Smart-UPS 10KW Batteries last two years at best

[mlewis_apc]

I have an old apc smart-ups RT 10kw system that's been running fine for many years. It still seems to have life left so I keep it in use.

The problem is that it needs new batteries every couple of years, all 32 of them.

What's odd is that the UPS might get used 2 or 3 times in a couple of years and it's only for two minutes at a time because there is a generator that kicks in.

Does this sound normal to anyone else using these?

[mikeinnyc]

Just replaced my 16x batteries with 5k series. I did a complete run-down test and timed it. I was at "3 minutes exactly" with the stock batteries which was not enough time. My APC screen gave me a different run-down expectancy which was wrong. These batteries lasted 5 years.

New replacements 16 replacement batteries gave me 6 minutes 42 seconds at 50 % load. Since I have my generator outside this is just enough time. No need for me to load up on expensive batteries when my Generator is ready to go.

Honestly, get the battery sized to the generator run time plus 20 percent. I'll take good old fossil fuel to lead acid batteries any day.

Whatever you don't recondition the sealed lead acid batteries like on youtube. Remember, this is going inside a living space. Hope this helps.

[mlewis_apc]

Well, it's interesting input but no, it doesn't help to know why the batteries only last a couple years.

As I mentioned, I too have a generator which comes on 60 seconds after a power failure so at most, the UPS sees a load for that amount of time, maybe 2-3 times a year. I've never seen the batteries get depleted because the geny comes on.

So I'm still in the dark on why the batteries don't last longer.

[Guinea_Pig]

Check the battery temperature (if the UPS has an NMC installed this will tell you) - anything over 25C will degrade overall battery life.  Temperature is the most common cause of short life.

The way the batteries are charged can also seriously effect the life of the battery.  High current ripple or high voltage from the charger can be an issue, however in this case I doubt that the UPS charger could fail in such a way as to cause this issue without having some sort of alarm.

In my experience it is always a heat / ventilation issue on SRT UPS so it would be interesting if this is different.

Set the battery test period up (if it has one - depends on the exact SRT model I think) to give the batteries some "exercise"

Regards

[mlewis_apc]

Unfortunately, heat would not be an issue either. It's installed in a small equipment room that has good ventilation. Ambient temps never get higher than 78. Fans and AC automatically kick in.

It seems there is not going to be a way to know why but it's worrying me about buying any more of these large UPS's. I also have a number of 3KW ones that have never shown such problems.

[mikeinnyc]

Law of physics - This is a chemical reaction where the plates eventually become sulfated.

[mlewis_apc]

That's great info but doesn't answer my question :).

No reason at all batteries should die in two years barely being used. They should last at least 3-4 years like all my other APC backup devices do.