Mini project by Kiriakos: Solar powered Agilent U1272A & U1273A

[Kiriakos GR]

Well those Agilent U1272A & U1273A with the newly shown Eneloop 1500 series AAA, they did become very close friends.

And I am happy all ready but I decided to try one experiment which if it work it would be an amazing solution.

The idea is to add on the holster one solar panel which will act as permanent trickle charger when the meter is just seating out of use in my workshop.
By this way I hope to fight back even the self discharge rate of those NiMH. 


Originally what made me think this idea was one tiny solar panel from a flash light, which it found to be very weak to perform this task.

Before few hours I was looking on eBay and I found those theoretically ideal panels with specifications.
6.8V
90mA
Size : 90 mm x 35 mm

The holster it self is 50mm at the narrowest point and there is 92mm available space vertically.
What I hope to succeed is getting 5.5 volts from this panel even with indirect day light.

I will find the truth in few weeks, as soon those panels arrive.
If the results are satisfactory, I will mount them on the holster with dual side tape (professional quality made in UK).

The price of those two panels was 7.86EUR shipped.

By the use of Adobe Photoshop I made one image so to give you the idea of how it will look like. 

The panels are covered with protective clear material and so they are protected.

The connection with the batteries will become with flat cable tape, and so I hope that the all idea, it could work out with out any modifications at all.

Another great thing with the holster of the U1270 Series is that under the meter there is rubber points which keeps the meter in to a specific level and the holster haves a clearance of 10mm from touching the bench.

So far everything looks ideal. 

[Kiriakos GR]

Destination - Greece
The item (RC186281802HK) was posted on 17-Aug-2012 and is being processed for delivery to the addressee.

http://app3.hongkongpost.com/CGI/mt/enquiry.jsp

It looks like that my eBay seller is a gem about speed. 

[mjlorton]

Greeting Kiriakos!

Great to be in "your home" for a change!

As you can imagine....I really look forward to your solar powered Agilent multimeter project. I love the simple approach and design.

I have quite a few projects around the house with little solar cells similar to the one you have on order and they are a wonderful solution for smaller DC powered projects.

One small step into solar power....has led to another....let it continue good man!

Cheers,
Martin.

[Kiriakos GR]

Greeting Martin!

I like to thank you for your gentle push about getting involved with small solar projects.

Due the fact that this is my first true attempt, I do feel a bit like my homeboy Icarus.

http://en.wikipedia.org/wiki/Icarus

But I will watch out the sun to not melt my wings too.   

[mjlorton]

I think you will fly high!

I'm using my U1272A at the moment to monitor a little solar project and battery life is becoming an issue (still far better than the Fluke 287!). When time allows I might consider doing the same as well....although I need to get my Fluke 287 into a "happy state" first! 

Cheers,
Martin.

[Kiriakos GR]

My panels arrived today from China, that is 11 days a new world record. 

The panels looks good and even about the dimensions part, I did 100% the correct choice.
On the top of the active surface there is a protective soft nylon (clear)  that must be removed, but I will not remove it yet, and so accept my apologies about the blurred full of bubbles look of those panels.

I had very few time to play with them today.
In a very quick test, I manage to get the 6.4V with out load.
And 3.5V at 62mA of load, that I did not liked that much as first impression.

Later on I will do a more precise testing on them.
For the time enjoy the pictures .     

[Kiriakos GR]

Gentlemen !! 

The precise testing payed out.

I have a bag of 50 white bright LED and resistors which I got for a project that I never started.
Its LED plus resistor at 5.000V it needs 6.0mA ( confirmed that with many single LED + resistor pairs).

The next step was to use this load so to see how the panel respond to it.

And so I made one list of measurements that shows the truth about this panel.
And I ended up with those results of mA of load VS DC volts panel output.
28mA = 6.0V
47mA = 5.6V
56mA = 5.43V
65mA = 4.96V

Those numbers look very promising that my idea it will work / succeed.
I very happy with those results mostly because I am not in danger to become a laughing stock. 

Because I am a bit busy those days this project in not top priority.
But as soon I will have more info about it I will post it here.

What matters to me the most, is to find all the small details so to make this to work with out any need about modifying the multimeter in any way, not even a small drill hole on it.
All those details require lots of thought and the right materials.

For now have a look at my interesting pictures, and have a good laugh about my solar transformer LOL   

[Kiriakos GR]

The next thing that you learn as soon you start playing with panels is the Schottky diodes.
The most famous one looks to be the IN5819 and so I did order some of those too.

Who knows?  if I do  enjoy the results of this project, I could possibly move in to something bigger later on, like a portable solar charger. 

[ElectroElvis]

Hello Kiriakos,

after a long time a post again, I had some troubles, I moved and I got new job, so now I can again dedicate my time to electronics.

Today I bought similar solar panel (polycristaline) from Conrad and I paid 13€. As for specs go it says: 6V at 150mA which should be ideal for powering things and recharging some batteries. When I get some sun I will test it and provide results under load.

Elvis

[Kiriakos GR]

Hello Elvis,
It is nice to having you back. 

Oh my, Conrad ripped you ? 
at list you got it with out waiting 2 weeks.

I am waiting for the diodes to arrive so to continue my project.

Luckily I got locally as gift one DC/DC mobile phone charger, the one that takes 2X1.5V AA and gives an output of 5V.
If for any reason I change my mind, I could try my panels in parallel and make a charger.
 
I have also some ideas about a simple project as load tester for such panels.
But I will not say more for the time. 
About your panel start a new topic by having as title (for example) : Solar panel 10x14 200mA 5V review.
And add you findings there, I would love read your news about it.

[ElectroElvis]

Thanks for advice,

I definetly will do a topic like you said, once when I do the measurements and take some photos.

About ripping me off, I have no clue, I am just in dilema if it will costs me less to buy those little things from ebay or from local dealer like Conrad.

I still need to get multimeter, and sadly I also become "scopeless" since I had to sell it due to moving issues and bills. Hope in future I can get another one, maybe some cheap DSO.

Elvis.

[Kiriakos GR]

Today is 14 of September, and finally some blessed rain fall in my city, the summer was totally dry in my location. 
The sky is covered with white bright clouds and the sun is fully covered.

I am still waiting for my large pack of diodes to arrive, and so I just thought to test those small panels under a cloudy weather.
My measurements shown that the solar panel is totally incapable with cloudy weather to produce any usable energy.
My measurements shown that the panel with out even any load, it was NOT capable to give more than 4.5V when in a good day it was producing 6.4V

I also made one second measurement with just one LED as load .
And I got 3V at 0.60mA  that is just half milliampere.
 
By observing those numbers in comparison with the ones that I got under bright Sunshine as  65mA at 4.96V,
what comes in mind as conclusion is that  those solar panels its like Go or No-Go operation.
Which brings to mind the picture of a very narrow logarithmic scale.

Probably I sound like a kid who discovers the world, but it is almost that way about solar panels.
Marketing agents of solar energy products are trying to convince the new customers that one solar panel installation is capable to offer linear output even at cloudy days,  my measurements at this small scale test, proves that this is a fake advertising.

Thankfully Greece haves about 95% per year sunny bright days, which helps the solar energy production tremendously.         

Even so I do love those measurements and comparisons, as we say = Food for thoughts.