Actions
Forum Thread Details
  • Replies 15 replies
  • Subscribers 287 subscribers
  • Views 5060 views
  • Users 0 members are here
Related

Recondition or reuse end-of-life SLA batteries from a UPS?

baldengineer

12V Sealed Lead Acid Battery

I realize the irony of asking this question.

If a sealed lead acid (SLA) battery is at the end of its life, then it is done, right?

I have at least six 1500 VA uninterruptible power supply (UPS) units throughout my lab, studio, and house. Each UPS has two 12 volt batteries, so I have at least two batteries total. They're slowly starting to fail because the supervisor circuit has decided the batteries are at the end of their life. (Well, in fairness, they probably are!) Fortunately, drop-in replacements exist, so I can keep the UPS units running with a swap. $150 to replace all the batteries or $1200+ for new units. (Even with 2 hours of my inflated labor charge, that is a decent saving!)

Anyway.

While I'm sure they can no longer provide 10s of amps to a load, I expect they can work as a decent low-current battery backup option for one-off IoT stuff.

Is there anything I can do to recondition these batteries? Or do I just accept their current ESR and deal with it?

Or do I just take them to the recycling center and not even bother?

What would you do?

Parents

  • My experience is that they are rarely salvageable for anything useful.

    If they've been sitting in a UPS, they would likely suffer either from being dried out and bubbled up internally where adding distilled water doesn't do much. Their grids may also be malformed from corrosion that happens when sitting on float all the time.

    If they've been sitting in a dead UPS, then they would probably be sulfated to death ... which is also mostly irreversible.

    The gelled/AGM construction of SLAs generally preclude any service even though you could try. I know I have tried the same from batteries from fire-alarm panels etc but not been successful.

    (Incidentally, many low-cost UPSes nowadays are "line interactive" which is basically an AVR + offline UPS. These usually keep their batteries floating all the time.)

    - Gough

Reply

  • My experience is that they are rarely salvageable for anything useful.

    If they've been sitting in a UPS, they would likely suffer either from being dried out and bubbled up internally where adding distilled water doesn't do much. Their grids may also be malformed from corrosion that happens when sitting on float all the time.

    If they've been sitting in a dead UPS, then they would probably be sulfated to death ... which is also mostly irreversible.

    The gelled/AGM construction of SLAs generally preclude any service even though you could try. I know I have tried the same from batteries from fire-alarm panels etc but not been successful.

    (Incidentally, many low-cost UPSes nowadays are "line interactive" which is basically an AVR + offline UPS. These usually keep their batteries floating all the time.)

    - Gough

Children
  • in reply to Gough Lui

    I just went through this dance again with SLA bateries in emergency exit lights.  Shame on me for doubting what I should kinow to be true: A dead SLA is a dead SLA.  You aren't bringing it back.  I have only had 2 of 20 batteries that I was able to use after they were replaced.  That's not a good success rate.