Inverter vs Inverter-Charger: Which One?

An inverter-charger is an inverter with two extra parts: a battery charger and an automatic transfer switch. When mains or generator power appears it passes the mains straight through to your appliances and recharges the bank at the same time, then switches back to inverting when the external AC goes away. If your system regularly sees mains, a marina, powered sites, a generator, the combination usually earns its price. If it never does, a plain inverter plus the right DC charging is cheaper, simpler and easier to make safe and compliant.

What the transfer switch buys you is one set of 230V wiring. Without it, a camper or a boat with shore power needs either a manual changeover or two circuits, one fed by the inverter and one by the shore lead, and a human who never forgets which is which. The inverter-charger sits at the junction: the appliances plug into it once, and the machine decides whether they're fed from the battery or the shore lead. Our PassPower 3000W transfers in 8ms and the Mustpower Plus 2000W in 10ms, fast enough that electronics don't notice. On a boat or caravan that moves between powered and unpowered nights, that makes it an automatic system rather than a routine you have to remember.

The built-in charger is the other half of the job. The PassPower 3000W charges at 75A on 12V (35A on 24V) and the Mustpower Plus 2000W at 60A (30A on 24V), both adjustable, in four charging stages, so every hour on a generator or a powered site puts real charge back, faster than the portable charger the same owner would have bought. Some of our stackable models can be paralleled, up to six units on one phase, for bigger builds; check the exact model. One thing to get straight: there are two kinds of inverter-charger in our range. The PassPower, ProFlex and Mustpower Plus units charge from mains only, so you still need a separate MPPT for panels. The solar inverter-chargers, the Mustpower PV18, Growatt and ESG units, have the MPPT built in, so one box does the inverting, the mains charging and the solar. Pick by which energy sources your system actually will have.

When a plain inverter is the smarter buy: systems that never meet mains, a ute canopy charged only by the alternator and solar, a remote shed, where the charger and the transfer switch would be installed and never used; and very small systems, where a combined unit's higher idle draw would matter more. The decision is a usage question: count the nights a year the system will see shore or generator power. More than a handful, buy the inverter-charger once rather than accumulating boxes. For an off-grid home with a backup generator, it's the piece that makes the generator automatic: generator starts, house runs on it, bank recharges, generator stops.

Browse the inverter-chargers, or ask us which kind fits your sources. More in our Inverters FAQ and on the marine page.

Common questions

Does an inverter-charger switch fast enough for a computer?

Ours transfer in 8 to 10ms, which a computer, a TV or a router rides through without a blink; it's the same job a desktop UPS does. If one load is truly interruption-critical, check the unit's stated transfer time, but for normal camper and boat electronics you won't notice it.

Can the inverter-charger run appliances and charge at once?

Yes. On mains it passes power through to your circuits and uses what's left of the shore feed to charge the bank. The charge rate is adjustable, from 100 percent down to 40 or off on the PassPower and in 5A steps on the Mustpower Plus. Be aware: if you are charging at the same time, your total AC draw will be the sum of the appliances that you are powering plus the onboard charger, so factor that in. That becomes critical if you've got a smaller generator or an amp-rate-limited cable, such as a 16-amp camper plug. Your AC current supply is capped, and you must stay within it. Turn the charge rate down to keep within that supply limit.

Is an inverter-charger worth it for an off-grid house?

If a generator is part of the design, usually yes: it automates the run-and-recharge cycle and keeps the house powered without a flicker while it happens. If the house will never see AC input, spend the difference on solar or storage instead.