Magnum Energy Pure Sine Inverter 4kW MS4048-L

The Magnum Energy MS4048-L is a 4,000VA pure sine wave off grid inverter charger operating on a 48VDC battery bank, delivering 94.0% peak inverter efficiency — the highest in the Magnum MS Series line — in the same corrosion-protected, field-proven enclosure used across the MS Series. ETL listed to UL/cUL 458, CSA C22.2 No. 107.1-01, and meeting the KKK-A-1822E emergency vehicle standard, it is built for residential off-grid, backup power, and mission-critical mobile applications where efficiency and build quality both matter.

Key specifications

• Continuous output power: 4,000VA at 77°F (25°C)
• Surge power: 8,500W (5 seconds); 5,750W (30 seconds); 5,250W (5 minutes); 4,750W (30 minutes)
• AC output voltage / frequency: 120VAC ±5%; 60Hz ±0.1Hz; THD <5%
• DC input voltage: 48V nominal (36.0–67.6VDC operating range)
• AC inputs: 2 inputs; 30AAC maximum each (60AAC total); 60–140VAC; 50–70Hz
• AC relay transfer time: 16ms
• Battery charger output: 60ADC continuous; 5-stage charging (Bulk, Absorb, Float, Equalize, Battery Saver™); PFC power factor >0.95; 85% charger efficiency
• Peak inverter efficiency: 94.0%
• Idle power consumption: 25W (inverting, no load); <8W (search mode)
• Battery temperature compensation: Standard with optional temp sensor (0–50°C)
• Internal cooling: Dual 92mm brushless DC fans, 0–120 cfm variable speed
• Certifications: ETL listed to UL/cUL 458; CSA C22.2 No. 107.1-01; KKK-A-1822E
• Operating temperature: −4°F to 140°F (−20°C to 60°C); max altitude 15,000 ft. (4,570 m)
• Enclosure: Powder-coated chassis; conformal-coated PCBs; stainless steel fasteners
• Dimensions: 13.75 L × 12.65 W × 8.0 H in. (34.9 × 32.1 × 20.3 cm); 55 lbs. (24.9 kg)
• Warranty: 3 years parts and labor

94% efficiency: the 48V advantage in the MS Series

Across the full Magnum MS Series lineup, the MS4048 consistently delivers the highest efficiency at every load point — outperforming the 12V, 24V, and 28V models throughout the operating range. At 94.0% peak, the gap between the MS4048 and lower-voltage alternatives is meaningful in continuous-use off-grid and backup applications: lower conversion losses mean longer battery runtime per charge cycle, reduced heat generation, and less demand on cooling. For systems that run the inverter continuously — off-grid homes, communications sites, and emergency vehicles — the efficiency advantage compounds over time in both energy savings and component longevity.

Battery Saver™ and 5-stage charging

The MS4048-L's integrated charger uses five stages to protect and extend battery service life beyond what standard 3-stage chargers provide. After completing Bulk, Absorb, and Float stages, the Equalize stage (activated via remote control) periodically balances flooded cell batteries to prevent stratification. Battery Saver™ mode then maintains the battery in a low-draw holding state between charge cycles, reducing unnecessary cycling and trickle current that would otherwise degrade battery capacity over time. Power factor corrected charging at >0.95 draws real, usable current from the generator rather than reactive current — resulting in more effective charging per generator amp and improved compatibility with undersized or sensitive generators.

Application scenarios

• Off-grid residential on a 48V system: 4,000VA continuous with 8,500W surge handles full household loads including motor-driven appliances, HVAC, and well pumps.
• Emergency vehicles and ambulances: KKK-A-1822E certification meets the Federal Specification for ambulance construction, supporting mission-critical mobile power installations.
• Communications and critical backup: 16ms transfer time and <8W search mode idle keep sensitive equipment powered through source transitions with minimal standby draw.
• High-altitude installations: Rated to 15,000 ft. (4,570 m) — suitable for mountain off-grid sites, remote telecom installations, and high-elevation RV and vehicle applications.
• Lithium battery systems: The "-L" designation confirms compatibility with lithium iron phosphate (LFP) and other lithium chemistries alongside flooded, gel, and AGM profiles.

Built for demanding environments

The MS4048-L uses the same corrosion-resistant construction as the full Magnum MS Series: conformal-coated PCBs, powder-coated chassis and top cover, and stainless steel fasteners protect against moisture, vibration, and the temperature cycling common in mobile, marine, and remote fixed installations. Two overlapping overcurrent protection circuits and multipoint over-temperature protection on the transformer, MOSFETs, and battery connections guard against fault conditions. Variable-speed dual 92mm brushless DC fans adjust airflow from 0 to 120 cfm based on thermal load, reducing noise at partial output while providing full cooling capacity when needed.

System compatibility

The MS4048-L operates on a 48V battery bank across 36–67.6VDC and supports lithium-ion (LFP), flooded, gel, and AGM chemistries with battery temperature compensation via the optional ME-BTS sensor. Two AC inputs each accept up to 30AAC (60AAC total) from grid or generator sources at 60–140VAC. Compatible Magnum accessories include the ME-RC50 and ME-ARC50 remote controls (required for Equalize charging stage), ME-AGS-N auto generator start, ME-BMK battery monitor kit, and ME-CB or MMP/MP combiner boxes (required if vents must face downward). The unit does not support inverter stacking.

Why choose the Magnum Energy MS4048-L?

The Magnum Energy MS4048-L is the right choice for 48V system builders who want the most efficient model in the Magnum MS Series — 94.0% peak inverter efficiency, an 8,500W surge rating, 5-stage Battery Saver™ charging, and KKK-A-1822E certification — in an ETL-listed, field-proven enclosure backed by a three-year warranty. For off-grid homes, emergency vehicle installers, and critical backup applications where conversion efficiency and long-term reliability are both non-negotiable, the MS4048-L delivers the proven Magnum platform at its highest performance point.