Replacing an old RV converter with Victron gear is a popular upgrade, especially when you switch to lithium. Many older converters have fixed charge voltages that don’t suit LiFePO4, and they can’t run loads when shore power is gone. Victron offers two common paths: a Blue Smart IP22 charger for a simple swap, or a MultiPlus-II 2x120V inverter/charger for a full upgrade.
Electrical work can be dangerous: follow the manual, fuse and size every cable correctly, and use a licensed electrician for anything connected to household wiring.
Option 1: Replace the RV Converter With Victron Blue Smart IP22
If you just want better charging, the Blue Smart IP22 is the simpler swap. Victron’s datasheet lists:
- Up to 94% efficiency
- An adaptive charge algorithm, with a simple bulk-absorption-float profile for Li-ion
- Programmable voltages through the Bluetooth app
- A NIGHT/LOW mode that halves output for silent running
- Recovery charging from zero volts, and reconnecting to a lithium battery that has disconnected itself
It charges only. It won’t power 120V loads when you’re off shore power.
Option 2: MultiPlus-II 2x120V
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The Victron MultiPlus-II 2x120V replaces the converter and adds an inverter and transfer switch. Key datasheet points:
- 120/240V split-phase or 120V input
- 50A transfer switch, 50A per leg max AC input
- 12/3000 model: 2400W continuous at 25°C, 5500W peak, 120A charging
- PowerAssist on the L1 input, which helps on weak pedestals
- Output transfer under 18 ms on L1, about 40 ms on L2
In inverter mode, it ties L1 and L2 together at 120V. Victron points out that 240V loads only run on split-phase shore power, so large 240V loads don’t drain the battery.
Which One Fits?
| Goal | Pick |
|---|---|
| Better charging only | Blue Smart IP22 |
| 120V outlets off-grid | MultiPlus-II 2x120V |
| Weak campground power | MultiPlus-II (PowerAssist) |
Before You Wire
- Find what the old converter fed. Many RV converters sit inside the power center, so the DC panel may stay.
- Size DC cables and fuses for the new charger or inverter current.
- Set the charge profile for your battery in VictronConnect.
- Check the AC side. A MultiPlus-II goes between shore power and your AC panel, which is a code matter. Have an electrician do it.
- Remember the fridge, water heater and AC. Know which loads you’ll power from the inverter.
See the Blue Smart IP22 and the MultiPlus-II 2x120V.
Worked Example: Sizing a Blue Smart IP22 for a Weekend Rig
Say your motorhome has a 200Ah 12V LiFePO4 bank and you plug in at a campground after a weekend of dry camping that used about half of it.
- Energy to put back: 200Ah × 50% ≈ 100Ah.
- With a 12/30 IP22: 100Ah ÷ 30A ≈ 3.3 hours of bulk charging, plus a short absorption stage.
- With a 12/15 IP22: 100Ah ÷ 15A ≈ 6.7 hours, which still fits comfortably inside an overnight hookup.
Estimates: they ignore loads running at the same time and assume full rated current through most of the charge. If your fridge, fans and lights keep drawing 5 to 8A while you’re plugged in, that comes off the charger’s output, so a 30A model gives more breathing room for a larger bank.
Worked Example: Running the Coach on a MultiPlus-II
A typical evening in a 30-foot motorhome might look like this off shore power:
| Load | Watts (est.) | Hours | Wh (est.) |
|---|---|---|---|
| Microwave | 1,000W | 0.2 | 200 |
| TV and streaming box | 80W | 3 | 240 |
| Laptop charging | 60W | 2 | 120 |
| Coffee maker (morning) | 900W | 0.2 | 180 |
| Total | ≈ 740Wh |
Estimates based on common appliance ratings. Allowing roughly 10% for inverter losses, that’s about 815Wh, or around 68Ah from a 12V battery. A 200Ah lithium bank covers it with plenty left over for the DC fridge, water pump and lights. Every load in that list is well inside the 12/3000 model’s 2400W continuous rating, and even the microwave and coffee maker together sit under it.
Where the Old Converter Usually Lives
In many older motorhomes and travel trailers, the converter is built into a power center that also holds the 120V breakers and the 12V fuses. You have two common layouts to work with:
- Combined power center: the converter section can often be disabled or removed while the breaker and fuse panel stays in use. An IP22 then feeds the battery directly, and the DC fuse panel keeps working as before.
- Separate converter box: a standalone unit is the easiest swap. Its AC feed and DC output cables show you exactly where the new charger goes.
Either way, label every wire before you remove anything, and photograph the panel so you can check your work later.
Shore Power Basics for a MultiPlus-II Install
RV pedestals come in 30A 120V and 50A 120/240V versions. The MultiPlus-II 2x120V accepts both, because it can take a single 120V input or split-phase input. On a 30A pedestal, PowerAssist lets the battery top up the shore supply when a load briefly pushes past what the pedestal can deliver. You set the input current limit in VictronConnect or on a remote panel to match the pedestal, so the inverter adds battery power instead of tripping the campground breaker.
Adding Monitoring
Either upgrade path pairs well with a battery monitor such as a SmartShunt. It shows battery state of charge, current and time remaining in the VictronConnect app, which makes it easy to see how much of your bank a night of boondocking really uses. If you later add a GX device, the MultiPlus-II, solar charger and shunt all show up together on one screen and in VRM remote monitoring.
A Simple Upgrade Order
- Replace the converter with a lithium-ready charger, or install the MultiPlus-II.
- Add a battery monitor so you can see real usage.
- Add solar and an MPPT controller if you camp off-grid often.
- Add a DC-DC charger so the engine alternator charges the house bank while you drive.
Doing it in this order means every step is useful on its own, and you can stop at whichever point covers how you camp.
FAQ
Can I keep my RV’s distribution panel?
Often yes, but check how your converter is built in.
Will a MultiPlus-II run my 240V air conditioner on batteries?
No. In inverter mode, the output is 120V only.
Does the IP22 charge lithium?
Yes. Victron lists a Li-ion charge mode.
Is the IP22 waterproof?
No. IP22 means it’s protected against vertical dripping water, so mount it in a dry compartment such as the space the old converter used.
Can I set the MultiPlus-II input limit for a 30A pedestal?
Yes. The AC input current limit is adjustable, and with PowerAssist the battery helps cover short peaks above that limit.
Do I need a DC-DC charger as well?
It’s optional. A DC-DC charger lets the alternator charge the house battery while you drive, which suits travel days between campsites.
Sources: Blue Smart IP22 Charger 120VAC datasheet; MultiPlus-II 2x120V datasheet, victronenergy.com, accessed Oct 2026.
Related: EcoFlow Delta 3 Max RV Boondocking, EcoFlow Delta 3 Max Generator Charging, EcoFlow Delta 3 Max RV Air Conditioner, plus the Victron Energy Guide