What percentage of "solar batteries" expire due to a bad cell?

I suspect the number may be quite high. I also suspect the phenomenon could be greatly reduced by the manufacture of a high quality battery.
Why do I feel this way you may ask. It is because every 8D that is waiting for the scrap yard was perfectly serviceable except for one bad cell, two bad cells in one case. One battery was pushed until it developed two bad cells. FWIW....that particular battery created a 2am power loss in the middle of July in an alpine desert. Bad cells poison the entire array. Two bad cells would seem to destroy the array output. Kind of like a short circuit in a way.
Currently still using three 8Ds that were manufactured in 2011. One is pretty good, the other two are fair to pretty good. Their only other value is scrap lead so I figure they help shoulder the burden for the better 8D batteries. Plus this is an experiment that I like to conduct. My childhood hero was Edison before I learned about Tesla.
Which leads to another subject for conjecture. At what point is it economic to pull a battery? Opinions will vary widely depending on whether one buys or sells batteries I bet.
Why do I feel this way you may ask. It is because every 8D that is waiting for the scrap yard was perfectly serviceable except for one bad cell, two bad cells in one case. One battery was pushed until it developed two bad cells. FWIW....that particular battery created a 2am power loss in the middle of July in an alpine desert. Bad cells poison the entire array. Two bad cells would seem to destroy the array output. Kind of like a short circuit in a way.
Currently still using three 8Ds that were manufactured in 2011. One is pretty good, the other two are fair to pretty good. Their only other value is scrap lead so I figure they help shoulder the burden for the better 8D batteries. Plus this is an experiment that I like to conduct. My childhood hero was Edison before I learned about Tesla.
Which leads to another subject for conjecture. At what point is it economic to pull a battery? Opinions will vary widely depending on whether one buys or sells batteries I bet.
First Bank:16 180 watt Grape Solar with FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
Comments
Oh, yes I have experienced this and have learned a valuable lesson.
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
At 20, I would be prepared to undergo a lot of pretty unpleasant treatment to address a health issue if I was otherwise healthy. At 80, not so much. Similarly, I'd replace a dud cell/battery in an otherwise healthy young bank, but in an older bank I'd be making end-of-life arrangements.
Sulfation is a bit like a slow growing cancer - it'll kill you eventually, assuming something else doesn't get you first, and will make you pretty sick in the meantime. Batteries can also die of something more like a heart attack, when enough plate has shed to the bottom to short the cell. Baby a bank with low voltage absorb etc will likely mean a lingering demise of the first type, vs more aggressive charging regimes resulting in the second.
7 years is getting a bit long of tooth. If I was one of those 8Ds, I'd be getting my affairs in order.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
I still have four 8D's of mediocre quality left over from my last bank using eight 8D's of mediocre quality. Remnants of a "beginners mistake". Thinking I may wait until a bad cell develops before yanking. Unless, of course, SG drops below fair.
Built in 2011....yes. But not placed into service for a few years. Stored in cool to cold conditions. Which reminds me, the bottom battery bank is cooler than the top bank was. The bottom batteries have fared much better. I think ~75% of my replacements went to the top bank. Wish I had kept detailed records of that.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
A couple feet may represent a significant temperature difference when the lower bank is virtually sitting on a cool floor.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter