Foldable Solar Charger, Cloud-Restart Test - AUKEY 20W (pb-p2)

11 posts / 0 new
Last post
netprince
Offline
Last seen: 3 hours 58 min ago
Joined: 06/14/2012 - 13:48
Posts: 645
Location: Virginia
Foldable Solar Charger, Cloud-Restart Test - AUKEY 20W (pb-p2)

I recently purchased too many of these fold-able type solar chargers.  Some of them have many reviews, and some have very few, but almost no reviews discuss how the panel deals with shady interruptions like clouds.

NOTE: This is only a test of one aspect of this charger, not a full review.

Charge Restart Feature

Background

These solar chargers are marketed toward backpackers, campers, and/or emergency situations.  In my opinion it makes sense to charge a battery bank with one of these, and then charge your mobile phone with the battery bank later on (after dark?).  These chargers can also work directly with your mobile phones, but that is a tricky endeavor. 

Many mobile phones (and some battery banks) will not adapt to the changing power provided by a solar charger.  For example, current generation apple devices will start charging at full power, but if a cloud reduces the output temporarily, the apple device will not resume charging at full power. 

In response to this, some solar chargers have begun adding charge-restart features to their circuitry.  The theory is nice, the panel detects an interruption in solar energy, and briefly cuts power to the usb ports.  This should trigger an apple device to automatically resume charging at full power.

Drawbacks

Depending on how the charge-restart feature is implemented, there could be some serious drawbacks.  Ideally the solar charger would reset the usb ports only once, after the cloud has passed.  That means the charger has to notice a sudden increase in sunlight, and reset the device.

Some solar chargers are taking the easy way out, and just cutting the ports off when the output voltage drops below a certain threshold, say 4.4v.  This method means that when a cloud obstructs the sun, power is cycled immediately.  But as soon as your device begins charging, the voltage will drop again, and power will be cycled again.  This will repeat until the obstacle passes.  This method could be very bad for your device.  This method also makes it impossible to trickle-charge your device.

In this test I will try to determine if these solar chargers have a 'charge restart' feature, and if so how well it works.

 

The AUKEY 20W (pb-p2, purchased on amazon, March 13, 2016)

Some Pictures


IMG_20161112_133521.jpg



IMG_20161112_133529.jpg



IMG_20161112_133548.jpg



IMG_20161112_133649.jpg

The Test

In my test, I tried to obscure the sun as much as possible without cutting power to the device being charged.  For this charger, I closed the third panel over the second panel, leaving only the first panel exposed to sunlight.  Then I used a semi-transparent piece of plastic over the last panel to further reduce the output.  I monitored the charge rate with a simple USB charging meter.

After the charge rate slowed to almost nothing, I removed the plastic and opened the panels back up.  Here are the results:

From what I can tell, the Aukey 20w (pb-p2) does not have charge restart technology.

NOTE: This is not necessarily bad, see the 'Drawbacks' section above.

 

The Specifics

Resting Voltage
3 panels exposed
Charging Tesa PB
3 panels exposed

Charging Tesa PB

1 panel exposed

Charging Tesa PB
1 Panel with Plastic Cloud

5.26v 4.86v/1.55a 4.4v/0.69a 4.11v/0.06a

 

 Additionally for this panel, I tested an iPhone 6 with an obstruction.  I closed the third panel over the second, and covered the first panel with my plastic cloud.  The iphone charge rate dropped to 0.08a.  After I removed the plastic cloud and exposed all panels, the iphone still only charged at 0.08a.  This is what the charge-restart feature is supposed to help with.  I will be testing more fold-able panels in the future...

 

Conclusion

In my opinion, the AUKEY 20W will work great for charging a power bank or android phone, so long as the PB or Phone dont stop charging after temporary reductions in power.  It would also be great for trickle charging devices in not-so sunny conditions.

The AUKEY 20W will have trouble charging an IOS device on a partly to mostly cloudy day.

I always recommend you fully test your setup in varying conditions before you rely on it.

 

EDIT: typos
EDIT: add a conclusion

Edited by: netprince on 02/15/2019 - 12:44
will34
will34's picture
Offline
Last seen: 10 hours 23 min ago
Joined: 12/18/2012 - 00:12
Posts: 4090

Thanks for the review! after the clouding, did you wait some time for it to restart? The restart function is not smart in these panels, they are activated with a timer after a voltage drop is detected, some take 2 minutes others up to 5.

I bought two “20W” panels, neither have the restart function and one of them had the so called “Smart output” but turns out to be a fraud, everything is coded equal…not wasting any more money on these until a more reliable tech comes out.

netprince
Offline
Last seen: 3 hours 58 min ago
Joined: 06/14/2012 - 13:48
Posts: 645
Location: Virginia

Thanks will34…. I did not wait very long after removing the simulated cloud for the panel to restart the ports. I am curious now, will have to try it and update the test.

If you dont mind me asking, which panels did you get? I know they make a few custom charge cables which will force the charge coding, perhaps that might help in your setup?

will34
will34's picture
Offline
Last seen: 10 hours 23 min ago
Joined: 12/18/2012 - 00:12
Posts: 4090

I got a $35 generic no-brand panel from AE and another one from amazon supossedly higher end: https://www.amazon.com/X-DRAGON-Efficency-Technology-Smartphones-Foldable/dp/B00NGKPX4Y

They have the same performance and never got more than 10W from either. The one from AE has very unstable voltage and will continue to supply power even when it is below 4.5V. The Xdragon panel has better stability but everything is coded DCP and it won’t handle a true 2A load either.

netprince
Offline
Last seen: 3 hours 58 min ago
Joined: 06/14/2012 - 13:48
Posts: 645
Location: Virginia

I’ve seen that xdragon panel, got close to getting one for testing. They are made by allpowers right? I did get an allpowers charger, hoping to review it soon.

It seems all of these ~20 ish watt panels are really around 10w total. I was hoping to find one I can draw 2A from, but I haven’t seen those conditions yet.

Have you seen these special cables? The coding is in the cable… I have one for my lower-end panels, it seems to work.

https://www.amazon.com/gp/product/B0088HTYUE/

will34
will34's picture
Offline
Last seen: 10 hours 23 min ago
Joined: 12/18/2012 - 00:12
Posts: 4090

These cables are just same as regular USB cables, just without the data lines and with heavier gauge power wire. They only have two leads: -ve and +ve, do not add or support any kind of charge coding including quick charge, it actually just removes it so the device doesn’t detect it as USB. Any high quality USB cable with at least 24AWG power wire should charge at maximum speed without noticeable voltage drop.

netprince
Offline
Last seen: 3 hours 58 min ago
Joined: 06/14/2012 - 13:48
Posts: 645
Location: Virginia

The data lines in the cable I linked are shorted, so yeah not very smart. But standard USB power is 500ma, and the cable gets me up to 1A.

But I dont currently have any devices which I can count on to draw 2A, that would be the ultimate goal. Nothing like drawing only 5W from a ‘claimed’ 20W or 21W panel right?

Jinx
Jinx's picture
Offline
Last seen: 2 months 2 weeks ago
Joined: 10/16/2011 - 11:35
Posts: 1130
Location: Just outside the EU :)

The ravpower version that looks very similar is also the same, I tried with my li-ion charger and the power reduction is a real PITA. It must be very hard to optimise a restart feature as sun expose is so completely random.

I did a rambling video of the ravpower on YouTube, its not a very useful vid but if you are interested it’s up there.

netprince
Offline
Last seen: 3 hours 58 min ago
Joined: 06/14/2012 - 13:48
Posts: 645
Location: Virginia

Jeansy, sorry I missed your post, yes I am interested in the video

Jinx
Jinx's picture
Offline
Last seen: 2 months 2 weeks ago
Joined: 10/16/2011 - 11:35
Posts: 1130
Location: Just outside the EU :)
netprince wrote:
Jeansy, sorry I missed your post, yes I am interested in the video

Ok Netprince, I will hopefully embed it here if I can get it to work…

If not, link here: https://youtu.be/_QWfCJ7Wbr8

netprince
Offline
Last seen: 3 hours 58 min ago
Joined: 06/14/2012 - 13:48
Posts: 645
Location: Virginia

Thanks, nice review, I am going to have to find one of those newer ravpower units, would like the bigger one if I can find it…