Portable tropical solar

Submitted: Friday, Mar 31, 2017 at 19:40
ThreadID: 134573 Views:2205 Replies:5 FollowUps:6
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Hi all

just looking for some advice please.

Travelling to PNG soon and need to take a portable, low powered solar set up to run a few small electronic devices (slr camera, head torches and phones). We'll be there for a few weeks and then leave the set up with the locals when we return home.

We've settled on a 25w folding solar panel with 2 x usb outputs, 2 x powerbanks with usb input/output and usb powered battery chargers.

The advice I'm looking for is how to set up the panel for maximum efficiency and longevity in a harsh environment. The village we're staying in is on the coast so the environment is both humid and corrosive.

I thought it would be worthwhile to make up a lightweight rough aluminium frame to keep the cloth backed solar panel up out of the dirt. What angle is the most efficient to maximise charging? I read somewhere that the simple cheat is just an angle equal to the latitude - in this case that's around 10 degrees, but that seems like a pretty shallow angle?

Also, is there anything we can do to prolong the life of the usb ports and AAA/AA batteries? Maybe spray with something like Inox/Lanox or some other moisture blocker?

What about any treatment for the cloth backing of the solar panel? Does anyone know of a spray or other option to keep it from going mouldy in the tropics?

Thanks for your help, not exactly 'exploring oz'!


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Reply By: Motherhen - Friday, Mar 31, 2017 at 21:37

Friday, Mar 31, 2017 at 21:37
Apart from the harsh climatic conditions, remember that solar panels do not perform as well in the heat.
Motherhen

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AnswerID: 609832

Reply By: Les - PK Ranger - Friday, Mar 31, 2017 at 22:10

Friday, Mar 31, 2017 at 22:10
You are obviously setting this up in the village ,and basing there, going out during the day to photograph etc ?
Does the panel have a controller ?
Does it need one at that output ? Not sure.

It isn't overly hot up there, but yeah it's humid !

I don't think you'll have any issues with it is a few weeks though, or are you mostly worried about when you leave. and the locals will make use of it ?

They have good little setups on / in the roof spaces of many tiny family huts all over the country, and solar charging all sorts of old lead acid batteries, so think they'll manage ok.
They are mostly just using them to run simple 12v lighting in general, usually one room like a kitchen area.

What sort of powerbanks are you using (amp/hrs) ?
AnswerID: 609833

Follow Up By: leroy_od - Saturday, Apr 01, 2017 at 11:57

Saturday, Apr 01, 2017 at 11:57
Hi Les,

I don't think the panel has a controller, at that wattage I think it'd put out around 3 amps max. I only have one 9000mAh lithium powerbank so far, will get another about the same capacity or slightly larger before we head off.

Yes the concerns are mainly for the longer term use of the people there, we will leave battery powered lights, dive torches and phones (no electricity or running water but Digicel are expanding their phone network through that area).

I think in that environment the electronics/usb ports will be a worry.
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FollowupID: 879710

Follow Up By: Les - PK Ranger - Saturday, Apr 01, 2017 at 13:02

Saturday, Apr 01, 2017 at 13:02
Will one 9 amp/hr be ok for the days use, and you will leave one on charge while out ?
If so, should be ok to charge direct.

Are you on the mainland (north coast by chance ?) or one of the islands ?
We spent time on the north coast of PNG in 2008, Gona to Oro Bay, and also up around Lae and into the highlands / mountains.

On my to do list to head up to Rabaul (New Britain) and explore there sometime in the coming few years.
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FollowupID: 879712

Follow Up By: leroy_od - Saturday, Apr 01, 2017 at 19:41

Saturday, Apr 01, 2017 at 19:41
Hi again

we'll be on the eastern end of the mainland, Goodenough bay in Milne bay Province. Looking forward to experiencing a slower pace of life for a couple of weeks!

I've had only 1 day in Rabaul, but from the little I saw it would be well worth a look around, and the people there are very friendly. Try to make it to the local produce markets if you can, the lush volcanic soil makes for some great fresh tropical fruit!
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FollowupID: 879718

Follow Up By: Les - PK Ranger - Saturday, Apr 01, 2017 at 20:34

Saturday, Apr 01, 2017 at 20:34
Awesome, well off the beaten path down that way.
We looked at some coastal walking tracks from Oro Bay through to Milne Bay, but opted for part of our trip to the highlands, and Mt Wilhelm.

Take your Malaria meds religiously, before, during, after !!
I thought I did, but a mix up in scrip info saw me finish the after tablets a week early.
Nearly 18 months after returning, that's pretty much the full incubation period the larvae can be dormant for, it came out and gave me a damn good thrashing for a few weeks, before it was finally diagnosed and treated.

I reckon I picked it up in Oro Bay, that north coast is the best place for mossies.

Ah well, I can honestly say I had the full PNG experience :D
And after a clean nearly 7 years without reoccurance, it won't be back.
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FollowupID: 879721

Reply By: Member - Boobook - Saturday, Apr 01, 2017 at 10:06

Saturday, Apr 01, 2017 at 10:06
A couple of hopefully useful observations

PNG is almost at the equator so the sun is to the south in Autumn through Winter and Spring. 10 degrees to the south is probably about right.

I haven't been there but I guess it is tropical with much cloud cover, and would definity be hot. I would at least double the solar capacity to what you think as panels only put out 10 - 50 % of their power in those conditions.



AnswerID: 609836

Reply By: equinox - Saturday, Apr 01, 2017 at 21:55

Saturday, Apr 01, 2017 at 21:55
Hi,
I think best angle would be 90 degrees minus your latitude.
Cheers
Alan

Looking for adventure.
In whatever comes our way.
"Outback Yonder"


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AnswerID: 609842

Follow Up By: equinox - Saturday, Apr 01, 2017 at 22:35

Saturday, Apr 01, 2017 at 22:35
Having said that leaving it set up at 80 degrees from north (90 degrees minus 10 degrees latitude) would be optimal for a fixed set up only.

To have an adjustable unit which allows for the seasonal movements of the sun I suggest the following:

For time of winter solstice (June) take the angle of the earth which is 23.5 degrees from the equinox figure of 80 degrees. This figure is 56.5 degrees from north horizon. So angle the solar at this angle in June.

For summer solstice add 23.5 to the 80 degrees. This is 103.5 degrees from north which is 76.5 degrees from south. Use this angle in December.

Use the 80 degree angle for March and September.

Looking for adventure.
In whatever comes our way.
"Outback Yonder"


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Reply By: Member - John M50 - Monday, Apr 03, 2017 at 18:42

Monday, Apr 03, 2017 at 18:42
Solar works fine in PNG. I work in PNG and we use solar in our remote locations. There are two issues, locals "Borrow " the solar panels and they don't work under the jungle canopy.
Do not leave your solar panel unattended, it will go walkabout quickly.
Great people and will appreciate your giving them the solar when you leave.
Have a great trip, it is a wonderful country and people, please be aware of your surroundings and security.
AnswerID: 609892

Follow Up By: leroy_od - Monday, Apr 03, 2017 at 19:08

Monday, Apr 03, 2017 at 19:08
Thanks John, will take care and make sure we have fun too.
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