent output to xxxW  Nah, not wearing that you crook.  Got my money back after a fight ( Wanted to know If I was an electrictian and qualified to take measurements, I said yes, are you?)  but learend my lesson. Measured some lights and things mates Bought with the same sub par results.

Given you are wanting to do a proper system, what are you even looking at tinly  little 30W Panels?
I have bought and set my house up with proper 185-265 Panels I have bought used  that have been taken off houses for upgrades.  Just bought 4kw worth of 260W panels and an inverter for $400.  Even the people charging way too much are only asking $50 for up to 250W panels.
Fleabay panels are not cheap from China, they are a rip off too.

I usualy buy from Gumtree or Craigslist as they tend to be offered there a lot cheaper than fleabay. There  are often odd 1-2 panels listed there as well as completer 2Kw+ sets.

I have bought over 120 used panels now and just discovered my first bad one last week. It's got a hot junction burn mark but when I tested it, the thing is still doing good output. I'll probably get up and change it today given it's nice and cool and overcast. I have a bunch of spares so I'll just replace it with a slightly bigger panel I have and all will be good and the array will be back up to full speed.  We did have some VERY hot ( 47oC) weather here a few weeks ago so the fact only one panel has shown a problem I think is great considering what I have paid for them all.

Domestic panels are all designed for 20+ year service lives and if you buy them 7-8 years old for $25 ea, you are getting a lot of years of power for very little money.  Everyone talks about the performance drop off with age but really like so many things in the solar game, I think it's well over blown.  I have got fractionaly HIGHER output than rated on occasions like the other day. My 4.8 KW array which usualy doesent do much more than about 4KW was pumping out 5.1 KW. I thought the inverter had gone on the fritz then I flicked on the other meter I have on that array and it said the same thing. Checking other arrays they were all doing screaming outputs as well.  In my repeated experience, the weather is a lot more significant than any panel degradation.  If it's overcast, new panels will be down and underperforming too.  I have in fact found that very light passing cloud gives the best ( short term) outputs due to something called  Cloud edge effect. In a nut shell it's basically the water droplets in the clouds acting like little magnifying glasses and concentrating the suns radiation.   You might think is a little overcast but then see your arrays are performing outstandingly.  Doesen't last long but gives a real boost when it does and even older panels can really crank out the watts.

Given yo are running 48V you may  need to run 2 panels in series to get the voltage up high enough for the controller. Either way, even if you get 250 Panels I'd get 2 anyway.  There is no such thing as too much solar especially in winter when the lower solar radiation would mean that 500W of panels is probably outputting 200W, IF they are in the right orientation and tilt to start with and a whole lot less if they are not. Throw in some overcast  weather.  You'd be lucky to be getting 5W per 30 W panel.

The other BIG benefit of having plenty of panels is you may not need to discharge the batteries at all when using the inverter. If the power coming from the panels equals or exceeds the draw, the batteries are never discharged and that's the best possible thing for battery life.

I have a play setup with panels, a Good PWM controller , Some batteries and a UPS as the inverter atm.  I hooked in 1 Kilo of panels with the 4 in 1  cable adapters I just bought and was running the UPS ( only 600W) flat out with dummy loads and was charging the batteries from where I discharged them while setting up and was still running the loads.  This is what you really want to aim for. The less you dig into the batteries reserve the happier they will be and the longer they will last.

Anyway, I'd be looking for used Household type panels of 185W and above. Don't waste your time with garbage fleabay and pissy little 30 and 80W panels. Get some used panels where people have upgraded to larger / newer systems. Much cheaper, infinately better and more practical.
And don't be afraid to buy a lot more than you think you need. allows you to expand the system if you want and takes all worry about power away.
Maybe you could even charge neighboring boat sheds for power and get a return?  :0)
 

Offline Red Squirrel

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Re: Quality of chinese Ebay solar panels vs reputable source?
« Reply #7 on: February 20, 2019, 05:23:32 am »
I find it's very hard to find solar panels at least in Canada but I'd imagine UK too, not a lot of sites seem to sell them to the general public.  I ended up buying mine on Amazon at a bit of a markup but shipping was free.  Some sites that DID sell them wanted like $300 to ship per module.   Avoid local hardware stores as they charge like 5x what you should pay.  Nearly identical 100w solar panels I got for $160 per unit were like $600 at Canadian Tire.  They went "on sale" for like $300 at one point which was still too expensive.   I find the rule of thumb is to try to pay under $1.5 per watt. 

I'm hoping with growing popularity we start to see more retailers stock them at reasonable market prices.

I don't think I would trust Ebay stuff though, but it's really hard to tell.  All solar panels are made in China anyway, so you could very well be buying the exact same panel done in the same factory as a name brand one, but for way cheaper.  I imagine lot of chinese factories will produce more product than the customer needs, so they can sell units themselves at a cheaper price under a different name.    Makes sense to me if you have all the tooling in place.
 

Offline Nauris

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Re: Quality of chinese Ebay solar panels vs reputable source?
« Reply #8 on: February 20, 2019, 06:12:12 pm »
100 Euros should get you a good quality aluminium framed 300W panel, not a 30W one. Your local supplier sounds like a rip off.

Last time I checked $0.3/watt was the bulk pricing of the bare solar cells, and the finished product was more like $1/watt. Where can you get a 300W panel for $100?
Here the going rate seems to be about 140 euros per 270W panel of decent quality and certainly no lack of sellers to choose from.
« Last Edit: February 20, 2019, 06:14:18 pm by Nauris »
 

Offline DougSpindler

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Re: Quality of chinese Ebay solar panels vs reputable source?
« Reply #9 on: February 22, 2019, 05:43:05 pm »
In the US there are a couple of companies selling excess panels from large commercial installations.  Meaning a contractor will have a contact to install say 926 panels.  But price wise it's more cost effective to by a lot of 1,000.  They sell the excess to a broker who then sells the 74 panels for a lot less than what “we” could ever buy them for.  What’s being sold are brand new, name brand panels and inverters.

 

Offline metrologist

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Re: Quality of chinese Ebay solar panels vs reputable source?
« Reply #10 on: February 22, 2019, 06:57:30 pm »
Hook us up! I think you are around SF?
 

Offline DougSpindler

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Re: Quality of chinese Ebay solar panels vs reputable source?
« Reply #11 on: February 23, 2019, 08:48:55 am »
There’s a compny in Florida which has a far amount of product in Nothern and Southern California.  Sorry cant remember the name, will have to look on my other computer.
« Last Edit: February 26, 2019, 10:48:01 am by DougSpindler »
 

Offline Freesurfer

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Re: Quality of chinese Ebay solar panels vs reputable source?
« Reply #12 on: February 26, 2019, 12:06:59 am »
george80:
I understand what you mean about "the more the better". But "more" also comes with a higher price tag, so the general rule I'm taught about sizing solar systems appropriately/cheapest for the purpose is "Enough battery storage to last for the entire stay" and "Enough solar power to recharge the batteries between each stay". (and of course margins, worst case conditions, longer stays or more frequent stays than usual have to be added in).

With a system powering a home you live at, it's a bit different as you are continously using power and need to replenish that just about every day, and often you can backfeed excess power back to the grid so no solar power is ever wasted.
For camping/cabin/cottage purposes, smaller panels may do fine as there may be several weeks between each stay. If the solar array is oversized it may only spent perhaps 10% of the duration recharging, and another 90% sitting idle. Not an ideal investment when you can downscale the array to 1/10 the size.  :)

And while I haven't done the exact maths, I don't think 120W worth of solar (assuming the panels are up to their rated spec) is all that outside the ballpark. :-)


I still think that ebay panels are going to be the cheapest option, even if they are not up to their rated spec. At least where I live, it's not possible to buy any panels in the price range that will ever repay themselves as there is just not a market for them here. It's not common for people to have roof mounted or grid tied systems installed in their homes, and people only use them in places where electricity is otherwise unavailable.
 

Offline george80

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Re: Quality of chinese Ebay solar panels vs reputable source?
« Reply #13 on: February 26, 2019, 07:37:45 am »
And while I haven't done the exact maths, I don't think 120W worth of solar (assuming the panels are up to their rated spec) is all that outside the ballpark. :-)

I have severe reservations about that low an input to the size battery banks you are proposing.  I think this will amount to no more than a trickle charge more suited to floating the batteries than charging them.

You comment about weeks between visits is entierly wrong. You NEVER want batteries sitting partially flat for weeks, may as well just use them for target practice and be done with it. the effect will be the same.  Spending 10% ( or  less) of their time is EXACTLY what you want.  If you look up anything about batteries, you will soon learn the faster you can recharge them and having them at float voltage the better.

Running them down and then having them still to reach full charge a week later will kill them sure as shooting them will.

I guess a lot would depend on which is cheaper for you, replace battery's every 6-12 Months or buy more panels. If you have a free/ cheap supply of battery's, then not to worry.  Where I am battery's are expensive and panels are cheap so my situation may not apply to your yours.

There is another practical and worthwhile soloution if not one seen as politically correct now days.  It's probably a filthy term but seeing some of us are grown up her.... It's called a Diesel generator.
Actually a diesel engine driving a car alternator will do just fine. Picked up a new 6 HP diesel the other day for $50  and an alternator wouldn't cost any more.  Bit of fabricobbling and you have all the power you want when you want it.  Hook it up to your batteries and you can run a big inverter all day and when you are finished the batteries will still be 100% Charged.  Solar panels will keep them floating and all is well and long lived with the world.

I built one of these setups and it works great. I over geared the alternator with a 6" pulley on the engine and a 2" on the alt and the engine only hast to fast Idle to provide real good power which keeps it quiet and uses minimal power.

You could use a petrol engine as well, you'd be lucky to use 2L of fuel a day,  so not worth worrying about.

 

Offline Freesurfer

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Re: Quality of chinese Ebay solar panels vs reputable source?
« Reply #14 on: March 03, 2019, 11:51:02 pm »

You comment about weeks between visits is entierly wrong. You NEVER want batteries sitting partially flat for weeks, may as well just use them for target practice and be done with it. the effect will be the same.  Spending 10% ( or  less) of their time is EXACTLY what you want.  If you look up anything about batteries, you will soon learn the faster you can recharge them and having them at float voltage the better.

Running them down and then having them still to reach full charge a week later will kill them sure as shooting them will.

I guess a lot would depend on which is cheaper for you, replace battery's every 6-12 Months or buy more panels. If you have a free/ cheap supply of battery's, then not to worry.  Where I am battery's are expensive and panels are cheap so my situation may not apply to your yours.

.....

You could use a petrol engine as well, you'd be lucky to use 2L of fuel a day,  so not worth worrying about.

You have some good points there about batteries being damaged sitting partially discharged for that long. So I will go with more than the suggested 120W.
I came across someone selling four used 60W panels locally from what would be our equivalent of "craigslist". So that's 240W in total.  I think I will be going with those for now, and if it turns out to be too little I can get more panels later. With some simple PWM charge controllers the panels may do 3-4A on a sunny day and recharge the entire battery bank (from completely empty) in 30-40 hours of perfect sunlight. Chances are the batteries won't be entirely drained either (they really shouldn't).

We already have a 2kW Honda petrol generator sitting there which can take some of the bigger loads. The last visit we had while working there for 3 days we consumed about 4-5 litres of petrol. The solar stuff and battery bank is just so the petrol generator doesn't keep us awake at night.
 


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