How long do we want batteries to last ?

2oldman wrote:

skipnchar wrote:
I get over 8 years from a set of flooded cell t-105s.

At what age do you start noticing weakness? Perhaps we have different criteria for when to replace. I can notice a definite weakening at around 4 years.

I went from 2 to 4 GC so I swapped out batteries. The "old" ones were 8 year old T-125's. Gave them to my SIL's folks. SG was still 1.285, load test voltage drop test was within about 10mv (0.010v) of my new set. When we both went dry camping they held up fine. That 8 year old set was regularly discharged to 30%SOC (70%DOD) on the order of 20 times/year.

How close to new capacity?? Don't know, but based on how I usually used them, which was pretty consistent, I'd say they had lost at most 20% of original capacity.

Always made sure the battery water level was above the plates, added distilled water as needed. I just made sure when we returned from a trip they were FULLY charged before going into storage. And never let them go below 30%SOC,(70%DOD) near the lower limit recomended by Trojan. Since I used my Trimetric monitor to gauge DOD, I didn't want to push the 20% SOC (80%DOD) limit recomended by Trojan. And I would use a good SG meter (recomended by Mex) a couple of times/year and do an equalization if needed.

And that set of batteries only had a peak load of maybe 25A, usually closer to 10A.

I suspect they have several years life in them. We shall see how they hold up.

And IMHO batteries have improved significantly over the years. I just replaced the starting batteries in my Silverado Diesel after 10 years and 125K miles. And they did have a few times when it was pretty much run down to "empty" by accident. And my mercedes OEM battery was going strong after 15 years, just replaced it on general principles. Dealer said not unusual, they usually last at least 12 years, he had seen many good after 15+ years.

Don't think DW would have liked to have had it go bad on her on the way to work.