Sunmaxx 300Watt Solar blanket

pghollis · Veteran Member

Sunmaxx 300Watt Solar blanket

Whenarewethere · Guru

There is a basic dimensional error of packed size in relation to open size on their website so I wouldn't have bought it from that point alone.

Since you have it have you calculated the actual surface area & multiplied that by let's say 0.15 (150 watts per square metre).

pghollis · Veteran Member

Just worked out the surface area.... its 1.716 square meters. So if we multiply by 150 watts we get 257, which is reasonable (its not 300, but its better than 59).

Whenarewethere · Guru

Is it absolutely square to the sun, elevated so it stays cool, is it perfect weather, not a single tiny section anywhere that has a shadow?

pghollis · Veteran Member

Well it was pretty close to being directly at the sun. It would have been more directed at the sun than the 170watt panel on the van roof would have been.

pghollis · Veteran Member

Well I managed to get a refund for this blanket and Sunmaxx let me keep the faulty one. They have removed these blankets from sale. So since I had the blanket I thought i'd just do some more testing on in (i.e. cutting slits in the material between each panel to expose the connecting wires). It is basically just 8 panels connected in parallel. I was hoping that there was just a loose connection that was disconnecting a few of the panels, but my measurements were as follows:

Cell # Volts Amps Watts
1       20.8   0.27   5.616
2       0        0         0
3       20.56 0.38   7.8128
4       20.1   0.31   6.231
5       19.8   0.49   9.702
6       19.96 0.4     7.984
7       19.95 0.33   6.5835
8       19.93 0.27   5.3811

Total 20.05 2.45 49.1225

For this to be a 300Watt blanket I would expect to be seeing around 1.8 - 1.9 Amps @ 20.05V for each cell.

Must give Sunmaxx credit that they were quick to respond and try to help and did not mess around with a refund.

-- Edited by pghollis on Tuesday 15th of September 2020 03:34:21 PM

dorian · Guru

From the web site ...

max power current = 16.66A

The max power is then 290W.

The surface area (not allowing for borders) is 2130mm x 675mm = 1.438 sq m

At 160W per sq m, that's an output of 230W.

The panel would have to have an efficiency of 20% to produce 290W from 1.44 sq m.

Here is their 250W panel:

https://sunmaxx.com.au/products/250w-solar-blanket-kit-t2

1270mm x 720mm = 0.914 sq m

That corresponds to an output of 273W / sq m, which implies an efficiency of 27%.

Clearly that's bogus.

Personally, I would avoid this supplier.

Another one ...

https://sunmaxx.com.au/products/sunmaxx-100w-fixed-solar-panel

max power current = 5.11A

max power voltage = 16.5V

Therefore the max power wattage is 5.11A x 16.5V = 84.3W

Area = 640mm x 680mm = 0.435 sq m

Efficiency = 84.3 / 0.435 = 193W / sq m = 19%

This panel is claimed to produce 200W from 1350mm x 540mm:

https://sunmaxx.com.au/products/200w-folding-solar-panel-kit-t

That's an efficiency of 27.4%.

-- Edited by dorian on Wednesday 16th of September 2020 05:43:24 AM

Whenarewethere · Guru

pghollis wrote:
Cell # Volts Amps Watts
1       20.8   0.27   5.616
2       0        0         0
3       20.56 0.38   7.8128
4       20.1   0.31   6.231
5       19.8   0.49   9.702
6       19.96 0.4     7.984
7       19.95 0.33   6.5835
8       19.93 0.27   5.3811

Total 20.05 2.45 49.1225

These panels are all over the place from terrible to abysmal, & on top of it 1 doesn't work. Even the best panel x 8 would only be 77 watts.

Since you got a refund quickly. I would let them know what you found. It may help them with their supplier.

pghollis · Veteran Member

When I purchased the blanket I honestly wasn't expecting to get 300w out of it. I would have been happy with 200w (of course if I did get 300w it would be a bonus). But to only get 50-60w was quite disappointing. Anyway, I have my money back to spend on another panel, which hopefully will be a bit better.

I did provide the supplier with my findings after I did the autopsy on the of the blanket, but got no reply from them :)

Whenarewethere · Guru

If you have a bit more space or have a space that a solar panel has to fit in why don't you knock up your own portable unit. It's not difficult & you get exactly why you want.

That's what I did & it works brilliantly.

https://thegreynomads.activeboard.com/t65231112/custom-6x20-watts-solar-setup-with-mppt/

McGuckian · Newbie

The blanket you tested is almost identical to the Maxpro brand marketed by Outbax and through Catch. I bought a so-called 250watt blanket. On testing it was more like 120watt at best. Returned it and got a refund.

-- Edited by McGuckian on Monday 5th of October 2020 05:25:25 PM

orid · Senior Member

I purchase a 200 watt blanket from Bcf. Good quality .Puts out 11 amps through my dc to dc charger . In case this helps

orid · Senior Member

The make wasXTM. $359 Regards Orid

Jaahn · Guru

orid wrote:
I purchase a 200 watt blanket from Bcf. Good quality .Puts out 11 amps through my dc to dc charger . In case this helps

Hi orid smile

Thanks for the info ! Just a comment and not to be critical. That 11A is well short of 200W !

11A x 14V (to be generous) is only 154W.

My suggestion is to just get some real panels and make up something that works as it should and for much less cost.

Jaahn

Whenarewethere · Guru

I don't get it why people willingly accept that solar panels under perform, but with other products they scream blue murder if it not up to scratch.

If anything, one is in the middle of nowhere, you have calculated your requirements & a solid margin, & one burdens oneself with crap solar panels.

Do it right once!

dorian · Guru

orid wrote:
The make wasXTM. $359 Regards Orid

If you mean this $360 panel, there is virtually no product info. I wouldn't have bought it without further clarification.

https://www.bcf.com.au/p/xtm-200w-folding-solar-blanket/578269.html

Can you tell us the dimensions of each panel?

-- Edited by dorian on Tuesday 6th of October 2020 06:05:53 PM