Anyone have 200-250W flexible solar panel that puts out over10amps

As I have a rear fold camper trailer I replaced my 120watt folding panel with a 160 watt flexible panel which I can sit on the bed when the camper is closed.
I recently went camping for the first time after the buy, and found that the maximum output was only 6 amps which was worse than my 120W folding panel.
In other words the 160watts was in reality only about 100.
When looking at Ebay for 200-240 watt panels the negative comments are full of "not really 200 watts"
Has anyone bought a 200-250watt solar panel which actually puts out over 10 amps? I would love to know the seller and brand.
Regards Philip A
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Reply By: Frank P (NSW) - Wednesday, May 22, 2019 at 17:19

Wednesday, May 22, 2019 at 17:19
As a very general rule you can expect only about 70%-75% of the commonly advertised panel wattage. If your panels wattage is rated at NOCT (Normal Operating Cell Temperature - not common as it generates a lower figure which doesn't look as good for the advertisers) you will get closer to the advertised figure.


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Reply By: RMD - Wednesday, May 22, 2019 at 20:07

Wednesday, May 22, 2019 at 20:07
With a solar panel it is rated at a working voltage and a working amperagee. Typically it is around 18v which is slightly under the open circuit voltage. With that, it is rated at a slightly lower amperage than when short circuited. That is ideal conditions and will be overstated in Amps by most makers.
The normal battery Amps registered by a PWM regulator/ammeter will be far Lower than expected because the regulator drags the voltage down to just above battery voltage. Therfore the potential difference is small and provides less flow of Amps.
With electronic smarts, an MPPT regulator holds the panel at a far higher voltage and permits the gathering of more energy. Since the available energy is a product of volts at a certain amp flow, ie, 18v and panel amps ability at the time, that energy is well above the normal registered into a battery. My setup can have 8amps flowing in the solar line at a higher voltage level and then the MPPT switching takes advantage of that higher level and around 11 amps are registered going into the battery.
So, depending on how and under what conditions you are operating, the results you see as energy product to charge a battery will vary.
Not sure what situation you are seeing/Measuring so hard to see what you are achieving. Just shorting the panel and measuring amps doesn't mean much.
AnswerID: 625678

Follow Up By: Rangiephil - Wednesday, May 22, 2019 at 21:11

Wednesday, May 22, 2019 at 21:11
I have a quality GSL MPPT 12amp controller placed near the battery 100AH wet deep cycle Century via 4gauge 10 metre leads..
I used to have a 120Watt folding glass panel which on a good day would output up to 7 (say 100watts at 14volts) amps and more often 6 on an inline watt/amp meter to my house battery .
I then bought what was supposed to be a 160watt flexible panel as the folding panel weighed a lot and took up lots of space below the bed in my camper.

To my dismay when I expected about 8amps max (8x14=110) out of the new panel , the most I have seen is 6 amps and generally 5 through exactly the same wiring.
I expect about 20-30% loss on the stated specs but not 40-50%!
It is apparently quite common for the specs of panels to be vastly exaggerated on Ebay. I am trying to find out the experience of others who have bought a 200watt plus panel. 10amps output is not a lot on a 200watt panel !10x14=140watts but the negative feedback on several sites suggests that even this may be optimistic.
Simple question who has bought a 200watt flexible panel and regularly sees over 10 amps from it? My impression is that few people have any idea what the output of their solar panel is but I thought I would ask . very few (none?) Australian reviews of different brands on Google.
Regards Philip A

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Reply By: Member - peter_mcc - Wednesday, May 22, 2019 at 21:38

Wednesday, May 22, 2019 at 21:38
As a rule of thumb most panels are about 17% efficient. Standard test conditions are 1000W/m2 of "light" - so 1m2 of panel should generate 170W.

Perhaps measure the area of the cells on your flexible panel (in m2) and see what the "real" rating is.

You can apply the same basic test to other panels online - work out the area in m2 (even if it is of the whole panel including borders) and multiply by 170 to get the approximate wattage. You will find lots of the eBay ones are over-rated, some by a huge amount.

You may have more luck with one of the bricks & mortar stores - my research recently showed their panels were close to realistic.

Alternatively if you've got the $$$ you can buy super tough flexible panels for marine applications but they are expensive. You get what you pay for I guess.

PS the 170W/m2 is a rule of thumb - some panels will be a bit more efficient. But it's highly unlikely that the cheap panel on eBay is 25% efficient... just not going to happen!

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Reply By: Iza B - Thursday, May 23, 2019 at 06:39

Thursday, May 23, 2019 at 06:39
What were the weather conditions when you went camping? Angle to the sun, sun's position in the arc, cloud, and temperature will affect the panel output. As others have said, certain lab conditions are set when panel output/rated wattage is reported by the manufacturer. Real world conditions do not replicate the lab conditions closely.

A quick confidence check would be to put you old and new panels side my side and check for the difference in performance between the panels.
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Reply By: Rangiephil - Thursday, May 23, 2019 at 08:25

Thursday, May 23, 2019 at 08:25
Thanks for your replies.
I have been using solar panels for many years and am pretty aware of their limitations.
What I was looking for is a real World recommendation of a supplier and hopefully brand based on personal experience.
I don't have the money to buy a Sunpower panel (with 22watts per sq m) so was looking for something "reasonable" .
I recall the time I wasted talking to a GSL tech about the biggest wattage panel that could be handled by the GSL 12amp MPPT , and was "advised" out of a 180watt panel. What a joke as most of the panels are just fairyland specs.
My current flexible panel is about 0.9sq m so even on the 17% efficiency yardstick it is pathetic.
Regards Philip A
AnswerID: 625687

Follow Up By: RMD - Thursday, May 23, 2019 at 08:43

Thursday, May 23, 2019 at 08:43
G"day Philip
I too have had panels for a long time but the performance is as you have stated. I work on the 200w panel being not quite 10 amps. I recently purposely bought some cheaper panels and have them in parallel. As you mentioned, to buy a top quality panel is %%%%'s.
The rating and actual output of these new cheap panels is only a small amount higher than the output of some decent panels of half the rating wattage. I don't think you can get around the issue without it costing quite a lot. I look at the 200 watt and divide the first two numbers by 2, so 10 amps if lucky.

Just a note with the wattmeter and an MPPT reg. I removed the wattmeter from my static system at home because it conflicts with the MPPT reg. While showing something the wattmeter must output a frequency into the line and the MPPT didn't like it and charging rates were affected, ie, charging slowed considerably. I use a clamp meter to check in that situation and it read higher than the wattmeter screen did. Maybe it doesn't happen with all devices but it fooled me for a while.
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Reply By: phantom - Thursday, May 23, 2019 at 10:22

Thursday, May 23, 2019 at 10:22
We have 2 by 120W Projecta solar blankets and can regularly get 15A (combined) out of them.
Not cheap but they work well and fold up to the size of a thin briefcase.
AnswerID: 625692

Reply By: swampy - Thursday, May 23, 2019 at 11:00

Thursday, May 23, 2019 at 11:00
To give u a base line I get [rigid glass panels ]
390w panels 2x 195 trifold sets , 1 x sharp mono , 1 x Kyocera poly
MPPT Tracer 30amp
battery at 40-50% discharged
26-29 amps
AnswerID: 625694

Follow Up By: Allan B (Sunshine Coast) - Thursday, May 23, 2019 at 14:31

Thursday, May 23, 2019 at 14:31
You could damn near run an electric drive-line on that lot Swampy. lol

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Follow Up By: swampy - Friday, May 24, 2019 at 09:20

Friday, May 24, 2019 at 09:20
1 x set fixed to camper roof
1x set portable
Peak amp output lasts around 2hrs or so because shifting sun and going into absorption mode . Even many single AGM 120amp will handle this.

Its a hard life when the battery [s] are charged quickly by smoko . This allows for plenty of delays/cloud .
Dont have to worry about electrical consumption to much . Mines only modest anyways.
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Reply By: Rangiephil - Thursday, May 23, 2019 at 14:54

Thursday, May 23, 2019 at 14:54
So I ended up buying a 250watt panel the dimensions of which (1100x990 ) suggest that it will output about 170watts .Thanks to the member who pointed out this rule of thumb. It is a cheapy but IMHO that doesn't matter as long as it generates.
Hopefully at that it will put out 9-10amps in ideal conditions.
I will now get some more aluminium edging and glue it around the perimeter to give it rigidity and transfer my aluminium stands that go in the holes.

It will fit flat on my bed along with my table.

I looked at glass panels , but their thickness would make it difficult maybe to close my camper and heavy, and the folding ones are enormous when opened up. I am damned if I know how to prop them up, and I could see myself running around shifting position to get sunlight every 10 minutes.
That 29 amp output certainly sounds like it would do the job, but probably blow up my poor old battery.
Regards Philip A
AnswerID: 625697

Follow Up By: Frank P (NSW) - Thursday, May 23, 2019 at 16:26

Thursday, May 23, 2019 at 16:26
Hey Rangiephil,

I was looking for an inexpensive and thin, lightweight setup like you. My 100 watt thin panels (x 2) were a discontinued item at Jaycar and came at the right price. They, along with my table, store upright with foam separators across the back of the storage unit in my ute.

To make them more robust when deployed I made a frame from 10mm square U section aluminium extrusion from Bunnings and pop rivetted it onto the panels.

I made the side stiffeners a bit taller to accommodate each end if needed.

With offcuts from the side stiffeners I made a hooked centre prop which is all that is needed most of the time. The prop goes behind the panel, which sits in the hook at the bottom.

The rear legs are 6mm solid round aluminium rod, again from Bunnings.

The panels are light enough to be blown over by the wind. If necessary I use a bit of cord tied into the centre hole at the top of the panel and bull it back against the centre prop to a peg in the ground.

With my unsophisticated PWM controller my 200 watts give me about 140 watts - the last I recall noting was 10 amps as the battery went into absorption at around 14.2 volts.


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Reply By: Rangiephil - Thursday, May 23, 2019 at 20:10

Thursday, May 23, 2019 at 20:10
Looks a good setup.
I made my frame from aluminium edging which is about 6MMx3MMx6MM, which I squeezed in to roughly match the thickness of the panel, then filled with Sikaflex all round. This keeps the panel thin so that the top of the camper has space to close.
It makes the panel quite stiff. My props are pretty much like yours.
I might put short legs on like yours as blades of grass can impinge on the bottom row of modules. Thanks for that idea.
Regards Philip A
AnswerID: 625706

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