Which model handles a wider or more demanding input voltage range?

The SRT6KRMXLI accepts input voltages from 100 V to 275 V, giving it a 175 V operating window. This broad low-end tolerance is well suited to locations where utility supply can dip significantly — common in developing markets or older commercial buildings.

The SRT6KRMXLIM narrows the minimum input to 160 V, accepting a 115 V window (160–275 V). This tighter floor reflects the marine variant's design assumption: shipboard generators and shore power in certified marine environments typically maintain tighter voltage bands, reducing the need for wide low-end accommodation.

For deployments where severe under-voltage events below 160 V are possible, the SRT6KRMXLI's 100 V minimum input provides a meaningful operational advantage. Both models share the same maximum input of 275 V and the same input frequency range of 40–70 Hz.

Which model provides better documented output power quality and efficiency?

The SRT6KRMXLI specifies an efficiency rating of 94.4%. This is the only model of the two for which an efficiency figure appears in the provided specifications. The SRT6KRMXLIM does not include an efficiency rating in the supplied spec data, making a direct numeric comparison impossible from the available information.

On output power quality, the SRT6KRMXLIM explicitly lists an Output Voltage Total Harmonic Distortion (THD) of 3%. This figure is absent from the SRT6KRMXLI's provided specifications. A 3% THD is a strong indicator of clean sine wave output, relevant for sensitive loads such as active PFC power supplies in servers and telecom equipment.

Both units deliver a true sine wave output, share a 3:1 crest factor, and operate across 50/60 Hz output frequency. The divergence in what each manufacturer has disclosed per model means buyers must weigh a known efficiency figure (SRT6KRMXLI) against a known THD figure (SRT6KRMXLIM) rather than a clean apples-to-apples comparison.

Which model offers stronger autonomous and safety-critical operational features?

The SRT6KRMXLIM specifies auto-restart capability, which allows the UPS to automatically resume operation after a utility power restoration without manual intervention. This is critical in unattended or remote environments — marine vessels, offshore platforms, or unmanned edge sites — where staff may not be present to manually restart equipment after a power event. The SRT6KRMXLI does not list auto-restart in its provided specifications.

Both models include Emergency Power Off (EPO), audible alarms, and surge protection rated at 480 J, placing them on equal footing for fundamental safety and alerting requirements. Noise output is identical at 55 dB for both units.

For installations requiring lights-out operation or certified marine deployment, the SRT6KRMXLIM's documented auto-restart is a meaningful differentiator. For installations in occupied facilities where manual intervention is feasible and broad input voltage tolerance is a higher priority, the SRT6KRMXLI's wider 100–275 V input range becomes the more relevant operational feature.

Which should you choose: the SRT6KRMXLI or the SRT6KRMXLIM?

Our take: The SRT6KRMXLI is the stronger choice when the deployment site experiences input voltages below 160 V or when a documented efficiency figure (94.4%) is required for energy audit or data center compliance purposes. Conversely, the SRT6KRMXLIM is the appropriate selection for marine, offshore, or unattended edge deployments: it adds auto-restart (absent from the SRT6KRMXLI spec sheet), discloses a 3% output voltage THD for sensitive-load validation, and is purpose-built to a marine certification standard. The SRT6KRMXLIM's minimum input floor of 160 V (vs. 100 V) is a deliberate design trade-off, not a deficiency, reflecting the tighter voltage environment of certified marine shore power and generator systems. Both units are otherwise electrically equivalent at 6000VA/6000W, 480 J surge, sine wave, 3:1 crest factor, and 55 dB noise. Platform qualifier: standard commercial data centers and IDF/MDF rooms favor the SRT6KRMXLI; vessel, offshore, and unmanned remote sites favor the SRT6KRMXLIM.

Side-by-Side Comparison

Spec-for-spec, from manufacturer data.

Frequently Asked Questions

Related Resources

• APC by Schneider Electric SRT6KRMXLI product page — full specs and to add to a quote
• APC by Schneider Electric SRT6KRMXLIM product page — full specs and to add to a quote