Voltronic Power Axpert MAX E Duplex 11K11kW 48V off-grid inverter/charger with dual MPPT and dual AC input

Overview

The Axpert MAX E Duplex 11K is an 11kW, 48V off-grid inverter/charger with two independent AC inputs, one for the grid and one for a generator, which it switches between automatically. Two MPPT trackers take up to 5,500W each, 11,000W in total, from strings of up to 500V open-circuit, and battery charging from solar and AC together reaches 150A. Surge capacity is 22kVA for five seconds. Its second input is intended for a generator alongside the utility supply, and up to six units can be paralleled for 66kW single-phase or a three-phase system.

• 11kW pure sine output, 22kVA surge for 5 seconds
• Two MPPT inputs: 11kW PV, 500V Voc, 90–450V
• Utility and generator inputs switched automatically, 60A each
• Up to 150A battery charging from solar and AC
• Up to 6 units in parallel, single or three-phase
• Built-in Wi-Fi, detachable LCD and BMS port

How it works

The Axpert MAX E Duplex 11K puts a 230VAC pure sine inverter, a mains/generator battery charger and two MPPT solar chargers into one wall-mounted cabinet for a 48V battery bank. What sets the Duplex apart is its second AC input: the utility supply connects to L1/N1 and a generator to L2/N2, each accepting up to 60A, and the unit selects between them automatically while the loads stay connected to a single AC output.

The output source priority is chosen on the LCD: utility first, solar first, or SBU, where solar is used first, then the battery, and the grid only when the battery reaches the set voltage or SOC. Battery charging can come from solar only, solar first, utility first or both together, with a separate current limit for the utility and the generator input. The unit can also run without a battery when PV or AC is present.

Key features

Each PV input accepts up to 27A and 5,500W (40A combined), giving 11,000W across both trackers. The MPPT range is 90–450V, the start-up voltage 80V and the open-circuit limit 500V. Total charging current, solar plus AC, is adjustable up to 150A. The inverter delivers 11kW continuously, twice that for five seconds, with 93% peak efficiency and voltage THD below 5% on linear loads. Output voltage is selectable at 220, 230 or 240V and 50 or 60Hz.

Installation and compatibility

Voltronic's wiring table lists 228A typical battery current, a 250Ah reference battery, 3/0AWG (85mm²) cable with ring terminals torqued to 5Nm and a 250A/70VDC breaker per unit. The PV side needs a 600VDC/30A breaker and a junction box with surge protection; as the unit is non-isolated, only class A mono or polycrystalline modules or ungrounded CIGS modules may be used. Mount it vertically on a non-combustible wall with 20cm clearance at the sides and 50cm above and below.

Battery profiles cover AGM, flooded and user-defined lead-acid, plus Pylontech, WECO and Soltaro lithium, a LIb-protocol setting and a generic lithium setting; with lithium selected, the switching points become SOC values. Up to six units run in parallel for 66kW single-phase, or as a three-phase system with up to four units per phase. Parallel systems require a connected battery and battery cables of equal length.

Monitoring and settings

Built-in Wi-Fi connects the inverter to the WatchPower app for iOS and Android. The LCD module can be removed and mounted elsewhere with an optional RJ45 cable. Other ports are USB with On-the-Go for firmware updates and data log export, RS232, a BMS port (RS485, CAN or RS232) and a 3A/250VAC dry contact that switches on battery voltage thresholds. An RGB LED bar shows the energy source and battery status, and up to 1,440 log entries are stored.

Questions and answers