The short answer. A MultiPlus is an inverter, a shore charger and a transfer switch in one box. Pick it if you plug in to shore power or run a generator often and want one install. Pick a Phoenix inverter plus a separate charger if you want a backup when one part fails, or a smaller, simpler setup.
You’ll need
- One box: the Victron MultiPlus 12/2000/80-50 120V
- Or two boxes: the Victron Phoenix 12/1200 120V GFCI plus the Victron Blue Smart IP22 12/30 120V
- Your inverter size worked out first: Inverter size calculator
- DC cable and a battery fuse sized for the inverter: Wire gauge calculator
- A licensed electrician for anything on the AC side (panel, shore inlet, generator)
Choose in 5 steps
- Work out how many watts you run at once. The What size inverter for a boat, van or RV walks you through it.
- Ask how often you’re on shore power or a generator. Often? Lean to one box.
- Ask what happens if a part fails far from home. Want the other half to keep working? Lean to two boxes.
- Check the charger amps against your battery bank.
- Size the DC cable first, then the fuse. Leave the AC wiring to a licensed electrician.
You can do this. Most of the decision is about how you use the boat, van or RV, not the specs.
The numbers side by side
All figures come from Victron’s own datasheets and manuals for the 12V, 120V models.
| MultiPlus 12/2000/80-50 | Phoenix 12/1200 + IP22 12/30 | |
|---|---|---|
| Inverter, continuous at 25°C | 2000 VA / 1600 W | 1200 W |
| Inverter, continuous at 40°C | 1400 W | 1100 W |
| Peak | 3500 W (no time given) | 1600 W for 15 seconds |
| Max efficiency (12V) | 93% | 91% |
| Inverter idle draw | 10 W, 3 W in search mode | 11 W, about 1 W in ECO mode |
| Shore charger | 80 A, plus 1 A to a start battery | 30 A (15 A in night or low mode) |
| Charge voltages | Defaults 14.4 V / 13.8 V; change with VE.Configure or the VE.Bus Smart dongle | Li-ion mode: 14.2 V / 13.5 V |
| Transfer switch | 50 A | None |
| PowerAssist | Yes | No |
| Internal DC fuse | None | 200 A MIDI inside the Phoenix |
Two quick reads of that table. The MultiPlus gives you 400 W more continuous power and a much bigger charger. The two-box setup idles lower when the Phoenix is in ECO mode.
What does the MultiPlus do that two boxes can’t?
Three things, all from Victron’s datasheet.
A transfer switch. Victron calls it a high-speed AC transfer switch, rated 50 A. When shore or generator power comes in, it passes that power through to your AC loads and charges the battery. When it goes away, the inverter takes over. Victron doesn’t print a switch-over time on this datasheet, so we don’t quote one.
PowerControl. You set the most current your shore post or generator can give. The MultiPlus counts your other AC loads and charges only with what’s left over. That stops a small shore supply from tripping.
PowerAssist. This goes one step further. When your AC loads need more than the shore or generator supply can give, the MultiPlus adds power from the battery to cover the gap. When the load drops, the spare power goes back into the battery. Think of a small generator plus a microwave burst.
A Phoenix and a separate charger can’t share the load like this. They each do one job.
The catch is the flip side of all that: one box means one point of failure.
When two boxes win
You want a backup. If the inverter fails, the charger still charges. If the charger fails, the inverter still runs. With one box, a fault can take out both jobs at once.
Your AC loads are small. If your list fits in 1200 W, a bigger inverter only adds idle draw and DC current. The Phoenix drops to about 1 W in ECO mode.
You’d rather skip AC wiring. The Phoenix 12/1200 we list has GFCI outlets on the unit. The IP22 charger comes with a 1.8 m (6 ft) cord and a NEMA 5-15 plug. Plug in your loads, plug in the charger, done. Any connection to a panel or shore inlet still goes to a licensed electrician.
You want to place them apart. The charger is light and small. It can sit near the battery while the inverter sits near the loads.
When one box wins
You plug in often. Marinas, campgrounds, a generator. The MultiPlus switches between shore and battery for you, and its 80 A charger refills a big bank faster than a 30 A charger.
Your shore supply or generator is small. PowerControl and PowerAssist are built for exactly that.
You want one install. One set of battery cables, one battery fuse, one unit to set up. Victron’s datasheet lists up to 6 MultiPlus units in parallel if you grow later.
You run bigger loads. 1600 W continuous at 25°C covers more than the Phoenix 12/1200.
Can the charger handle my battery bank?
Start with Victron’s limits. The IP22 12/30 manual gives a maximum battery size of 300 Ah. For lithium, its minimum is 60 Ah when it charges at full current.
The MultiPlus charges at up to 80 A (Victron rates that at up to 25°C). Ask your battery maker for its maximum charge current. Then check the charger’s setting stays under it.
On lithium, use the battery maker’s charge voltages. The IP22 has a Li-ion mode at 14.2 V. The MultiPlus datasheet lists lead-acid style defaults (14.4 V absorption, 13.8 V float). You change those with VE.Configure or the VE.Bus Smart dongle. More on shore chargers in Shore power charging: Blue Smart IP22 vs IP65.
The DC side: cable first, then fuse
Isolate the battery before you touch a DC cable. Switch off, take the negative off, then work.
Both setups pull big current from a 12V bank:
- MultiPlus at 1600 W: 1600 ÷ 12 ÷ 0.93 = about 143 A
- Phoenix at 1200 W: 1200 ÷ 12 ÷ 0.91 = about 110 A
Size the cable for that current and your real run length in the Wire gauge calculator. Then pick a fuse that protects that cable. For the Phoenix, Victron’s manual gives 25 mm² cable up to 1.5 m and 35 mm² up to 3 m.
Mind the fuses. The Phoenix’s internal 200 A fuse protects the inverter, not your cable. The MultiPlus has no internal DC fuse at all. In both cases the fuse at the battery does the job. Fusing a lithium bank: Lynx, MRBF and class T covers which type goes where.
Does this guide fit your setup?
This applies if: – You have a 12V house bank on a boat, van or RV and want 120V AC. – You’re choosing between an inverter-charger and separate units.
This doesn’t apply if: – Your system is 24V or 48V. The same ideas hold, but the models above are 12V. – You need the AC side wired into a panel, a shore inlet or a generator. That part needs a licensed electrician (on a boat, look for ABYC certification too).
Products used in this guide
| Product | Why it’s here |
|---|---|
| Victron MultiPlus 12/2000/80-50 120V | Inverter, 80 A charger and 50 A transfer switch in one box. |
| Victron Phoenix 12/1200 120V GFCI | 1200 W inverter with GFCI outlets and an ECO mode. |
| Victron Blue Smart IP22 12/30 120V | 30 A shore charger with a Li-ion mode. Plugs into a standard outlet. |
Prices show live from the store. See them all in Inverters and inverter-chargers.
Quick answers
Is a MultiPlus better than an inverter and a charger? Not always. It wins on shore power, small generators and bigger loads. Two boxes win on backup and low idle draw for small loads.
What does PowerAssist do? Victron says it adds battery power when your AC loads need more than the shore or generator supply can give. When the load drops, spare power recharges the battery.
Does a Phoenix inverter charge the battery? No. A Phoenix only turns DC into AC. Pair it with a shore charger like the Blue Smart IP22.
Can I install a MultiPlus myself? The DC side, yes, following Victron’s manual for cable and fuse. The AC side (panel, shore inlet, generator) goes to a licensed electrician.
Does the MultiPlus have a lithium setting? Its datasheet lists default charge voltages of 14.4 V and 13.8 V. You set your battery maker’s numbers with VE.Configure or the VE.Bus Smart dongle.
Sources
- Victron MultiPlus 2000VA 120V datasheet: https://www.victronenergy.com/upload/documents/Datasheet-MultiPlus-2000VA-120V-EN.pdf
- Victron Inverter VE.Direct 120V manual (HW15): https://www.victronenergy.com/upload/documents/Inverter_VE.Direct_120V_-_HW15/106668-Inverter_VE_Direct__Smart_and_SUN-pdf-en.pdf
- Victron Blue Smart IP22 Charger 120 VAC datasheet: https://www.victronenergy.com/upload/documents/Datasheet-Blue-Smart-IP22-Charger-120-VAC-EN-.pdf
- Victron Blue Smart IP22 Charger 120V manual: https://www.victronenergy.com/upload/documents/Blue_Smart_IP22_Charger_120V_manual/181363-Blue_Smart_Charger-pdf-en.pdf
