A battery expansion request needs a specific operating requirement: which equipment must remain powered, what it must accomplish, and how long that response takes. Put that requirement beside the installed UPS ratings and its manufacturer’s runtime data before choosing additional battery modules.
Write down the outage response that needs power
Start with the services supported by the UPS. For each one, name the owner and the expected response to a supply interruption. A service may need time to complete an orderly shutdown, preserve in-progress work, or continue through an approved transfer to another supply. Record the sequence and the dependencies that must remain available while it runs.
Include the equipment needed to carry out that response. For example, if a shutdown instruction travels over the management network, its switching equipment belongs in the review. If someone must make a decision, record how they receive the alert and who covers the task outside normal working hours.
Use observed timings from suitable exercises or application procedures where available. Mark untested durations as estimates and give them an owner. A runtime target is easier to review when the team can explain what happens during that interval and what remains uncertain.
Record the installed power rating before requesting batteries
Capture the UPS model, its watt and volt-ampere ratings, the connected equipment, and the approved operating limits for the installation. Eaton’s UPS buying guide explains that battery additions leave the UPS power rating unchanged. It also distinguishes the watt and VA figures that appear in product specifications.
This creates two entries in the purchase review: the load the UPS must support and the duration for which it must support it. Check each against the exact model and proposed configuration. When the equipment inventory grows, revisit both entries.
Retain how the load figure was obtained. A value observed during ordinary processing, a manufacturer specification and a forecast for new equipment have different purposes. Label them clearly so the reviewer can choose the appropriate evidence for the intended operating condition.
Save the runtime curve and its assumptions
Use the manufacturer’s runtime information for the installed UPS and compatible battery configuration. Keep the selected load point, the battery-module quantity and the referenced document or page in the review record. Avoid carrying a runtime value over from a different model merely because the headline power rating looks similar.
The manufacturer’s qualifications matter. Eaton’s SU5000RTFMB runtime page, for example, presents runtime against load and identifies equipment, configuration, battery age and temperature as sources of variation. That page illustrates the kind of evidence to collect; the model is not a recommendation for another installation.
Ask the reviewer to document how the published estimate relates to the batteries currently installed. Record known battery service history and environmental observations, along with any information the manufacturer or service provider still needs. Keep an unresolved condition visible in the decision rather than silently treating the published estimate as a verified result for the site.
Give procurement a complete configuration request
A practical purchase brief can be short while still preserving the information required for approval:
- Required service: the equipment and response sequence that must remain powered.
- Duration: the required interval, its basis and any timing still awaiting verification.
- Installed configuration: UPS model, existing battery modules and available service records.
- Proposed configuration: manufacturer-confirmed compatible parts, quantities and installation requirements.
- Load and runtime evidence: the values used, their source and the conditions they describe.
- Acceptance owner: the person responsible for confirming the installed configuration and reviewing the outcome.
Have the appropriate facilities and electrical personnel review the installation requirements before placing the order. Keep the approved bill of materials linked to the operating requirement. If the available product or battery configuration changes during procurement, return that difference to the reviewer.
Plan how the team will accept the installation
Agree on the acceptance evidence before installation. That may include confirmation of the installed model and battery quantity, configuration records, manufacturer-prescribed checks, and an approved exercise of the service response. The site’s responsible personnel should choose the method, operating window and restoration conditions.
Keep application timing separate from battery test results in the record. A successful shutdown exercise supplies evidence about the response sequence. A battery or UPS check supplies evidence under its own stated conditions. Record what each check covered so a later equipment change can be assessed against the right baseline.
Close the request with the accepted configuration, the supporting results and the date for any remaining follow-up. Preserve the runtime requirement with the equipment inventory so it is reconsidered when the supported load or outage procedure changes.
Sources
- Eaton — UPS Buying Guide for Network ClosetsPublication date not stated. Retrieved October 17, 2026.
- Eaton — Battery Runtimes for SU5000RTFMBPublication date not stated. Retrieved October 17, 2026.