A few things I've learned about them.....please feel free to correct or add to this. Not an expert...just a frequent flyer.
Mu observations and conclusions......(ymmv)
1). Failure is often related to them drying out over time. Even though they're sealed...they vent.
2). Deep discharge (such as when the power goes out and stays out for a long time and runs the batteries down) damages the batteries
3). Periodic desulfation can extend the useful life of an SLA battery
4). Checking the water level and topping it up with DISTILLED water can greatly extend their useful life
5), Brand NEW SLA batteries often come a bit on the dry side and could use some distilled water
Point 1
Opening them (yes they can be opened) and adding distilled water once or twice a year to keep them from drying out.
Point 2
These usually aren't "deep cycle" batteries per se. Just regular lead acid batteries.
Point 3
All lead acid batteries work by sulfation and desulfation. Sometimes the don't completely desulfate through regular use
Point 4
Again, the still vent even though they are sealed and lose moisture over time. A dry battery is not a happy battery.
Point 5
I've opened brand new SLA batteries and most of the time they are what I would consider a bit on the dry side. Not AGM batteries. Just SLA.
So, let's say you have an APC XS 1300 Back-Ups unit and it is connected to your PC and a couple other items with a load of 150watts.
As long as that battery is never discharged, it "should/could" last about 3-5 years. But the moment you have a power failure and the battery discharges, lead sulfate forms on the plates. Ideally, when the power comes back on, that process is reversed and the lead sulfate is converted back into lead and deposited on the plates. That's the Perfect World. In reality, the process is never totally efficient and a bit of lead sulfate remains. Over time this sulfate hardens and becomes permanent. Removing hardened lead sulfate crystals is hard. That's why periodic desulfation works best before a lot of time has passed or before the crystals harden. I use solar panels for desulfation. They work better than the "Professional Battery Desulfator" I paid good money for.
Mu observations and conclusions......(ymmv)
1). Failure is often related to them drying out over time. Even though they're sealed...they vent.
2). Deep discharge (such as when the power goes out and stays out for a long time and runs the batteries down) damages the batteries
3). Periodic desulfation can extend the useful life of an SLA battery
4). Checking the water level and topping it up with DISTILLED water can greatly extend their useful life
5), Brand NEW SLA batteries often come a bit on the dry side and could use some distilled water
Point 1
Opening them (yes they can be opened) and adding distilled water once or twice a year to keep them from drying out.
Point 2
These usually aren't "deep cycle" batteries per se. Just regular lead acid batteries.
Point 3
All lead acid batteries work by sulfation and desulfation. Sometimes the don't completely desulfate through regular use
Point 4
Again, the still vent even though they are sealed and lose moisture over time. A dry battery is not a happy battery.
Point 5
I've opened brand new SLA batteries and most of the time they are what I would consider a bit on the dry side. Not AGM batteries. Just SLA.
So, let's say you have an APC XS 1300 Back-Ups unit and it is connected to your PC and a couple other items with a load of 150watts.
As long as that battery is never discharged, it "should/could" last about 3-5 years. But the moment you have a power failure and the battery discharges, lead sulfate forms on the plates. Ideally, when the power comes back on, that process is reversed and the lead sulfate is converted back into lead and deposited on the plates. That's the Perfect World. In reality, the process is never totally efficient and a bit of lead sulfate remains. Over time this sulfate hardens and becomes permanent. Removing hardened lead sulfate crystals is hard. That's why periodic desulfation works best before a lot of time has passed or before the crystals harden. I use solar panels for desulfation. They work better than the "Professional Battery Desulfator" I paid good money for.