MultiPlus-II Power Inverter 3000VA 12-Volt | 2X Pure Sine Wave Inverter Charger for 120 amp Battery, with PowerAssist Technology

I upgraded to the Victron MultiPlus-II for my 50A RV solar setup, and it has completely transformed how I manage power while boondocking. This unit is a powerhouse, acting as a high-quality pure sine wave inverter, a sophisticated 120A battery charger, and a lightning-fast transfer switch all in one. The build quality is exceptional, featuring a heavy-duty steel enclosure that feels professional-grade and ready for the rigors of mobile life. The PowerAssist technology is a standout; it prevents my small 2000W generator from overloading by “assisting” it with battery power during high-demand moments, like when the AC kicks on. I also utilize the secondary AC output for non-essential loads, which automatically disconnects when I’m off-grid to preserve my battery bank. Monitoring everything through the VE.Bus system provides a level of data and control that is simply unmatched by budget competitors. Pros: • Incredible Reliability: The pure sine wave output is clean enough for my sensitive home theater equipment and medical devices. • Seamless Transfer: The 50A transfer switch is so fast that my desktop computer doesn’t even reboot when I disconnect from shore power. • Future-Proof: It is fully compatible with LiFePO4 batteries and can be expanded for parallel or three-phase systems if my power needs grow. Cons: • Learning Curve: The configuration requires the MK3-USB interface and a laptop; it’s not exactly “plug-and-play” for a novice, but there are plenty of online resources to help. • Weight and Size: At over 40 lbs, it requires a very secure mounting surface and takes up a fair amount of space in a storage bay. If you are serious about a robust, long-term power solution for a van, RV, or tiny home, this is worth every penny of the investment.

I like to boondock in my RV (camping at places without hookups) but I wanted to run my 110v appliances like the TV and microwave off my 12v batteries when shore power wasn't available. In previous RVs I've jury-rigged different products together to be able to do that, but I had to manually switch over to the inverter when off-grid and then remember to manually switch back when connected to shore power. Every time I would switch, the appliances would see a momentary loss of power and lose the time and any other settings they had. With the MultiPlus-II it's all automatic, so as long as the battery has some juice in it the appliances never see a loss of power. In addition, it does some neat tricks like PowerAssist, where if you're plugged in to a low power outlet (like a typical home 15A circuit) if the electrical demand is higher (like for a 20A air conditioner) it will supply the full 15A from the home circuit, then add whatever more power is required from the battery. All seamlessly automatic, from inside the RV you don't notice any change, things just work. I can also monitor what is going on using my cell phone, and can even make some small configuration change from it. A couple of improvements I would like see: the terminals for the 110v in and out are difficult-to-use push terminals, I would much rather have nut-and-bolt connections like they use for the 12v lines. It doesn't have bluetooth built-in, you have to buy an adaptor - for the price of this unit it should be built-in. Programming the unit requires a different adaptor and needs to be done from a laptop - I would prefer to be able to fully program it using a built-in bluetooth connection. Also, it makes an annoying buzz when in battery charge mode - I don't know why, I've had many battery chargers and none of them buzzed... That said, I'm very happy with the unit and would recommend it to anyone looking to upgrade their RV 50A system for boondocking.

After my furrion mppt solar controller failed twice under warranty I decided to cut my losses. Installed Victron 3k multi plus inverter, Victron mppt solar controller, Victron energy cerbo gx and Victron gx touch 50 to power my fifth wheel via two 300ah Epoch lithium batteries and two 370 watt solar panels. . This set up is well worth the money and is working flawlessly. We now can run our trailer for hours without shore or generator power. Way cool. GO SOLAR!!

Very happy with purchase of the victron inverter. Ability to off grid camping is awesome.

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Unfortunately, I experienced a reportedly common failure in which the Victron continuously trips the GFCI on any pedestal our outlet used to charge the 5th wheel trailer. In usergroups, I found a large number of USA users experiencing this identical problem. I contacted Victron by email several times, without any resolution. Reportedly, European outlets are designed to trip at 30-40mA, while US GFCIs trip at as low as 4mA. So, after spending a dozen hours carefully installing and grounding this Victron, and 20 hours troubleshooting, I had to spend 3 or 4 hours removing it, reboxing it, and returning it. FYI, I elected to instead purchase a EcoFlow power station. A very different approach, but for a similar amount of money received additional LiFeP battery capacity, portability in which I could potentially charge other devices, and built-in 110V, 12V, and 5 V outlets. I love the EcoFlow, and wish I had done this instead of the labor intensive install and debug for the Victron. However, lots of other users love their Victron! I just never could get it to work, and essentially all pedestals or outdoor outlets will be GFCI.

Bought this unit to supplement those times when I can't get 50 amp service, it delivers! Currently (in the pic) plugged into 30 amp...it doesn't run up to the 3600 watt peak (maybe to avoid nuisance tripping of the breaker), but it "assists" off the batteries and switches over to charging once the load dissipates. I was skeptical at first due to the price but not anymore. If I sell my current 5th wheel trailer this will be the first upgrade I make to the next one. FYI (if it matters) I have 400AH of lithium batteries on-board.

Received 7 months ago. Relatively easy to install and use. Has been excellent. Seamless going from shore power to battery (solar powered). Can operated on 50, 30, or 15 amp 120v with the internal controls automatically utilizing battery power as needed based on load requirements.