Recommended supplier for Flexible Solar panels please

Grandad5 · Senior Member

Recommended supplier for Flexible Solar panels please

Phillipn · Guru

Grandad5 wrote:
Title of the thread says it all with the possible exception of saying they'll be supplying a lithium setup.
I've always considered Solar4RV to be the recommended supplier but i'm seeing numerous options on evilBay for 'around' the $1 per watt (roughly) price tag.
I don't want attached controllers if possible and don't require any cabling with them.
Can anyone recommend one of the evilBay shops, or someone else please?
Jim

-- Edited by Grandad5 on Thursday 20th of September 2018 04:52:17 PM

Check out Solar Camping Australia in Hervey Bay. I got some LED lights from them a week or two ago, I checked out their semi flexable panels, they look quite good. The panels are made in USA.

www.solarcampingaustralia.com.au

Ph 0741249394

Cost a bit more, but remember "you pay with peanuts , you get monkeys".

-- Edited by Phillipn on Friday 21st of September 2018 07:05:28 AM

Grandad5 · Senior Member

Thank you Phillip

Peter_n_Margaret · Guru

Phillipn wrote:

The panels are made in USA.

Most unlikely. Their web site says that the cells are made in USA (which is likely). The panels will most likely be made in China.

You can also buy direct from a Chinese panel manufacturer (who uses premium USA made cells).

http://www.shinesolartech.com/goods/detail/1.htm

Cheers,

Peter

Phillipn · Guru

Peter_n_Margaret wrote:
Phillipn wrote:
The panels are made in USA.
Most unlikely. Their web site says that the cells are made in USA (which is likely). The panels will most likely be made in China.
You can also buy direct from a Chinese panel manufacturer (who uses premium USA made cells).
http://www.shinesolartech.com/goods/detail/1.htm
Cheers,
Peter

Make a call to solar camping and ask them where their panels come from.

Peter_n_Margaret · Guru

Phillipn wrote:

Make a call to solar camping and ask them where their panels come from.

I am buying direct from the panel manufacturer after discussions about exactly what cells and construction is used.

Cheers,

Peter

Grandad5 · Senior Member

Thank you Peter

EDIT: I hadn't followed your link when i posted to thank you.
Now I have and have discovered I was maybe under a misconception. I've been looking at 'Flexible" panels and now see there are also 'Semi-Flexible' panels.

So, what's the difference? Which ones do people generally use on caravan roofs?
You can see in my avatar why I'm considering flexible.

Jim

-- Edited by Grandad5 on Friday 21st of September 2018 03:03:46 PM

Peter_n_Margaret · Guru

Semi flexible would be the appropriate choice for your application.
Good ones will bend through 90 degrees maximum over the length of the panel.
Cheers,
Peter

Phillipn · Guru

Peter_n_Margaret wrote:
Phillipn wrote:

Make a call to solar camping and ask them where their panels come from.
I am buying direct from the panel manufacturer after discussions about exactly what cells and construction is used.
Cheers,
Peter

Who is the panel manufacturer that you are getting your panels from?

Peter_n_Margaret · Guru

Who is the panel manufacturer that you are getting your panels from?

I already posted that.

Cheers,

Peter

T1 Terry · Guru

What ever semi flexible panels you use, they will need a blocking diode in the positive lead if you are fitting more than one of them. I wouldn't recommend connecting them in series, the junctions are designed to have very little voltage drop across them and this results in very little back resistance to back low as well and this kills the panel.

T1 Terry

Grandad5 · Senior Member

Thank you Terry,

Got it, connect in parallel. Will do.

Is a blocking diode something that can be retrofitted if the panel doesn't have one or is retrofitting something one always does as panels usually doesn't have one?

And question 2. I recall hearing that there is a maximum Vmp that I should look for with lithium.

I have a very vague memory of you suggesting a 100W panel 'talks' to lithium better than say a 130W. Excess voltage is good for AGM but wasted on lithium.

How is my memory working?

If it is working, what max Vmp would you recommend?

Thank you
Jim

Peter_n_Margaret · Guru

Whether you connect in parallel or series depends on the panels you choose and on the regulator you use.
It is not a question of whether the panels are rigid or semi flexible, but a question of panel voltage and battery voltage and regulator choice.
Smaller panels in parallel will give better shade tolerance. All panels in parallel irrespective of whether they are rigid or semi flexible will need blocking diodes which are easily retrofitted if they are not supplied with the panel.
Ask Terry exactly which panels he supplies and where he gets them from.
Cheers,
Peter

-- Edited by Peter_n_Margaret on Saturday 22nd of September 2018 01:32:47 PM

T1 Terry · Guru

Hi Jim, the last panels I can remember having blocking diodes fitted were the Energex brand that were later bought out by BP solar and the blocking diode went by the wayside. Easiest to fit the blocking diode at the MC4 positive connector end. Punch the pin out of the plastic holder and either:
cut the wire and solder the diode non silver strip end to the panel end and the male pin from the plastic plug to the strip end so you can plug a female MC4 connector in that is part of the extension cable to the junction block
or
cut the MC4 connector off altogether and solder the non strip end of the diode to the panel end of the positive cable and the striped end to the extension cable.

If you do use the MC4 connectors you do need to punch the pins out so you can plug them together to their full depth to get the max contact area, then solder that joint to make sure it doesn't come undone and has minimal resistance. MC4 connector cause more solar problem than you can believe and are the major culprit for early panel death even in rigid panels.
The Vmp for a 12v lithium battery can be anywhere from 16vdc to 18vdc, a waste of solar energy if higher than that and that last bit to 100% SOC can be a tad slow in the hot summer sun if much lower than 16v STC (25*C panel temp not ambient temp)

T1 Terry

Grandad5 · Senior Member

Thanks heaps to both Peter and Terry.

Peter: "Smaller panels in parallel will give better shade tolerance."
That's a good enough reason to do it right there. Especially with my 'anything-but-flat' roof
Thank you.
(btw Peter. Can you try to refrain from posting pictures of your Oka please? My jealousy levels rise another notch each time. It's such an incredible rig. Nah... on second thoughts. Keep posting pics. I have learnt a trick or two looking at them)

Terry: So my memory is working. Hallelujah! Miracles never cease.
I've noted your suggestions. All taken on board.
Thank you

T1 Terry · Guru

Peter_n_Margaret wrote:
Whether you connect in parallel or series depends on the panels you choose and on the regulator you use.
It is not a question of whether the panels are rigid or semi flexible, but a question of panel voltage and battery voltage and regulator choice.
Smaller panels in parallel will give better shade tolerance. All panels in parallel irrespective of whether they are rigid or semi flexible will need blocking diodes which are easily retrofitted if they are not supplied with the panel.
Ask Terry exactly which panels he supplies and where he gets them from.
Cheers,
Peter

-- Edited by Peter_n_Margaret on Saturday 22nd of September 2018 01:32:47 PM

Hi Peter, series or parallel is a choice you can make with rigid panels, but not with the semi flexible panels. The way the 2 types of panel are constructed and the junctions used are different and a 12v nom semi flexible panel will not last very long with an open circuit voltage much higher than the 21v, 2 panels in series would produce 42vdc open circuit ... for a little while anyway wink

Learnt all this the hard way, via the back pocket after having to replace quite a few panels and at one point travel to WA to do one set. I'm sharing this information here at no charge to save others going through the same financial pain we went through. Add to that, the panels were a lot more expensive back then, I'm guess the price drop is due to attempting to clear them because the sellers have had so many claims regarding panel failures. Most sellers no add something about not connecting their panels in series or parallel or the warranty will be void, just to cover their butts

T1 Terry

Peter_n_Margaret · Guru

The manufacturer I linked to quotes...

maximum system voltage, @@600V

That is a tad over 42V biggrin

Cheers,

Peter

T1 Terry · Guru

Peter_n_Margaret wrote:
The manufacturer I linked to quotes...
maximum system voltage, @@600V
That is a tad over 42V
Cheers,
Peter

I can't seem to find that in the semi flexible panel section Peter, so I've emailed them for clarification and I'll post the reply when it comes.

T1 Terry

Peter_n_Margaret · Guru

Any response from Rooka yet Terry?
We found that she responded to our questions very promptly.
Cheers,
Peter

T1 Terry · Guru

Peter_n_Margaret wrote:
Any response from Rooka yet Terry?
We found that she responded to our questions very promptly.
Cheers,
Peter

It appears they had a festival holiday of some sort, but I did get a reply yesterday. I see there was a Julian in the Australian feedback list, any connection? wink

Yes, Rooka confirmed the 600vdc system capacity and the 5 yr replacement guarantee so they are certainly the exception rather than the rule. Even the panels sold by solar4rv now come with the requirement for blocking diodes to be installed if more than 1 panel in the solar array and no series connection.

So, thank you for the link and we will be making further enquiries. I see Rooka says they have been making these panels for 5 yrs, so no end of life is known as yet, but the 5 yr warranty verses the 12 mth warranty offered by other manufacturers and resellers is a real plus. I've asked my China contact to investigate/negotiate further regarding establishing a supply chain. Haven't heard back yet but I guess the whole holiday thing has turned things on their head over there for a while.

T1 Terry