The Mastervolt CombiMaster 24/3500 Inverter/Charger is the cornerstone of reliable, on-demand power for boats, RVs, or off-grid systems. With a 24 V DC input and a 120 V AC output, this compact powerhouse delivers true sine-wave power up to 3500 W continuously, with ample headroom for peak and surge loads.
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Compact, lightweight and quiet — the smallest and lightest Combi in its class, delivering reliable, hum-free operation from your batteries.
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Hefty performance — continuous 3500 W at 40 °C (cos φ 1), peak 5250 W, surge 7000 W, ensuring even heavy or sensitive devices start with ease.
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Smart charging — intelligent 3-step+ battery charger with up to 100 A charge current (at 28.5 V, configurable) and a 32 A max input current (adjustable) for faster, safer charging from 90–140 V mains.
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Automatic transfer between mains, generator, and inverter — ensures uninterrupted power with seamless switching and Power Assist to prevent tripping on weak land lines or small generators.
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Generator friendly — designed to work harmoniously with generators and mains supplies alike, preventing nuisance outages and voltage dips.
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Advanced system integration — built-in communication with MasterBus, CZone, and NMEA 2000 for broad monitoring and control across your network.
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Scalable power for larger systems — supports parallel and split-phase configurations for applications up to 35 kW with the 3500/4500/5000 models.
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Rugged, reliable design — IP23 protection, vario cooling fan, and a compact footprint: 22.4" x 14.1" x 6.7" weighing 37.5 lb.
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Battery and power management — automatic voltage sensing with compensation, a battery temperature sensor included, and a configurable UoUo charging characteristic suitable for flooded, Gel/AGM, and MLI batteries.
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Energy efficiency — up to 93% max efficiency, with a 25 W energy-saving mode and a no-load draw of 0–47 W depending on mode.
The CombiMaster's automatic AC transfer system switches between mains, generator, and inverter outputs to keep a steady power supply, while its Power Assist feature protects your shore power connection from overloads. Built with user-friendliness in mind, it combines robust hardware with sophisticated control to handle everything from routine charging to demanding loads—all wrapped in a compact, quiet, and highly reliable package.
Key specifications at a glance
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Nominal DC voltage: 24 V (20.4–32 V)
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Output: 120 V, 60/50 Hz configurable, true sine wave
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Continuous power: 3500 W; Peak 5250 W; Surge 7000 W
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Efficiency: up to 93%
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Input/charger: 90–140 V, 32 A max input, 100 A max charge at 28.5 V
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Transfer: AC input up to 50 A, AC output up to 85 A
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Temperature range: −25 °C to 60 °C (derating above 40 °C; shutdown above 60 °C)
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Protection: IP23, vario fan, compliant with ABYC A31, UL1236, UL1741, SAE J1171
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Battery: recommended 200–1000 Ah; battery temperature sensor included
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Dimensions/Weight: 22.4" x 14.1" x 6.7" / 37.5 lb
Whether you’re powering a compact system or a larger install requiring parallel operation, the Mastervolt CombiMaster 24/3500 Inverter/Charger delivers dependable power, intelligent charging, and seamless integration—making power dips and failures a thing of the past.
| Specifications sine wave inverter |
| Nominal DC voltage |
24 V (20,4—32 V) |
| Output voltage |
120 V |
| Output frequency |
60/50 Hz (configurable) |
| Output waveform |
true sine |
| Continuous power at 40 °C / 104 °F, cos phi 1 |
3500 W |
| Peak power (30 sec) |
5250 W |
| Surge power (5 sec) |
7000 W |
| Max. efficiency |
93 % |
| Battery no-load power consumption |
47 W (on mode) / < 1 mA (off mode) |
| Energy saving mode consumption |
25 W |
| Synchronise with mains |
yes |
| Specifications battery charger |
| Input voltage range |
90—140 V |
| Max. input current |
32 A (adjustable) |
| Max. charge current at 40 °C / 104 °F |
100 A at 28.5 V (configurable) |
| Battery temperature sensor |
yes, included |
| Battery voltage sense |
automatic compensation |
| Specifications transfer system |
| AC input |
50 A (switched) max |
| AC output |
85 max A |
| AC input fuse |
Yes |
| Transfer voltage range |
90—140V |
| Transfer frequency range |
Transfer frequency range |
| General specifications |
| Galvanic isolation |
Yes |
| Display/read-out |
LED display |
| Dimensions, hxwxd |
22.4 x 14.1 x 6.7 inch |
| Weight |
37.5 lb |
| Compliance |
ABYC A31, UL1236, UL1741, SAEJ1171 |
| Technical specifications |
| Charge characteristic |
UoUo, automatic / 3-step+ for flooded, Gel/AGM and MLI, configurable |
| Recommended battery capacity |
200-1000 Ah (based on gel batteries, may differ for other types) |
| Temperature range (ambient temp.) |
-25°C to 60°C, derating above 40°C, shutdown above 60°C °C -13 °F to 32 °F |
| Cooling |
vario fan |
| Protection degree |
IP23 (vertical mounting) |
| Humidity protection |
conformal coating, max. 95 % relative humidity, non condensing |
| Protections |
over-temperature, overload, short circuit, high/low battery voltage |
| Power Assist |
yes, supports AC input with power from the battery |
| Power Sharing |
yes, allows you to select AC Input fuse setting |
| MasterBus compatible |
Yes |
| CZone / NMEA 2000 compatible |
Yes |