— UPS Runtime · Commercial IT
Commercial server room 20 kW, N - single VRLA string, short hold
Problem. A commercial server and BMS room carries a modest 20 kW load and only needs a short, dependable hold to ride through brief outages or allow an orderly shutdown, on a single UPS with no redundancy. The design question is which chemistry and how many strings a short target actually calls for, not how to stretch autonomy.
Answer. Sized up from 20 kW at 0.9 power factor, the tool lands on 30 kVA on a 60 kVA-class modular frame with a single VRLA string (~48 kWh) in an N (no-redundancy) arrangement. Against the 10-minute target that one string comfortably overshoots - about 108 min at 100% load, 144 min at 75% and 217 min at 50% - so the design lever here is chemistry life and footprint, not more minutes.
02 / In depth
How this preset reads — the engineering view.
Online double-conversion sizing starts with the real load: 20 kW at 0.9 power factor, rounded up and carried +25%, gives 30 kVA, placed on a 60 kVA-class modular frame so the cabinet has headroom ahead of its installed rating.
The runtime target is a short 10-minute hold, but the smallest practical battery string already carries far more: the tool reports about 108 minutes at 100% load on a single ~48 kWh VRLA string, rising to about 144 minutes at 75% and 217 minutes at 50%. The lesson this preset teaches is that at a modest load the minimum sensible string overshoots a short target by a wide margin, so runtime is not the thing to optimise - chemistry, life and redundancy are.
Redundancy here is N: one installed string, no spare module and no second path. That is the honest configuration for a commercial room where a short outage window is acceptable and the budget does not carry a redundant bank - the quoted runtime is the hold delivered by the single working string.
Ambient is set at 28 degrees C, a typical air-conditioned commercial room. VRLA is the economical chemistry at this duty, and at 28 degrees C its effective life works out at about 4.5 years - the figure that drives the replacement plan and the main reason to weigh VRLA against a longer-life chemistry if the room runs warmer or the refresh interval matters.
Final UPS make, model, string count and chemistry are selected after the electrical drawings, load schedule and generator or shutdown strategy are reviewed and remain subject to project requirement, consultant or client approval and availability. Use the brief wizard or /contact to route a safe enquiry summary to TechnoGuru's power and IT-infrastructure scope.
What this preset deliberately does not solve
- N has no redundant module or bank; a single fault drops the protected load - confirm that risk is acceptable.
- At 28 degrees C the VRLA effective life is near 4.5 years; a warmer room shortens it and moves the replacement cycle.
- The single string far exceeds a 10-min hold; treat runtime as met and decide chemistry and redundancy on other grounds.
How this preset differs from its siblings
The data-hall sibling is a tight sub-15-min VRLA hold on N+1 where the string only just rounds past target, and the hospital sibling is a 2N LFP design for mission-critical continuity. This preset is the simplest corner of the tool: a modest load, a short target, a single VRLA string with no redundancy, where even the minimum string overshoots the hold and the real decisions are chemistry life and footprint. Use it when a short, single-UPS hold is genuinely enough.
03 / Hydrated calculator
Try the configuration — live.
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— Estimator · UPS runtime
Runtime is not linear — model it.
Critical load, target runtime, ambient and chemistry in — recommended VA tier, battery string count and the Peukert-corrected runtime curve out. A planning figure, not a procurement spec.
Recommended UPS
30 kVA
online double-conversion · N (no redundancy)
Battery strings
1
48 kWh per string
Runtime @ 100%
108 min
vs 10 min target
Effective battery life
4.5 yr
at 28 °C ambient
A planning link that reopens this exact configuration — not a quote.
- tier
- Modular cabinet — 60 kVA modular (Vertiv APM / Schneider Galaxy VM)
- runtime @ 75%
- 144 min
- runtime @ 50%
- 217 min
- topology
- Online double-conversion (VFI)
- va headroom
- 25%
- discharge
- Peukert with chemistry exponent
- inverter eff
- 94% DC→AC (double conversion)
- max dod
- 80%
- cell voltage
- 2 V
- cells / string
- 240
- module ah
- 100 Ah / string (scale by string count)
- life rule
- Halves per 8 °C above the 30 °C hot-zone
+ Model assumptions (8)− Model assumptions
Indicative — kVA, string count and runtime are concept-level planning figures, not a procurement BOQ. Production sizing uses the manufacturer’s published runtime tables, which take cell ageing, charging-current limits and string-balancing into account.
What changes this estimate
- Measured load profile — peaks, ramps, harmonics
- Real battery-room ambient across summer
- Manufacturer runtime tables for the shortlisted unit
- Generator-start coordination window
Engineering notes
VRLA is the default for sub-5-minute critical-load UPS — well-understood, compact, replaced every 4–5 years.
Single UPS, single string. Acceptable for non-critical load or where a single battery-swap window is tolerable.
A planning link that reopens this exact configuration — not a quote.
· Other presets for ups runtime estimator
UPS Runtime · Data & IT
Data hall 100 kW, 15-min hold - 140 kVA VRLA N+1
A 100 kW data hall at 0.9 power factor needs a short, dependable battery hold while the standby generator starts and takes load. The design brief is a tight battery-to-generator handover, not a long autonomy window.
UPS Runtime · Healthcare / critical
Hospital 40 kW, 2N - 60 kVA LFP, two banks, ~64 min
A 40 kW critical-care load at 0.9 power factor needs mission-critical continuity with no single point of failure. The design driver is a fully redundant power path, not a longer battery window.
· Next
Brief us on the project — with this configuration.
Presets are a typology starting point. The brief wizard captures the room geometry, programme and constraints we need to translate this configuration into a real design.