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Rectangular sealed lead-acid battery block, dark grey plastic case with two terminal posts on top

BatteryJack inc.

BatteryJack inc. SLA21-BTI UPS replacement battery

SKU CH-3A3V-ST432

Replacement UPS battery with AGM technology and 100% OEM compatibility for APC RBC21 units

  • Advanced AGM technology prevents electrolyte leakage
  • 100% OEM replacement fits APC RBC21 units
  • Maintenance-free design requires no water or gravity checks
  • Gas recombination recovers over 90% of generated gas
  • Expected service life spans 4-7 years

Direct APC RBC21 replacement

The BatteryJack inc. SLA21-BTI is a sealed lead-acid unit built to replace the APC RBC21 cartridge in compatible uninterruptible power supplies. It uses absorptive glass mat construction to deliver maintenance-free operation for server rooms, network closets and critical workstations.

Sealed AGM design runs without venting

The absorptive glass mat system recombines over 90 percent of generated gas and prevents electrolyte escape, so the battery operates safely in any orientation. Expected service life spans 4-7 years under normal float conditions with no watering or specific-gravity checks required.

Drop-in cartridge fits existing tray

The 100 percent OEM-compatible form factor slides into the UPS without tools or wiring changes, restoring runtime immediately. A three-year warranty on UPS and backup devices covers the replacement, while the non-spillable classification simplifies transport and storage.

Highlights

  • Advanced AGM technology prevents electrolyte leakage
  • 100% OEM replacement fits APC RBC21 units
  • Maintenance-free design requires no water or gravity checks
  • Gas recombination recovers over 90% of generated gas
  • Expected service life spans 4-7 years

Specifications

No published specifications for this item yet.

Questions about this item

How do I install the SLA21-BTI battery in my APC UPS and which step is often missed?

Power off the UPS, open the battery compartment, disconnect the old battery leads, connect the new battery matching the original polarity, then close the cover and power on the unit. The step people skip is verifying the lead polarity before tightening the terminals.

What maintenance or replacement will the SLA21-BTI need during its service life?

The battery is maintenance-free; no water or specific-gravity checks are required. Plan to replace it after the expected 4-7 year float life when runtime drops below your needs.

What limit appears first when the SLA21-BTI runs under sustained load?

Gas recombination handles over 90 % of generated gas during normal use; sustained heavy discharge can exceed that recombination rate, causing internal pressure to rise and triggering the safety vent.

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