Solar power tests (again)

[BarryK]

I tested some solar panels and battery-banks back in 2014, and posted to this forum:

http://bushwalk.com/forum/viewtopic.php?f=21&t=18151

I have started another round of tests, this time focusing on ultra-light traveling, using a very small panel charging my smartphone directly, no intermediate battery-bank.

It's a work-in-progress, but good result so far:

http://barryk.org/light/solar/panels-small-2016.htm

The last post to the forum thread in 2014 commented that USB cables have very thin wires, with significant power loss.
Yeah, I have been cutting some cables, as I have wanted to use just one plug or socket, the other end wires soldered into my test circuit. I have been appalled how thin the wires are -- yesterday I chopped one with a thick cable, thinking that the wires should have a decent amount of copper in them, but no, the thickness was due to extremely thick plastic -- I guess that it is cheaper to use plastic rather than copper, and just make the cables look like they have thick wires.

[michael_p]

Are you the BarryK of Puppy Linux fame?

[BarryK]

Are you the BarryK of Puppy Linux fame?

Yeah, that's me

Puppy Linux was my thing, from version 1.0 released in 2003, up until 2013 when I started to let others take the lead. Just recently I handed over the domain names puppylinux.com and puppylinux.org to Mick Amadio (01micko on the Puppy Forum), so I am now fully retired from Puppy Linux development.

Though, I still dabble with a fork of Puppy called Quirky Linux, exploring some interesting ideas.

Anyway, my profession was electronic engineer, and even worked in solar energy research briefly. In my dotage, I have resurrected my interest in solar power, in the context of light-weight traveling. Just having fun.

[michael_p]

Wow. I'm a big fan of Puppy. It has helped me save a number of window$ computers over the years. Easily the best lightweight distro by a country mile.

I've been a full time linux user for well over a decade now. As a challenge I decided to try using Puppy as my desktop. I've been using it for several months now and it has been a very interesting experience. Even though it has been good I will probably move back to Ubuntu when 16.04 is released.

I just wanted to say thanks for creating Puppy Linux.

Back on topic.

The poor quality of cheap usb cables is no surprise. Try scraping the bare wire and see if it is actually plated aluminium wire. This apparently is a common technique used to make cheaper aluminium wire appear as if it is copper. I had a look at youtube but I can't find the video where someone actually did scrap some wire and discovered it was coated aluminium.

Keep up the research on lightweight (I see a theme here) solar gear.

Cheers,
Michael.

[keithy]

Good info Barry. I was the one mentioning the crap USB cables I discovered when testing my own solar kit in your other post.

Have you seen any of the newer higher efficiency solar panels that are out there now? The ones that claim 23% efficiency? My current panels are <15% efficiency, but over at candlepowerforums some people have been testing out the smaller 6.5W panels from Sunkingdom (through Amazon) and say that for their size/weight they are pretty good. They seem more powerful than my 7W GoalZero panel and smaller/lighter.

At around 250grams for the 6.5W, it might be a bit heavy for you, but apparently the output is quite good.

One of the guys over in that thread also has the 5W panel which was meant to be quite good as well.

I've just ordered a newer high efficiency 13W panel replaced my Goal Zero 7W and my Mercury 10W panels, but it hasn't arrived yet. The weight is about the same as my older 7W panel.

Regarding cables - There are some really crap cables out there. I originally used a spliced franken USB cable and my multimeter to sort through my crap slow charging cables, but I now use a USB meter to do this. I was originally doing this to see the current outputs of my panels, but when using testing it on my various USB cables I was surprised to see the difference in cable quality. You really can't tell from external appearances. Like you said, a thicker cable might only be thicker shielding/plastic rather than copper. And I found that even some manufacturer supplied cables like those provided with better branded phones and tablets aren't always the best either.

There are some better cables out there now thankfully. These can charge my higher current devices at up to or over 2A. I've picked up some very short 20cm Blitzwolf branded micro USB cables that are great, and have a couple of their 1M micro USB cables as well and they are also good at charging at higher currents.

PS. Thanks for Puppy Linux! I haven't played with it for a while, but had it on a netbook a while back.

[BarryK]

keithy,
Yes, I discovered those Sunkingdom panels yesterday.

Yesterday I updated my web page with a test of a 5W panel from DealExtreme, model SE05, which Sunkingdom also sell. It's a great panel, suitable for direct-charging a smartphone out-of-the-box:

http://barryk.org/light/solar/panels-small-2016.htm

The SE05 is a bit big due to a large blank area all around to accommodate the grommets. My initial impression is very high quality construction.

However, yesterday I found this one from Sunkingdom, rated at 6W:

http://www.amazon.com/SUNKINGDOM-Portable-Ultra-thin-Charger-Compatible/dp/B00Q8HAJQ4

...notice how small the blank area is around the panel, and they claim 20% efficient cells.
Looks like a superb panel, but Amazon don't ship it to Australia!!!!

[BarryK]

Ha, ha, look at that Amazon page for the Sunkingdom 6W panel, it has this:

Attention:Don't place device under the sunlight for a long time,even though we have the pocket design.as direct sunlight and over-heat may damage the device.

It will take 5 - 6 hours to charge a smartphone, sitting under the hot Aussie sun, but we can't do that?!!!
...unless they mean the smartphone or other device that is being charged?

[keithy]

Barry the 6W one that looks like this: This one is advertised at around 20% efficiency.

But there is a newer 6.5W version which looks like this: with a built in kick stand. This one is meant to have higher efficiency of around 23.5%. This is the one mentioned over at CPF.

It will take 5 - 6 hours to charge a smartphone, sitting under the hot Aussie sun, but we can't do that?!!!
...unless they mean the smartphone or other device that is being charged?

Yes, I believe they mean don't leave the device (or battery pack) in the back flap where it can probably reach temperatures of over 45C - which could cause the charging controller in the device/battery pack to stop charging.

I was looking into the losses through my various cables as I used to run a USB extension cable from the output of the panel (strapped to my pack) and the device inside my pack so it doesn't get hot. The voltage and current drop from my 1M extension cable was terrible, so I use a better quality 28/24 AWG guage 1m cable now instead.

When testing on hot sunny days at home, I run the cable into a polystyrene "esky" type insulating box where I put the phone or battery pack so it doesn't heat up from the exposure to direct sun.

[Watertank]

According to Amazon when I checked the 6.5 watt does ship to Australia. See http://www.amazon.com/SUNKINGDOM-Univer ... 34&sr=8-27
I've found with Amazon that if I search through similar products I often find a seller that does ship to Australia.

[BarryK]

I reckon that I have got what I need. I cut-down the SE05 (Sunkingdom) 5V 5W semi-flexible panel, using a hacksaw.

It now weighs just 92gm. Puts out just on 0.7A. Measures 165 x 177mm, now fits in the external zip pouch of my waist pack.

So, have reported on this, and basically wound-up the page:

http://barryk.org/light/solar/panels-small-2016.htm

[Eljimberino]

Great stuff- thanks

[BarryK]

I just stumbled upon this one, Suntactics sCharger-5:

http://suntactics.com/shop/scharger-5-portable-usb-solar-charger/

Interesting, as it is specifically designed for direct charging of a smartphone, with some kind of auto-restart technology if the panel is temporarily shaded.

There was one user report though, that stated it stopped working in hot weather. Um, where was that, yes, here:

http://walkingwomad.com/2016/02/10/pct-15-gear-review/

Quoting:

Worked well in full sun buuutttt only if it wasn’t too warm. I could just forget charging my phone (the Iphone charged better somehow, probably because the battery is smaller or so) in the heat of the day. Once the panels were hot they would no longer charge my phone. HQ often strapped the panel to the top of his backpack and charging would function well as long as we didn’t walk through shady spots all the time. Idealy though the panels would lay in the sun somewhere (cloudless sky) where there was also a breeze to prevent them from overheating too fast. We’ll continue using this solar panel on future hiking trips. It’s not perfect, but most of the time it does the job.

[BootBoyer]

As per my knowledge the poor quality of cheap usb cables is no surprise. Try scraping the bare wire and see if it is actually plated aluminium wire. This apparently is a common technique used to make cheaper aluminium wire appear as if it is copper. I had a look at youtube but I can't find the video where someone actually did scrap some wire and discovered it was coated aluminium.

[flywire]

I reckon that I have got what I need. ... So, have reported on this, and basically wound-up the page: http://barryk.org/light/solar/panels-small-2016.htm

Don't be too quick ... the Amazon reviews indicate that the similar panel has a limited life.

[jakeyarwood]

Fantastic info, thanks very much folks.

[Eljimberino]

How is the SE05 Thinfilm 5W 5V panel holding up over time Barry?

[Eljimberino]

Found this solar charger: https://www.kickstarter.com/projects/in ... escription

[keithy]

Found this solar charger: https://www.kickstarter.com/projects/in ... escription

I've been fascinated by OPVs for their thinness, weight and that they can be printed onto plastic. When I looked into it a few years ago however, the commercial modules had very low efficiencies - under 3% from memory.

I'm sure they've improved, but I haven't looked into them for a few years so I don't know what efficiencies they are doing now.

The main issues I'd have with this particular model though are:

• Solar chargers with built in batteries - the built in battery will get extremely hot while the panel setup is left in the hot sun. This might not be as big an issue at higher altitudes where the ambient temperature is very low or close to freezing, but for most conditions, the battery temperature after being left in the summer sun will exceed the operating temperature of the battery. For example most lithium battery packs shut down charging once the internal battery temperature is >45°C. This battery temperature can be easily reached by leaving a battery out in the sun, even without a charge current running through it. They mention in their blurb that the their placement of the battery pack adjacent to the panel is superior than models with the battery pack under the panel - I agree with this, but still think that the battery compartment left in the Aussie sun might well reach temperatures where the battery stops charging.
• the in-built lithium ion battery (appears to be a 2600mAh 18650 cell of unknown manufacturing) is going to be a bit low in charging more than one device. So might be best suited for an emergency use rather than regular use. I wonder if they make it with a replaceable 18650.
• the current cost - the size/weight savings might seem attractive, but this is offset to me at least by the price/power output.

I do like the idea of OPV cells though, and things can only get better and lighter.

[MrsGypsy]

Greetings
I am curious/interested in this topic for myself but I am totally science/maths challenged.

I found this one for sale Amazon US
AUKEY 20W 2-Port Solar Charger with SunPower High Efficiency Solar Panel & AiPower Adaptive Charging Technology for iPhone 6S Plus, Samsung Galaxy S7 Edge and more...
US $53
What do you think?
Is it rubbish?!

[Mark F]

My own research suggests that solar is only effective for long unsupported walks (10+ days) compared to carrying a battery pack of appropriate capacity. It also assumes that you have time to lay out the panel in the middle of the day for a couple of hours or more - hanging it off the pack is not optimal. For solar to work well you really need to use the panels to charge a battery pack and then use the battery pack to charge the device. This is due to the fluctuating power output due to clouds, shadows etc and the finickety nature of apple charging requirements if you are in the apple ecosystem. I noticed this one - very similar and almost the same price - http://www.amazon.com/dp/B012YUJJM8?psc=1 The text on the Amazon is virtually word for word. It appears to be lighter (14.7 oz) and I would trust the Anker brand rather than what appears to be an attempt to piggyback on the Anker brand with AuKEy, almost identical text and image.

[keithy]

Greetings
I am curious/interested in this topic for myself but I am totally science/maths challenged.

I found this one for sale Amazon US
AUKEY 20W 2-Port Solar Charger with SunPower High Efficiency Solar Panel & AiPower Adaptive Charging Technology for iPhone 6S Plus, Samsung Galaxy S7 Edge and more...

AuKey makes some good quality kit. I've looked at their chargers and taken one apart. The panels they use on these are the same SunPower panels used by my Blitzwolf one above, and by the Anker one mentioned by Mark above. With Anker, if you can get them to ship at the same price, they do have a better name and will have a good warranty, including refunding return postage to the US (as long as you buy from an authorised seller).

So far, the portable panels I still have are:

• Goal Zero Nomad 7W 430g
• Instapark Mercury 10W 500g
• Goal Zero Nomad 13w 750g
• Blitzwolf 20W high efficiency panel 550g
• Sunkingdom 6.5W high efficiency panel 250g

The Instapark mercury 10W was my go-to panel for a while, having used it for a few extended trips away from power sources. but against the newer high efficiency panels, it seems to be heavy now and has a lower current output in comparison.

I have tested the newer panels, and in optimum conditions they do output greater current than my older panels, and are significantly lighter in weight as well. Not sure on their build quality or longevity at this stage as I've only had them for a few months.

As Mark has pointed out though, if you are doing shorter trips away from power, there are larger USB battery banks that are relatively reasonably priced that should cover shorter trips. When I used my older panels, I always paired them with two 5000mAh USB batteries, but these days you can pickup 16000mAh USB battery packs for the same price or cheaper than I paid for my old 5000mAh batteries.

Also, where you intend to use it matters. Solar charging worked great for me in a month in Nepal away from power sockets - you could put it on the pack on sunny cloudless days and it would recharge a USB battery pack or camera/phone battery directly. They've worked great for people who cycle tour as well. However, in a heavy rainforest in Borneo, I found it only good at clearings at camps.

[MrsGypsy]

Greetings,

I have found this on amazon:
Portable Charger RAVPower 22000mAh 5.8A Output 3-Port Power Bank (2.4A Input, Triple iSmart 2.0 USB Ports, High-density Li-polymer Battery, Ace Series) For Phones Tablets and More - Black US$40

How good or not is this going to be?

[keithy]

Portable Charger RAVPower 22000mAh 5.8A Output 3-Port Power Bank (2.4A Input, Triple iSmart 2.0 USB Ports, High-density Li-polymer Battery, Ace Series) For Phones Tablets and More - Black US$40

How good or not is this going to be?

MrsGypsy - The RAVPowers are a reputable brand. I have a few of their USB power supplies and one of their smaller battery banks (about 3 years old now). The 22000mAh uses a few flat lithium polymer battery packs instead of cylindrical 18650 lithium batteries, so is reasonably light for the power capacity.

However, you might find that these might not ship from Amazon US directly, and re-shippers are not keen on shipping lithium batteries anymore. If you are heading to the US, then it is a reasonable buy, but as an alternative, check out the newer Xiaomi 20000mAh battery banks.

[kImperator]

Hello together,

lets extend the lists with the ones I have tested

I searched a lot for very lightweght solar panels and have found that there are semi flexible solar cells from the us company sunpower with up to 22%-24%.

So I searched for solarpanels which were using these cells and found the following two panels:

https://www.amazon.com/10-6W-Ultra-Portable-Solar-Charger/dp/B01DZN5Z9E/ref=sr_1_2?ie=UTF8&qid=1486668864&sr=8-2&keywords=kolumb+solarI'm not sure if amazon ships this item to australia, but this product is amazing. 4,79V and 1,29A so nearly 6,2W real outcome at a regular weight of 204 grams


https://de.aliexpress.com/item/5V-Solar-Power-Charging-Panel-Leaflet-A5-Charger-USB-For-Mobile-Phone-Samsung/32690974386.html?ws_ab_test=searchweb0_0,searchweb201602_5_10065_10068_10000074_10000032_119_10000025_10000029_430_10000028_10060_10000067_10062_10056_10055_10000062_10054_10059_10099_10000022_10000013_10103_10102_10000016_10101_10096_10000018_10000019_10000056_10000059_10052_10053_10107_10050_10106_10051_10000053_10000007_10000050_10084_10083_10000047_10080_10082_10081_10110_10111_10112_10113_10114_10115_10000041_10000044_10078_10079_10000038_10073_10000035_10121,searchweb201603_3,afswitch_2,single_sort_2_default&btsid=7c1f38bd-b37c-4d38-aec4-1f611fb98b21
Get the same output as BerryK with SE05 -> 4,7V and 0,7A so arround real 3,3 Watt
I really love this panel, it weights only 84 grams and can be trimmed down a little bit. I have removed a little bit from the top and punched holes on the bottom for fixating this panel on a pack. The reduced weight is 78 grams.


Greetings from Germany,
kImperator

[BarryK]

Today I have tested another little panel. Rated at "10W" with 5V USB regulator. The panel measures just 240x140mm and weighs 86g.

Purchased from here:

https://www.aliexpress.com/item/4000521 ... 0521884418

No, it doesn't give 10 watts! Here is my test:

https://bkhome.org/news/202104/accurate ... panel.html

Note my comment at the end regarding switching regulators and RF radiation.

[BarryK]

Tested another little solar panel, "SLAR" 5W 5V, can be bought with or without the USB regulator. I purchased without, weighs 91g -- a little bit heavier than some earlier ones, and feels more rigid. Dimensions 235x145mm.

Incredible, this vendor is honest. Claimed 5W, I got 3.36W, but under ideal test conditions (1000W/m2 and cell temp 25 degC) it would be higher.

PET coating, which is good.

My test:

https://bkhome.org/news/202105/test-sla ... panel.html

Vendor:

https://www.aliexpress.com/item/1005002251904094.html