Cell Replacement procedure for APC Smart-UPS SRT 2200 Battery Packs

NOTE: This article specifically the APC Smart-UPS SRT 2200 UPS Units (Model SRT2200RMXLA-NC) and the APC RBC141 Battery cartridge. Other covered models include, but are not limited to: SRT2200RMXLA, SRT2200XLA, SRT2200RMXLI, SRT2200RMXLI-NC, SRT2200XLI, SRT72BP, SRT72RMBP.

Wiring Diagram and Notes:

The RBC141 Battery Cartridge uses six (6) 12-Volt Sealed Lead-Acid (SLA) batteries, wired in series. The aftermarket replacement cell for this pack is an 12V 5.5 Amp-hour battery with F2 terminals and dimensions of approximately 3.54L x 2.76W x 3.98H.

IMPORTANT: Cells of different ages (used, new, etc) should not be used together, nor should cells with different AH or voltage ratings. ALL batteries in a cell should match, period. This also applies to refurbishing multiple battery packs within a single UPS or expansion unit.

This is a diagram (not to scale) of the wiring for this battery pack. All batteries are wired in series; it is VERY important that the connections between batteries are from red to black and vice-versa. NEVER connect a battery terminal to the other terminal of the same color; at best, this will damage the cells, and at worst, could cause the cells to violently erupt.

The interconnections between the cells are short black cables and longer red cables. One exception is a short black cable with an inline fuse, that is placed where noted in the diagram. The longest cables run back to the plug that connects to the UPS or expansion unit, and those are colored to match the terminal they connect to: the long red cable runs from the last red terminal in the battery chain to the plug, and the long black cable runs from the first black terminal in the battery chain to the plug.


Disassembly Instructions:

There are four (4) triangle-bit security screws - two long, two short - securing the two halves of the plastic case. Additionally, once the screws are removed, there are plastic clips that will need to be pushed in so that the lid can be removed.


Triangle-bit security screw - not a tri-wing bit.


Disconnect all the battery cells, carefully remove them, and set them aside for recycling. Retain the interconnecting cables and the fuse cable, which will be re-used.


Detail of the fuse cable.


Reassembly Instructions:

Install the new cells exactly how the old ones were installed, working in reverse from the disassembly instructions. Follow the wiring diagram at the beginning of this document, and take extreme care that no battery terminals are wired to a terminal of the same color.

Once the unit is reassembled, you can verify the voltage with a multimeter. It should read approximately at or a few volts above 72 volts DC (6 Cells in series x 12 volts = 72v).

Finally, before installing the battery packs, label each with the replacement date. Take care that the label is placed so that it will not be damaged when inserted into the UPS chassis, and will be obvious when the cells are replaced or inspected (Image is from a APC SMT 3000 unit.)

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