Mini project by Kiriakos: Solar powered Agilent U1272A & U1273A

[Phyllomedusa]

Jepp, solar panels vary pretty much in output depending on the brightness. I saw the same behaviour with some 50W Panels I was working on.
On a sunny day or setup was enough to keep a small netbook running and collect data, but just a few clouds and the output dropped considerably. So we skipped the netbook option and stayed with our small datalogger as that one just needed a few mA's to run properly.

and believe me......if you really need the data from long time logging you wouldn't play around with some testdrives (will it work or not) and cross your fingers to get them .
I am thinking about, maybe, a solution with a Lipo from the RC shop to run my meters for really long logging periods. They come quite cheap  and go up up to 5500mAh. That would improve the runtime a lot I guess (compared to the 300mAh or 800mAh from normal rechargables)

[Kiriakos GR]

The subject about extended time data logging and data loggers, worth's having its own topic. 

While those Agilent meters they can greatly assist as data loggers, 
for extremely long duration of data logging, I do consider as waste of resources about keeping as slave for this job one so talented meter. 
 
Unfortunately the pricing about dedicate data loggers it does flying high in some situations.
Either way for my needs about data logging the U1270 series is all that I need, and the solar panel addition will give them the ultimate perfectness    I am almost 98% positive that my idea will work out. 

What I am looking to find right now is flat tape cable that I can use solder on it.
I have one piece from a CD player that I have take apart, which it does the job about passing from the battery cover with out stressing anything.
But I am also ready for a plan B,  that is a copper foil and heartstrings tubes. 

[Phyllomedusa]

I totally agree that for long term logging a dedicated datalogger is the better choice. Well, sometimes I just need to watch the sensor output or battery voltage of a system for some days and here a logging Multimeter is veeeery handy.
I already have it, it doesn't need a separate battery or drain the system battery as most dataloggers do, it is compact and robust.
For example:
We had installed some climatological stations in the tree canopy in central french guyana. These systems had a solar power supply (5W Panels) which recharged the battery for the logger and its attached sensors. As we wouldn't stay there for three years, I had to climb up there, install them and check that they could run without regular maintenance. So I needed to watch the battery voltage over a period to see if it drops rapidly and the stations would be out of order or if it would be stable (at least for some month to bring in a freshly recharged battery).
At that point I didn't have a logging multimeter and so I used one of the loggers channels to measure the battery voltage. As our loggers were running on an 60s interval this was ok. But then someone suggested to lower the interval to 30s. So we needed to measure again and loose one channel of the logger.
So that meant....climbing up there in the canopy....playing around with these little Compact Flash cards and hope to to loose on when changing.....go down.....check the data.....and wait for the next change to compare the data.

Honestly...I would have loved to plugin my meter, let it log for about five to six days and watch the tendency without the risk of loosing the data.

Today i quite often use it to monitor a freshly calibrated sensor and compare it to what the USB-Aquisition box reads out. Or is use it to have a finer logging-interval when we work there at night.

Well, I would never have the idea to use it as logger on our stations as real logger as it really is wasted resources then. We measure voltage (rH&T Sensors, Radiation Sensors), Resistance (rH&T...psychrometer, Leaf Wetness grids, Soil humidity), Pulses (rain, wind) and so we never need a diode check or so then.
We use some campbell CR1000x for that and I really love those fellows. Reliable, low battery consumption, packed with features and a lot of possible attachments. If you really want long time logging (months or years)....these fellows are the way to go

[Kiriakos GR]

About my solar mini project...
My pack of 20 x Schottky IN5819 arrived today, and soon this project will start moving again.

The diodes have the KED marking as brand.
In a quick test with the U1273A at the diode mode (Auto mode) the meter reported those diodes as Bad.
It took me some time to realize, that the meter is programed to identify common diodes which have specific resistance and properties.

An simple measurement at the Ohms mode shown by compering a standard diode against a Schottky, an significant difference. 
Schottky IN5819 = 9.4 K Ohm
Common IN5401 = 2.4 M Ohm

While at the common diode range the measurement shown.
Schottky IN5819 = 0.198 V
Common IN5401 = 0.534 V

It looks like that Agilent needs to add on the U1270 series and a special range of Pass-Fail for the Schottky diodes. 

For the time I am a bit busy about the mini review of the Agilent process calibrator,
but I will post updates about the solar project soon. 
 

[Kiriakos GR]

Here is my very basic How-to. 


Materials:
1) Flex  ribbon 2 x 10Cm long ( salvaged from a dead scanner)  with three wires its one stripe.
2) Just a bit of Sekisui 5760 Thermal Tape (dual side) so the stripes which attaching the panel to be locked in place.
3) Professional grade double side tape (automotive - rubber to metal) yes it is very expensive.   

Now have a look at the pictures.
The inner placement of the diode and the flex strips was very easy.
About soldering directly on the three lines of its flex strip was easy too, just needs to be fast at soldering.

One quick measurement at the batteries at 50% charge shown 4.8V
And also 1.5V after the diode (Indoor lights).

The meter is ready to face the sun,  the only problem is that currently the weather is rainy.
I will do one last follow up about the gain of this setup, and a bit of self data logging, will be involved too.   
 

[Phyllomedusa]

Nice! I am curious how it will work. Maybe route the wires out and use the logging mode of the U1272A to log the batteryvoltage over time ....
Then you could check how the system drops down at night and how fast it recovers.

[Kiriakos GR]

I did try to make it to take one self measurement of it is own batteries and I got OL at 1000V.   
With just the positive lead on, it measured 3.2V that is a fake reading.

I think that even the U1270 series works in a similar way with the digital panel meters which need one dedicated power source too.   (isolation from the input terminals)

Now I am using the Fluke 28II to measure the voltage, but the next step is to use the U1272A so to data log the U1273A charging cycle. 

[Phyllomedusa]

Ah yeah, you're absolutely right. I didn't think of the galvanic isolation.

Well, as you're in Greece....maybe you'll eventually get infected with the Photovoltaic virus and do some playing .

[Kiriakos GR]

My next steps will be three basic measurements.

a) Charging current with indirect sun light.
b) Charging current with direct sun light.
c) Gain of both methods in 30 minutes time.

If you have any good idea of how to convert my Honda 250CC semi-enduro to solar powered, let me know. 
One litre of gasoline is at 1.80EUR (regular)

[Phyllomedusa]

uuuui 1,80 is tough. I don't know how much regular is listed here at the moment but I guess about 1,65. We just filled our truck yesterday at 1,49 (Diesel).

Converting your bike....Hmmm, the motor shouldn't be that much a problem....but the batteries . It's always been a challenge
In fact some people did it.....but not solar yet. Well, you could try the Tesla-Idea.
http://finance.yahoo.com/news/tesla-motors-launches-revolutionary-supercharger-032000226.html

at least one company is working on the energy supply problem....and I find it rather interesting that it's an US company (as the USA is always told to be oil-ruled and polluting). Let's hope they can keep that system up and won't cut it down one day due to costs.

[Kiriakos GR]

As soon I will manage to get one good oscilloscope for the ITTSB, the next plan will be to add electrical assistance on my common bicycle,  it would cost around 200EUR, but it is more easy to do.   

[Kiriakos GR]

Who will believe that since the day that I did the final mounting of the panel, I have all those days rain and heavy cloudy weather !! 

Even so today with only 70% sun quality due one period which the clouds was have one opening, and the atmosphere was a bit blurred, I did my first attempt to data log the gain.

The graph shows clearly one raising curve ( Almost good sun) and after about 40 minutes the sun was blocked from dark clouds.

The U1272A was logging the volts, and the Fluke 28II was monitoring  the mA after the diode.
I am optimistic that this setup it can perform ever better.
Today I got one gain of 150mV for 30 minutes, hourly is the double.

I will repeat my tests and I will gather more facts.
On the positive news is that this panel it keeps the multimeter alive just by it self. 

5,36 is the voltage of the four fully charged Nimh (by the charger).