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Atem Power 250W solar panel is a dud

April 24, 2019 — BarryK

I posted about a 250W folding solar panel that I purchased from Vicoffroad, via eBay:

http://bkhome.org/news/201904/large-250w-solar-panel-for-camping.html

Very cheap, only AU$288 including delivery.

It arrived a couple of days ago. The sky was a bit murky yesterday, but today brilliant sunshine, totally blue sky, not even a wisp of cloud, ambient temperature cool, low 20s, location Perth WA, date Wednesday April 24 2019. I set it up about 10.00am, but was only getting about half of the expected current. Hmmm.

I am a retired electronic engineer, and I once worked in solar energy research, so I am competent in this field. Of course, I had to investigate further. This is a folding panel, and each side has a junction box. It is easy to pop off the covers by inserting a screwdriver:

img5

Standing at the back of the panel, this is inside of the right-hand junction box:

dud4

...the left-hand panel is connected in parallel to the right-hand panel, and output then goes to the solar regulator:

img3

...what I have done here is removed the wires from the regulator, bypassing the regulator. The solar panel now goes directly to the output cable. At the other end of the cable I used nichrome wire as a resistive load. A 150A current-voltage-power meter is plugged in:

img2

I used a digital multimeter to confirm that the in-line 150A meter was reasonably accurate, yes it is. That is also a recent purchase, so at least that works!

The peak-power point was somewhere between 18.55V @ 5.65A (104.8W) and 16.87V @ 7.08A (119.7W). Yep, only about half what is should be. Obvious next step is to separate the panels. I disconnected both panels:

img6

...with a jumper lead, I can now connect either panel to the load.

The right-hand panel gives about 3.5A at the peak power point. Drawing more, bringing it down to 11.64V get 4.69A.

The left-hand panel also gives about 3.5A at peak-power, and I loaded it some more, down to 10.98V at 4.69A.

As a final check, I also measured the short-circuit current out of each side, directly on the junction-box terminals, and yeah, only about 4.7A from each (measured mid-afternoon, with the sun a bit lower in the sky. Midday it would have been a tad higher).

So, yeah, they are crap panels, giving less than half of that claimed. They have labels on the back of each side, stating peak power at 18.4V @ 6.8A and short-circuit current of 7.09A.

What really bothers me about this, is that most people would not know. They would connect the panel to the battery, using the supplied crocodile clips, and think it is working. Well it is, except they are getting far less power than advertised.

The problem is, this overstating of power output is endemic to many of the cheap panels from China. What to do? Something should be done, I should report this somewhere, but what government dept would be appropriate?
The panel that I purchased was from an Australian business, and they have an obligation not to do false advertising. 

Tags: nomad

Planning a DIY solar water distiller

April 23, 2019 — BarryK

I posted recently about this Carocell 1000 solar water distiller, that was given to me about five years ago:

http://bkhome.org/news/201904/fcubed-solar-water-distiller.html

The problem is the size, 1.1m x 1.1m. I would need a roof rack, and preferably slide it under the rack, so would have to buy a roof rack with 45mm clearance above the roof. Well, there is such a roof rack, but currently that is the only purpose that I have for the roof rack.

I plan to create a shelving system in the back of the car, and can have a shelf into which a solar water panel can slide. But the width of the back door is only about 1m, too narrow for the Carocell.

So, playing with ideas for building my own. It will be a flat panel, with water trickle-down, through a cloth. I have ordered a special eco-friendly cloth to test, and also have corresponded with a chap in the US who has made a similar type of trickle-down panel. He advised a certain cloth that I could try.

I was thinking of making the frame from pine, pure pine, nothing laminated or chipboard. The danger is chemicals evaporating in the hot wet conditions inside the panel. But then, should the wood be left bare, or painted? If painted, same problem with dangerous chemicals.

It would be good to seal the surface of the wood, but it would have to be a "safe" product. I have asked for a recommendation on the "Green tech" thread of the Whirlpool forum:

https://forums.whirlpool.net.au/thread/2797034

Don't know if anyone will reply. Might have to take a punt on some product. Or, make the frame from aluminium. 

Tags: nomad

Food from the ocean

April 15, 2019 — BarryK

My last camping trip, early 2019, was to the South Coast of Western Australia, a campsite managed by DPAW (Department of Parks and Wildlife), accessed by a very corrugated dirt road. No water, no power, no phone signal. I loved it.

Many who go to these places are fishermen (and women), but as I am a vegetarian, I have wondered what food I could source from the ocean.

Shellfish possibly. Some vegetarians consider these OK to eat, as they are barely rated as animals, not having a spinal cord. They are considered to be "plants that move". Hmmm, don't know.

Then there's seaweed. Apparently, most of the seaweed that washes up on our shores is edible. I do ask myself, though, if it is edible, why haven't the fish eaten it?

This webpage has some useful info:

https://www.milkwood.net/2016/06/06/foraging-drying-using-seaweed-australia/

Ah, recognise this, kelp, all over the place at beaches:

img1

That page states that live seaweed cannot be collected, only dead. That is in NSW, but I saw on this webpage, the same applies to WA:

https://www.scribd.com/doc/313836965/Seaweeds-Australia-Newsletter-Issue-3-2-Nov-2013

Licenses are required from both the Department of Parks and Wildlife and the Department of Fisheries for personal and commercial collections of live seaweed (an Other Prescribed Purposes Licence). Permission from the relevant land manager/s (e.g. local govern-ment authority) is also required. However, dead beach-cast seaweed is not protected and if only dead sea-weed is being collected and it is not being removed from a marine reserve, then no license or authorisation is required. However, another separate department, the Department of Environment and Regulation should be contacted to ensure that one does not undertake activi-ties that may constitute ‘clearing’ under the Environ-mental Protection (Clearing of Native Vegetation) Regu-lations 2004 made under the Environmental Protection  Act 1986.

I hunted, could not find information on those licenses. A search of Dept. of Fisheries returned zero hits for "seaweed" ...hmmm.

The problem with dead seaweed is that it rots. You would need to be able to identify freshly-dead seaweed. A bit like collecting road-kill!

This blog post is in a new category, "nomad", and there is also a new section on my website, http://bkhome.org/nomad/ 

EDIT 2019-04-16:
I found the "Other Prescribed Purposes Licence" form:

https://www.dpaw.wa.gov.au/images/documents/plants-animals/licences-permits/Flora/forms/App_-_Scientific_or_Other_Prescribed_Purposes_Licence.pdf

...doesn't look like DPAW will smile kindly on an individual wanting to collect live seaweed for eating!  A licence is valid for 1 year and costs AU$10. Here is some more information:

http://www.licence.smallbusiness.wa.gov.au/BusinessLicenceFinder/prod/licence/7756

...what about the "personal enjoyment" category? img2

Tags: nomad