Cheap PV panels

[horsall]

Hello All
I thought I would just post this link for cheap PV panels

www.ebay.co.uk/itm/300851710564?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

They look good value to me but I do wonder why they were all taken out of service?

But most panel are rated at 10/20 years life @ 80% output.

I am very tempted to add some more panels to our system

Roger

ps the people accepted a £70 offer if you look in sales so even cheaper

[caveman]

They look like good value. I would question why they came out of service and it looks like there were an awful lot them in service. There are made a big company in China and while they are not regarded as top of the heap they are ok and there are plenty of them in service around the world. I have 1kW of Trina panels and they have the same life expectancy. I would not worry about the lack of guarantee - few if any of these outfits will be around in 5 years let alone 25 years. I suppose if you got a spare or 2 you would be safe enough. I am tempted. Cye has a good nose for this sort of deal. He might post a view on this.

[cye]

well i have a nose caveman & i am often forced to follow it, but where it leads who knows...

look at the vendor. the address is dominica island, one of the west indies. initially i was suspicious. then i see is a huge american power outfit called 'duke energy' who own pv farms all over arizona and dotted around south america. could this be the same outfit?

'duke entertainment ltd' has its name on a solar (thermal) patent application UK 2478973. These guys are in the trade and not fly by night. perhaps the panels are slightly out of spec for some big pv farm, where careful balance in long strings is important. the yellowing of the background material may cause the panels to heat up a little more and lose a little efficiency? may be more of an issue in dominica than here? the buyer is usually well protected by paypal.

[cye again]

the name of the guy on the patent alongside duke entertainment is Michael Gooden.

He runs this eco festival outfit, and strangely they sell these familiar looking panels here:

solar.bimbleinn.com/

[cye]

and here's a pic of the stock they have for them,

and here's the spec...

shop.dukeent.net/image/nbsolarspec.pdf

these are not 12v panels. the OCV is about 45v and rated for 36v

can any old inverter or charge controller handle these?

Attachments:

[caveman]

You can get <1kW MPPT controllers with inputs of 150 volts and outputs to 12 and 24 volt battery banks. So you could install these panels 3 in series and these in parallel with 3 more in series and so on until you have enough. The higher the voltage you use to get from the panels to the controller the lower the losses in a given size of cable.

[cye again]

it's £115 delivery to NI for the first panel and then (I think) £3 per panel thereafter, so if a bunch of folks are interested would could bunch up.........

or a pallet of them (22 in a pallet) if there's a great demand.

any interest on the island of ireland?

[campbeji]

I'd be interested, but not a lot of money at the mo.

He's selling these at £79 on ebay but accepted an offer of £70 on a couple of occassions, a drop of £9.00. On his website he is selling them for £75 each, £4 less than ebay, probably because of the ebay fees, so if he still accepted an offer of £9 per panel off, that would be £66, and a further 5% off for a bank transfer would take it down to £62.70, if we buy a larger quantity, he may do it for less, £60 per panel or less.

We would need to see if he has a guarantee on them, from the point of view of sucessful delivery, or at least insurance, one good whack from a forklift and we'll be making solar panel mosaic.

[campbeji]

Hi, I found this today

www.globalstocksupplies.co.uk/viewstockitem/sharp-solar-panels

They are selling Sharp solar panels, inverters, roof mounting kits and fittings, there is no price but the company is a stock clearance outfit and probably bought it in at pennies on the pound so might be open to an offer.

Any thoughts.

[cye]

Roger

The panels you originally pointed out to us are still available. A few of us are interested in them here in Ireland.

They are for sale here
shop.dukeent.net/nbsolar and also still on eBay, and it seems they can be bought for £70-75ish on the guy's ebay shop.

Let's say someone had two or three of them and didn't want to grid tie them, maybe just use them to maintain batteries for household LED lighting and other low load work, how would one go about sizing a suitable battery bank for say 2 or 3 of these panels? Any particular mppt charger you would recommend?

Finally, the same vendor sells used deep cycle batteries on the shop.dukeent.net site. Are these a waste of time considering?

Many thanks

Cye

[horsall]

Hello Cye
The panels still look cheap.

Battery sizing all depends on how many days power you require with no sun input and also you don,t want the batteries to big or you may never charge then to full capacity.

MPPT charge controllers do give more power to the battery as they match the charge voltage to what is required and available, They do tend to work better when batteries require baulk charging voltage not absorb or float voltage.

When buying a charge controller make sure it is future proof and take as higher voltage as you are likely subject it to, Higher voltage tend to be better because the MPPT is more efficient.

We have an outback system but they are not cheap but they seem to have a good name and they replaced a faulty Mate3 unit in just over a week direct from USA at no cost what so ever to us, All kit comes with a 5 year warranty.

And as you probably know solar panels work better if they are cool, I find I get best output on nice sunny days but a cool wind blowing but then ours are not roof mounted so can cool better.

As to batteries it is always difficult as good ones are ALWAYS expensive leisure batteries have a limited life, it is all to do with how deep you can discharge them and number of cycles, I suppose you just have to ask for the specs and research the web and find the ones that suit your pocket and requirements.

Roger

[cye]

Roger, Thanks for this.

The battery bit is somewhat of a dilemma for me. On the one hand, whilst a large battery bank capable of storing more energy than may be required, oversizing the battery bank can be used to limit the depth of discharge and prolong the battery life?

Let's say I needed 1440watt hours lighting per night, that's 120ah from a 12v battery. Let's also say there is a choice of a 480ah battery bank or doubling up to a 960ah battery bank, giving us daily DODs of 25% and 12.5% respectively per battery option. The bigger battery bank will have a longer useful life (more charge/discharge cycles) because the DOD is less. Is it just a simple case of it (the larger battery option) will last twice as long as the 480ah battery bank, or is this 'useful life' versus DOD relationship not a linear one?

With my intended application I guess I would be sizing the battery bank to a minimum size based on expected 'good weather' daily input, with E7 or genny or similar topping up the poor weather shortfall if required. So, say 2 X175w peak of panels, would give say 1400 watt hours on an average summers day?How would that sit with a 480 or a 960ah 12v battery bank?

I am probably thinking about this all back to front, so grateful for any pointers regarding ballpark options.

Thanks

Cye

[horsall]

Hello Cye
Are you going for a 12volt system?

We have a 24volt system, 12volt is ok but cable sizing gets a bit big if you want to draw a lot of power at one time, so you can run smaller cables without voltage drop at 24 volt or 36v or even 48v.

I would tend to go for at least a 24volt system and use those small voltage regulators I gave you a link to, to run your led lighting as you will get a more stable supply.

We have a 1120amp/hr battery bank @ 24volt which is split into 2 560a/hr banks with a switch that combines them so I can use both banks or use one when servicing the batteries or to equalize them.

Our solar panel output is 1Kw @ 24volt plus what the wind turbines feel like adding(1 is broken at the moment) it some times goes to 1.1KW in favorable conditions when the MPPT is at peak efficiency.

Our generators ran for a total of about 200hours over the winter 6 months so about 1 hour a day average and the most the inbuilt battery charger can give is 80amp.

But as you know the secret is not making the power but not wasting it ie things on standby,lights left on etc

Roger