New statistics: 7 years, 9 months, 28 daysVoltage ....Charge Percentage .... Internal resistance in mOhm at 1kHz
No1) 9.56V ... 100% ... 1758
No2) 9.63V ... 100% ... 1130
No3) Dead
No4) 9.54V ... 100% ... 2200
No3) Dead This cell shown issues in the first year, suddenly this were overheat at the bottom corner, it took me several weeks to understand that one cell did shorted.
The case was slightly deformed, no flames, no holes.
This 9V Block still was receiving a charge and appeared functional for small loads, three years later .... it stopped working.
I am not the only one faced such an incident.
As I found a photograph (from Amazon Review) and from older revision of TRONIC Eco 9V, this one truly burst, deformed plastic case and even opened holes.
At electronics production we do forgive a fail rate of 3%, but in this case a television for example will come DOA, or will fail in the first week.
Rechargeable batteries from the other hand, they need
weeks or months, to prove them self's as healthy.
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After 7 years, 9 months, 28 days

I have the curiosity to discover how many mAh they hold the alive ones.
I did a quick test at 200mA discharge , 7 V Cut-Off. No1) 176 mAh
No2) 156 mAh
No4) 151 mAh
No I am looking for a way to do a proper test with
50mA discharging current.
Which this is considered as
scientifically correct for a proper capacity measurement.

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The supplier whom sold these cells to Lidl, was a German company that this is now dead.
I did a research, so to find out
if my Ansmann chargers (Energy 8 and Energy 16) they could kill a battery with their charging current of
70mA 
but
this is impossible.
TRONIC released few chargers of their own, the production
2017-2018 this was able to deliver 30mA as charging current = Slow automatic charger.