TRONIC Eco 4000 Baby C NiMH -- Mini Review -- After 12 Months Shelf life

[Kiriakos GR]

Originally I was aiming to get several 9V Block NiMH from the latest Lidl offer in my area, and I did got the last four packages, but there was also one last package of Baby C NiMH and I did grab this too.
My analog BBC Metrawatt MA4S this using combination of one 9V Block among with one Baby C and I though that NiMH cells will be a great choice for it in long term.

While Panasonic Eneloop this is my first choice, this does not produce 9V Block, and I thought to give a chance to TRONIC battery series.
First detail which I did notice at TRONIC Eco 4000 which I found by them having a complete year of self life, this is that remaining capacity this was no higher than 50% while 75% this is the claim of TRONIC.
 
TRONIC Eco 4000 cell after unboxing:
No1 cell: Came with  50% capacity | 1.24V | Internal resistance 18mOhm
No2 cell: Came with  50% capacity | 1.24V | Internal resistance 16mOhm 

After the first charge cycle and six hours off charger I got new measurements.
No1 cell: Came with  100% capacity | 1.36V | Internal resistance 18mOhm
No2 cell: Came with  100% capacity | 1.35V | Internal resistance 20mOhm 

For a better evaluation I will use my modified PowerLine 4 Pro with external and adjustable battery cell holders, so to benchmark TRONIC Eco 4000 performance after running Charge/Refresh special program, which this automatically charge/discharge the cell as many times it is needed until the moment which the cell will deliver repeatedly identical mAh output. 

For now I will add few product pictures, and later on I will add data from my first evaluation.   

[Kiriakos GR]

By this opportunity I will demonstrate few pictures of my own and modified Ansmann ( Charger Test system).
This is 100%  Kiriakos inspiration and design. 

Regarding specific test statistics, because charger works at maximum and deliver 800mA charging current and 400mA discharging current, several cycles will require two to three days of time.

 

[Kiriakos GR]

Final results of delivered capacity after roughly 10 charge / discharge automated testing process.

Cell No1 with less internal resistance this can storage 3820 mAh
Cell No2 with a bit higher internal resistance this can storage 3730 mAh
 
Generally speaking at both cells there is lesser storage capacity than the expected.
From best cell there is missing 4.6% of storage capacity and 7.2% from the other.

My very own lesson from several NiMH cells then be at highest capacity of AA type, this is that their shelf-life this is much smaller (using them or not) due active chemistry this deteriorating internal battery parts, two and a half years of life this is the most that you can get when using them at camera flash light.
For Tronic C 4000 if you use them with RC car they will have the same fate, but as power source for an analogue multimeter Ohms range, this is not called abuse. 

[Kiriakos GR]

New product testing opportunity started, this time about TRONIC Professional  4000 Baby C NiMH (Blister with Red markings).

Supposedly this is different class compared to ECO line, and they are because both cells in my package arrived at 0% remaining energy to use  = 1V DC voltage.
Interestingly enough, after five charge / discharge cycles, neither these has measured capacity larger than 3750 mAh.

Internal resistance measured at 10 milliohm in both, ECO line was having double than that,  High quality Panasonic equivalent type cell note at datasheet 5~8 milliohm internal resistance.
   
My problem with these cells this is poor specifications documentation.
I had to research similar products so to discover truths which consumers they must be aware.
For example these 1000 named charge/discharge cycles, this is valid specification when batteries are not abused by electric load higher than 1.8A nor be charged with fast charger.
Such battery cells power a portable small size vacuum cleaner ( 4~6A load) they will have only 500 charge/discharge cycles.

First test which I tried to run this is High- Current discharge by electronic load, 3.6A was possible and at 4A the test failed.
Supposedly this type of cells it can handle even 5A and 10A as fast discharge.

Theoretically all consumers they should gain electrical specifications understanding not only from text but also from symbols printed over the packaging.
But only an electrician he is aware of actual consumption of medium sized FM Radio, Remote control toy or of a torch light.
Combined information this now translates to:  Baby C NiMH for moderated and or Low drain applications.  in which 3.5A this is highest limit.

In conclusion only thing that now I am up to discover, this is actual discharge current which I will also succeed getting at least 3500mAh capacity from them.
By getting this information at hand, then I would be capable to decide precise range of applications that I can use them with out destructive consequences for them. 

For now I am presenting blister package in which I add numbers next to applications icons, for your better understanding. (save the picture in your PC for higher readability)
Product testing takes time, results will be posted in a few days.

[Kiriakos GR]

First test completed successfully 

Both ECO and Professional series delivered at 1C discharge rate (3.5A), quantity of 2665 mAh within 45 minutes.
Test conducted at room temperature of 14Celsius.
Battery temperature variation under load.
10Min = 22C
20Min = 24~25C
30Min = 26C
40Min = 28C
45Min = 28C

Combined voltage at no load = 5,732V
After DC load activation, output voltage sag at 4,917
Voltage per cell at such load at about 1,1V 
Test Cut of voltage 3.9V     


Voltage curves comparison this is very interesting, while voltages of its pair were very close to its other, as some point Professional series which was a little behind, this raise up it performance at about 35 minutes under test, at that point battery temperature was at 26C, and new conclusion made this is that their performance this is temperature depended.

ECO series this delivered a much more expected discharge curve, and did not shown having such temperature depended performance.
For everything there is an explanation, this experiment confirms that ECO series it has rather less active internal chemical agent, this will help it self-life.

Second myth-busting conclusion this is 4000 mAh named capacity, both series perform identically at 1C discharge rate according to 3500 mAh named capacity from other manufacturers.
At this 1C test, test results matching performance of GP350CHC their datasheet it is available on the net.   

I am going to also run two more tests, first one at 0.5C = 1750mA  and the second is 0.2C = 700mA discharge rate.
Both tests will not activate temperature depended behavior of Professional series because previously test shown that at 0.6C rate, the cells did not get warm above 22 Celsius (1.8A test) which my logging ended prematurely because one of three blue-tooth modules this run out of battery power.