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Rectangular sealed lead-acid battery cartridge, black plastic casing with terminals on top

PowerWarehouse

PowerWarehouse LEADACIDSLA12-21 UPS replacement battery

SKU CH-JA3C-BKJ81

A maintenance-free 12 V 21 Ah lead-acid cartridge that replaces the RBC12 module in APC SU3000RMTX136 UPS units

  • Direct APC SU3000RMTX136 compatibility ensures drop-in fit
  • Maintenance-free lead-acid design removes routine upkeep tasks
  • 12 V 21 Ah capacity powers extended runtime needs
  • Replaces RBC12 cartridge #12 without configuration changes

APC SU3000RMTX136 compatible cartridge

This PowerWarehouse LEADACIDSLA12-21 battery replaces the APC RBC12 cartridge for the SU3000RMTX136 uninterruptible power supply. It is a maintenance-free sealed lead-acid unit designed for rack-mount server environments. The 12 V 21 Ah cells deliver the rated runtime for critical network and server loads.

Sustained discharge on rack-mount UPS

Under continuous load the sealed chemistry maintains stable voltage until the UPS initiates its controlled shutdown sequence. Internal resistance stays low during extended outages so the inverter receives consistent current. The valve-regulated design prevents electrolyte loss over repeated deep cycles. Installers should verify the 136 mm cartridge width matches the battery bay before ordering.

How it compares

Measured against everything we stock in UPS Replacement Batteries, at today’s prices. Recalculated every night.

Price $187.99
Pricier than about 84% of the 3,915 comparable items (median $39.99).

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Specifications

Product
Brand namePowerWarehouse
Model nameLEADACIDSLA12-21

Questions about this item

How much heat does the LEADACIDSLA12-21 generate during continuous UPS operation?

As a sealed lead-acid unit it produces minimal heat under normal float charge; ensure the UPS cabinet ventilation remains unobstructed for the 12 V 21 Ah cells.

Which existing UPS hardware is required for the LEADACIDSLA12-21 to function?

It is a direct replacement cartridge for the APC SU3000RMTX136 UPS using the original RBC12 tray; no additional hardware is needed beyond the host UPS.

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