APC by Schneider Electric G35T20KF3B4S MGE Galaxy 3500 20KVA Tower UPS
Overview
The G35T20KF3B4S is a 20 kVA / 16,000W three-phase-input tower UPS from APC's MGE Galaxy 3500 line, designed for mid-range data centers, server rooms, and critical infrastructure environments where clean, regulated 208V power is non-negotiable. It ships with three battery modules installed and is field-expandable to four, giving you a built-in growth path without replacing the main unit. If you're sizing a UPS for a network equipment room or a compact server deployment running 15–18kW of load, this is a unit worth evaluating carefully.
Key Features
- 20 kVA / 16,000W Output Capacity: At 16kW of real power delivery, this unit handles dense server racks or multiple network closets. The gap between VA and watts (80% power factor) is already factored in — 16kW is what you actually get to load, not a marketing headline figure.
- 93% Operating Efficiency: At 93% efficiency, you're losing roughly 1.2kW to heat at full load. That directly reduces your cooling burden and lowers operating costs compared to older UPS designs running at 88–90%. Over a three-year run at $0.10/kWh, the difference adds up to hundreds of dollars in energy savings.
- Hot-Swap Battery Modules: The battery modules can be replaced under load — no scheduled downtime, no maintenance window required. For 24/7 facilities, this is a practical necessity, not a luxury. Sealed Lead Acid (VRLA) chemistry keeps maintenance simple with no water topping or venting requirements.
- 5-Hour Battery Recharge Time: After a full discharge event, the system returns to full runtime capability within 5 hours. Plan your maintenance windows and generator test cycles accordingly — back-to-back outages within that window leave you partially exposed.
- 3 Battery Modules Standard, Expandable to 4: The fourth battery slot gives you an in-place runtime extension without a forklift upgrade. Add the fourth module as your load grows or your runtime requirements change — common in edge deployments where generator start times are longer.
- Output Voltage THD of 4%: Total harmonic distortion on the output is held to 4%, which is well within the tolerance of sensitive server power supplies and networking hardware. Higher THD causes premature PSU wear and can trigger nuisance shutdowns on finicky equipment.
- 51.3 dB Noise Level: At 51.3 dB, this unit is quieter than a typical office conversation. Practical for installations in mixed-use spaces — wiring closets adjacent to occupied offices — without requiring acoustic treatment.
- RS-232 Management Port: The onboard RS-232 port enables direct integration with building management systems or UPS monitoring software for real-time status, alarm forwarding, and graceful shutdown coordination. In a data center environment, unmonitored UPS hardware is a liability.
- Operating Range 0–40°C: The unit operates cleanly across the full 0–40°C range, covering everything from cold server rooms to warmer industrial equipment closets. Storage tolerance extends to -15°C, relevant if the unit ships through cold climates in winter.
- Tower Form Factor, Silver Finish: The tower chassis works for floor placement in server rooms and wiring closets where rack space is at a premium. It won't fit a standard 19-inch rack without a conversion kit — verify your space before ordering if rack integration is required.
Integration and Compatibility
The G35T20KF3B4S connects to management infrastructure via RS-232, compatible with APC's PowerChute software and most third-party BMS/DCIM platforms that support serial UPS protocols. The single AC outlet configuration is designed for downstream PDU distribution — you're not plugging individual servers directly into this unit. Pair it with a compatible rack PDU for proper load distribution across your equipment. Operating altitude ceiling of 999.9m (approximately 3,280 ft) should be noted for high-elevation deployments; consult derating guidelines above that threshold.
Frequently Asked Questions
Q: What is the real power output of the G35T20KF3B4S — is it 20kVA or something lower?
A: The G35T20KF3B4S delivers 16,000W (16kW) of real power at a 0.8 power factor. The 20 kVA rating is the apparent power. When sizing your load, use the 16kW figure — that's the usable wattage available to your equipment.
Q: Can I replace batteries on the G35T20KF3B4S without taking it offline?
A: Yes. The G35T20KF3B4S supports hot-swap battery replacement, meaning batteries can be swapped while the unit remains online and powering your load. No maintenance window or equipment shutdown is required for battery service.
Q: How long does it take for the G35T20KF3B4S to recharge after a full discharge?
A: Recharge time after a full discharge is 5 hours. If you experience a full-drain event, plan for a 5-hour window before the unit returns to full runtime capacity. Avoid back-to-back outage scenarios within that recharge period.
Q: Does the G35T20KF3B4S come with all four battery modules installed?
A: No. This configuration ships with 3 battery modules installed. The chassis supports up to 4 modules, so one additional battery slot is available for a field upgrade to extend runtime without replacing the main unit.
Q: What management interfaces does the G35T20KF3B4S support?
A: The G35T20KF3B4S includes one RS-232 serial port for management connectivity. This supports integration with UPS monitoring software and building management systems. Network management card expansion should be verified against APC's compatibility documentation for this model.
Q: Is the G35T20KF3B4S suitable for rack mounting?
A: The G35T20KF3B4S is a tower form factor unit, not a native rack-mount chassis. Floor placement is the standard installation. If rack integration is needed, verify rack conversion kit availability and dimensional compatibility before purchasing.
The G35T20KF3B4S sits in an interesting capacity bracket — 20 kVA / 16kW is enough to anchor a dedicated server room or protect a dense edge compute deployment, but the tower form factor and 3+1 battery module architecture mean you're trading rack density for field-serviceable runtime flexibility. The 93% efficiency figure is the spec I'd lead with in any budget conversation: at full load, you're dissipating roughly 1.2kW as heat, which directly reduces your cooling infrastructure requirements compared to older UPS platforms running 88–90%.
Technical Highlights:
- 16kW Real Power Output: The 80% power factor translates 20 kVA to 16,000W of usable load capacity — critical for accurate sizing. Overloading a UPS because someone confused VA with watts is one of the most common field mistakes on mid-range deployments.
- Hot-Swap VRLA Batteries: Sealed Lead Acid chemistry with hot-swap support means battery maintenance happens on your schedule, not the equipment's. No acid handling, no venting concerns — straightforward for facilities staff without specialized UPS training.
- 4% Output THD: Holding output voltage distortion to 4% matters when you're protecting server power supplies with active PFC. High THD inputs stress those PSUs and can cause nuisance tripping on higher-end compute hardware.
Deployment Considerations:
- The single AC outlet is a PDU feed point, not a direct-connect strip — budget for a compatible rack PDU in your BOM and verify current draw distribution across circuits before commissioning.
- The 999.9m altitude ceiling is a real constraint for mountain-region deployments; above that threshold, output derating applies and should be factored into load calculations before the unit ships.
This unit fits best in a dedicated server room or edge data facility running 10–15kW of continuous load, where hot-swap battery service without downtime and RS-232 management integration into an existing BMS are higher priorities than maximizing rack-unit efficiency.
