— UPS Runtime · Data & IT
Data hall 100 kW, 15-min hold - 140 kVA VRLA N+1
Problem. 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.
Answer. Sized up from 100 kW at 0.9 PF, the tool lands on 140 kVA on a 250 kVA-class enterprise chassis, with a single VRLA string (~48 kWh) per bank. Against the 15-minute target the single string rounds up to about 17 min at 100% load, 24 min at 75% and 41 min at 50%.
02 / In depth
How this preset reads — the engineering view.
Online double-conversion sizing begins with the real load: 100 kW at 0.9 power factor, rounded up and carried +25% to the next standard tier, gives 140 kVA - fitted here on a 250 kVA-class enterprise chassis so the frame has room ahead of the installed rating.
The runtime target is 15 minutes, and a single VRLA string of roughly 48 kWh already carries the hold: the tool reports about 17 minutes at 100% load, so the bank rounds up just past target rather than sitting under it. At lighter loads the same string stretches to about 24 minutes at 75% and 41 minutes at 50%.
Redundancy here is N+1: one installed string of runtime plus a spare module. The spare protects against a single module fault - it does not add minutes, so the quoted runtime is the hold delivered by the one working bank.
Ambient is set at 30 degrees C, right at the VRLA hot-zone threshold, so effective battery life works out at about 4.5 years - the honest figure for a room running warm at 28 to 30 degrees C, and the line item that drives the replacement plan.
What this preset deliberately does not solve
- Runtime is per single bank; the N+1 spare adds fault-tolerance, not minutes.
- At 28-30 degrees C the VRLA hot-zone puts effective life near 4.5 years - plan the replacement cycle.
- A sub-15-min hold assumes a reliable generator handover; confirm the start-and-transfer window separately.
How this preset differs from its siblings
The healthcare sibling preset chases mission-critical 2N redundancy on LFP, where a single string already clears the target by a wide margin and the second bank is a fully independent path. This preset is the tight-window case: VRLA is the right chemistry for a sub-15-min hold, the single string only just rounds past the 15-minute target, and N+1 buys one-module fault-tolerance rather than a second bank. Use this one when the generator handover, not autonomy, sets the brief.
03 / Hydrated calculator
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· Load vs runtime · Peukert-corrected
Target 15 min @ 100%
UPS sizing · VRLA (sealed lead-acid)
Enterprise — 250 kVA enterprise (Schneider Galaxy / Vertiv Trinergy)
With 1 battery string of 48 kWh each, runtime at full load lands around 17 minutes — an approximate planning figure (ambient-, Peukert- and inverter-efficiency-derated), not a final procurement spec.
Recommended VA
140 kVA
Online double-conversion · N+1 (one spare module)
Battery strings
1
48 kWh per string
Runtime @ 100%
17 min
vs 15 min target
Effective battery life
4.5 yr
at 30 °C ambient
- Runtime @ 75% load24 min
- Runtime @ 50% load41 min
- TopologyOnline double-conversion (VFI)
Assumptions driving this recommendation↓ expand
- Topology
- Online double-conversion (VFI)
- VA headroom
- 25%
- Discharge model
- Peukert with chemistry exponent
- Inverter efficiency
- 94% DC→AC (double conversion)
- Max DoD
- 80%
- Cell voltage
- 2 V
- Cells / string
- 240
- Module Ah
- 100 Ah / string (scale by string count)
- Hot-zone ambient
- 30 °C
- Arrhenius life rule
- Halves per 8 °C above hot-zone
- Redundancy
- N+1 (one spare module)
Engineering caveats
- VRLA is the default for sub-5-minute critical-load UPS — well-understood, compact, replaced every 4–5 years.
- Common enterprise tier — one extra UPS module so the bank survives one module fault without dropping load.
Operationally sensible ecosystem
Brands grouped by engineering role — not random logos.
UPS / power conditioning
Single + 3-phase + transfer
- APC Symmetra LXModular 3-phase mid
- Vertiv Liebert APMModular 3-phase mid
BESS battery
LFP packs + BMS + enclosure
- Delta LFP CabinetCommercial cabinet
- Fuji Electric LFPCommercial mid-scale
Server racks
Equipment racks + PDU + cooling
- Vertiv VRMid-enterprise rack
- Rittal TS ITEuropean enterprise enclosure
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. Refresh batteries on the conservative half of the calculated life when ambient regularly exceeds the hot-zone.
A planning link that reopens this exact configuration — not a quote.
Peukert's law isn't linear
A VRLA string rated 100 Ah at the 10-hour rate delivers only 60–70 Ah at a 1-hour rate. The model corrects for this; specifying a string at its nameplate rate is the most common UPS sizing mistake.
Heat is the silent killer
Battery life halves for every 8 °C above the chemistry hot-zone (30 °C for VRLA, 40 °C for LFP). A 35 °C summer battery room turns a 5-year VRLA bank into a 3-year bank.
LFP is not always right
For runtimes under 5 minutes, LFP is over-engineered — VRLA gives the same outcome at a smaller footprint and lower lifecycle complexity. The chemistry crossover is around 15 min of runtime.
N+1 over N for ≥ 100 kW
Above 100 kW critical load, a single module fault drops too much load to be acceptable. N+1 modular adds one extra UPS module to the bus — survives one fault without dropping load.
Pricing · written estimate after review
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Share your drawings, BOQ or project brief on WhatsApp/call +91 88110 34444 or email info@technoguru.in for a written estimate after review. Pricing depends on drawings, site conditions, system scope, brand selection, cabling stage, integration depth, commissioning, logistics, GST, approvals and support expectations — so we prepare it per project after a technical review rather than publishing standard rates.
Compare with BESS sizing· Other presets for ups runtime estimator
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