Mini project by Kiriakos: Solar powered Agilent U1272A & U1273A

[Kiriakos GR]

It looks that God loves me up to a point. 

I got today just two hours of acceptable quality sun light for my experiment.
The quick summary is that 100 minutes of sun light was capable to bring the batteries charge from the 40% up to 90%.
And I am talking about the combined productive curves of both logging sessions.

Another interesting factor is the mV loss due the diode which is 300mV.

Last but also interesting is the drop which caused by 99% by the batteries, when the voltage started to raise more than 5.3V  (Green line).

I do feel so happy, that today I will install my second panel at the U1272A too.
If this is the gain even under partially cloudy sky, then this setup it can perform and even better, and so I can trust it.
I am ready to scream ....  Success !! 
 
 

[Kiriakos GR]

Today I was having almost perfect sunlight conditions even for a beginning of winter.
It is known that among other things Greece haves lots of sun light in comparison with any European country.
Here are my thoughts divided in titles.

a) The solar panel.
I got lucky with it about physical dimensions VS output in Watt.
At 5V it did see a peak at 67mA, but the average Max output is 60-62mA.
The peak voltage with a diode connected is at 5.8V, which is good enough as target voltage for charging those Nimh.

b) Nimh charge.
By having the solar panel as charger which is 90% capable for what a perfect charge requires, I had the chance to actually study the way which the batteries behave when they are getting charged, and even to record with data logging all their behavior.
As soon the voltage got up to 5.36V the panel was able to give 20mA which was not enough to top up the batteries even further.
By powering up the multimeter (U1273A) the battery indicator shown 100% of charge.
By testing one battery of the four with my professional battery tester (with load), it shown 90% of charge at 1.30V.
Generally speaking those results looks great, this multimeter will never run out of power no matter the percentage of the top up charge limit.

c) The U1273A / Power on / consumption.
By having the Fluke 28II to monitor the charging current, it was easy as toy to measure and the consumption of the meter.
By removing the batteries and just with the solar panel the meter boot up and feels very happy, even the battery indicator stays at 100% just by the sun even at the maximum OLED brightness level.
OLED Max = 32mA
OLED Normal = 30mA
OLED Low = 22mA
This panel is double in Watts than what the meter needs as power, and so the booting up and operation just by the power of sun is 100% guaranteed.

d) The results with the U1273A which requires a bit more mA that the U1272A are so acceptable that with out second thoughts I did the installation of the second solar panel at the U1272A too.
Today both meters are loaded with solar panels and both look great too.
The truth is that I got also lucky about the placement of the panel at the back, the meter haves rubber feet which keep the panel away from touching the bench or at any surface under the meter, in other words it is safe and well protected.

e) The total cost of the needed materials is no more than 10EUR about two solar panels and diodes.
The latest Sanyo Eneloop 1800 series are not expensive either, and they are the best rechargeable batteries for multimeters due their low self recharge characteristics, I could even say that they are even better than what is needed today by the people which regularly user their meters, and the self discharge never was an issue to them.
As last I have to say that my idea about the placement of the panel and the wiring,
It does not affect the meter safety in any way, and even the batteries they can be removed and charged with a fast charger too.


Success …  Success …  Success …   

[Kiriakos GR]

One happy moment to remember, Agilent (Europe) liked my project too !!

[Astroplio]

This modification turned out really good, I like very much the end result.

I am interested to learn more details on the solar panels you have used. Are you satisfied with the overall quality of the panel? Is it sturdy enough? Well, I see that it has a PCB backing, so it should resist twisting and bending, but I am wondering if you ever felt you could brake it when handling it. How about scratches or dirt? Is it scratch resistant or you need to be careful not to place the multimeter with it's back down on an uneven surface? Dirt/dust washes off easily or leaves traces behind? (well, maybe too soon to tell...)
Can you share the link from the buyer you ordered it from?

Thanks, George

[Kiriakos GR]

Dear George.

Yes electrically my combination of materials it does work well.

The mechanical straight of this setup it is related with the working environment that the meter lives in, plus other factors like how its person handles their tools.

Personally I use always soft bag or hard cases to protect my measurement instruments.
The safe transportation of them from site to site is an important factor to me.

Those solar panels are inexpensive and easy to replace, but I will install one screen protector (PDA screen) as extra shield.

About a source for buying those panels there is plenty, the dimensions will lead any one to get an identical solar cell.
I do not whish to make publically known the ebay seller that I got those panels.
He was had them listed as more powerful in a way about the volts output, when most others was more honest on that.
I did shown trust that I am getting something better than the average ones, and I got mislead in the end.
My own measurements are in a way some hard evidence about the true output of the specific solar cell product.

About me as soon I will have some spare cash I am going to buy a second soft case for the U1273A, and actually the Agilent one, which is extremely well designed for it. 

[Astroplio]

About a source for buying those panels there is plenty, the dimensions will lead any one to get an identical solar cell.
I do not whish to make publically known the ebay seller that I got those panels.
He was had them listed as more powerful in a way about the volts output, when most others was more honest on that.
I did shown trust that I am getting something better than the average ones, and I got mislead in the end.
My own measurements are in a way some hard evidence about the true output of the specific solar cell product.

About me as soon I will have some spare cash I am going to buy a second soft case for the U1273A, and actually the Agilent one, which is extremely well designed for it.

OK, I understand. Yes, I can see what you mean, I share your passion for clean, organized instruments, ready for use when needed. (I have noticed you do the same for your hand tools.)

And you know what, I just realized by seeing the photo above how neat is the design of that meter.
I haven't noticed before that it had sockets for the leads to snap-on behind the meter, so to keep them nice and tidy!

When reading reviews of DMMs I mostly focus on the specs and the display, and I usually consider secondary the usability and overall design of the meter. From now on my eye will be more observant on these matters.

I have to go back and check more carefully some reviews; myself I am trying to save money to get a nice new modern multimeter, but I also need a power supply and a function generator, so we will see what I will get first...