Dead cell frustration

[Graycruiser]

After replacing two sets of batteries because of overcharging abuse I finally learned. I paralleled two 4D batteries and used an ACR to charge a starting battery, installed a battery monitor, shore charger with temp sensor, and hi-output alternator with temp sense on the alt and house bank. I monitored the SOC carefully, never discharged below 50% (ave 25%), monitored the water level. in short, I babied these suckers. Now, 4 years later, frustration.
This past fall, before closing for Winter I was testing to see if equalization was needed with a temp compensating hygrometer. All cells were in the green and within tolerance, except one. This cell on the end away from the posts, was flat: not short, not open, just flat. Zero, zilch, just plain water. The voltage on this battery was 10.5.
What could cause such a condition? Could I have failed somewhere along the line? Are batteries just prone to this type of failure? Is there any way to recover from a dead cell?

 

[Benny17441]

It has been my experience over many years dealing with wet cell batteries that some can be mistreated and seem to refuse to die while others can be cared for and still suffer a premature death. I do not think the manufacturers can substantiate with any degree of certainty how long one of their batteries will last. This uncertainty is what gave rise to the "battery warranty" industry. Some of the lesser marine battery manufacturers are doing away with providing any warranties to compete on price alone.

 

[shemandr]

I'm not knowledgable about batteries but when my car battery died after 10 months, the dealer shrugged his shoulders and said something like "They're born together at the factory. Some go on to live long lives and some die young."
I was thinking they should check the regulator, which thru Maine's postings I've learned are "Dumb." Maybe I'm frying the batteries. Dealer was not interested. The battery was replaced, I got shown the door and a pat on the fanny, and our lives go on.

 

[Maine Sail]

After replacing two sets of batteries because of overcharging abuse I finally learned. I paralleled two 4D batteries and used an ACR to charge a starting battery, installed a battery monitor, shore charger with temp sensor, and hi-output alternator with temp sense on the alt and house bank. I monitored the SOC carefully, never discharged below 50% (ave 25%), monitored the water level. in short, I babied these suckers. Now, 4 years later, frustration.
This past fall, before closing for Winter I was testing to see if equalization was needed with a temp compensating hygrometer. All cells were in the green and within tolerance, except one. This cell on the end away from the posts, was flat: not short, not open, just flat. Zero, zilch, just plain water. The voltage on this battery was 10.5.
What could cause such a condition? Could I have failed somewhere along the line? Are batteries just prone to this type of failure? Is there any way to recover from a dead cell?

Unfortunately this falls under $hit happens. Sadly most all 4D & 8D flooded batteries are not true deep cycle batteries even though they are marketed as such.. I have even seen 4D & 8D starting batteries labeled as "deep cycle"... It is probably not a failure of yours but rather a failure of the wrong product for the application...

 

[Benny17441]

The question now arises; is our time and effort in maintenance and investment in the more sophisticated charging and monitoring equipment worth it? My answer would be yes, not for the sake of batteries longevity as that seems to be a crap shoot, but for my maintaining a reliable power source away from the grid. Our safety is sometimes dependent on radio or navigation electronics and on being able to start the engine so whatever we can do to insure we have redundancy and adequate power capacity when needed is worth it. Battery longevity is just a money factor.