Voltronic Power Axpert VP 3000-243kW 24V off-grid inverter/charger with 50A PWM solar charger

Overview

The Axpert VP 3000-24 is a 3kW off-grid inverter/charger for 24V lead-acid battery banks with a 50A PWM solar charger and a 25A mains or generator charger, for up to 70A of combined charging. The PV input takes up to 1,200W with an open-circuit limit of 80V and a 30–32V operating window, and Voltronic's sizing example uses one 60-cell module per string. Surge capacity is 6kVA for five seconds, and Voltronic suggests a battery of at least 100Ah. Only lead-acid batteries are supported, with AGM, flooded and user-defined profiles.

• 1kVA at 12V, 2–3kVA at 24V, 5kVA at 48V
• VP models: 50A PWM solar charger
• Utility or generator input with automatic restart
• Surge capacity twice the rating for 5 seconds
• AGM, flooded or user-defined charging profiles
• USB and RS232 monitoring, optional anti-dust kit

How it works

The Axpert V range covers simple inverter/chargers that supply 230VAC pure sine power with an output power factor of 1, charge the battery from the mains or a generator and also from PV. VP models use a 50A PWM solar charger, VM models an MPPT charger. The output can be set to utility first, solar first or SBU priority, and charging to solar first, utility first, solar and utility together or solar only.

Key features

With PWM charging the PV string voltage must be matched to the battery: Voltronic gives an operating range of 15–18V on 12V systems and 30–32V on 24V systems, with open-circuit limits of 55V and 80V, and Voltronic's sizing examples use one module per string, adding strings in parallel. Surge capacity is twice the rated power for five seconds, line-mode efficiency is above 95%, and a cold start function lets the unit start from the battery with no AC present.

Installation and compatibility

The safety notes allow only deep-cycle lead-acid batteries, with profiles for AGM, flooded and user-defined charging, and Voltronic suggests at least 100Ah of capacity for the 1–3kVA models. A separate DC protection device is required between battery and inverter, a DC breaker on the PV line and an AC breaker on the input: 10A for 1kVA and 32A for 3kVA. Leave 20cm at the sides and 50cm above and below on a non-combustible wall.

Monitoring and settings

All parameters are set from the front LCD and buttons: input voltage range (90–280VAC for appliances, 170–280VAC UPS mode), maximum total and utility charging current, the voltage points for returning to grid or battery, output frequency of 50 or 60Hz and battery equalisation for flooded batteries. USB and RS232 ports connect the unit to a PC with the supplied monitoring software. An optional anti-dust kit adds filters and enables an internal temperature sensor.

Questions and answers