If your existing converter charges your batteries properly, buy a plain inverter. If the converter needs replacing anyway — which a lithium upgrade almost always forces — buy an inverter/charger and let one box do both jobs. That single question settles this choice for most rigs, because an inverter/charger is not a better inverter: it is an inverter, a converter and an automatic transfer switch sharing a case, and its price only makes sense when you needed at least two of the three.
The difference at a glance
| What it handles | Plain inverter | Inverter/charger |
|---|---|---|
| Makes 120V from the battery bank | Yes | Yes |
| Charges the bank on shore power | No | Yes — 80A (Xantrex) to 120A (Victron) |
| Replaces the factory converter | No | Yes |
| Passes shore power through to loads | No | Yes |
| Automatic shore ↔ battery switchover | No | Yes — under 20ms on the Xantrex |
| Boosts a weak pedestal | No | PowerAssist, on the Victron only |
| Lithium charge profile | Not its job | Built in on both units here |
| Install | Added alongside what you own | Replaces the converter — a rewiring job |
| Typical price | Low to mid | Two to five times a plain inverter |
Three jobs, one or three boxes
Follow the energy to the selected 120V loads. The diagrams compare a separate converter, inverter and source switch with an inverter/charger that combines those functions.
AC energy DC energy Inactive path
Shore power available
Shore AC supplies the selected loads and the charger replenishes the battery.
Separate equipment
A plain inverter needs separate source selection for shared loads. Keep the converter on a shore-only supply.
Integrated inverter/charger
Dashed boundary = one case. The unit coordinates charging, inversion and transfer.
Running from the battery
The inverter supplies the selected AC loads. The shore-fed charger is inactive.
Separate equipment
A plain inverter needs separate source selection for shared loads. Keep the converter on a shore-only supply.
Integrated inverter/charger
Dashed boundary = one case. The unit coordinates charging, inversion and transfer.
Avoid the battery-to-itself loop
Conversion losses drain the bank. The inverter must not power the converter that is trying to recharge that same bank.
Energy-flow overview, not a wiring diagram. Each drawing shows one 120V path and selected loads; protection, bonding and other charging sources are omitted. A 50A transfer rating on the original 120V MultiPlus does not provide both legs of a 50A RV service. PowerAssist is an additional supported mode, not shown in these two basic states.
Sources: Victron MultiPlus manual, §§2.1 and 4.3; Xantrex Freedom XC guide, AC distribution and operating modes; Renogy P2.
Every powered RV does three things with electricity: it converts shore power to 12V to run the DC systems and charge the batteries (the converter), it may invert battery power to 120V when unplugged (the inverter), and something has to switch loads between those sources (a transfer switch, or you, walking to the compartment).
A factory rig ships with the first job done. Buying a plain inverter adds the second; shared loads need manual selection or a suitable separate transfer switch. An inverter/charger does all three — which is why the honest comparison is never “inverter vs inverter/charger” on price alone, but inverter you are buying plus converter you already own plus switching you can live with, against one box that does the lot.
The converter question decides it
Here is why this choice keeps coming up in lithium upgrades: most factory converters hold a lead-acid float voltage around 13.6V, and LiFePO4 wants 14.2–14.6V of absorption to actually finish charging. Dakota Lithium states the consequence plainly — a lead-acid charger fills a lithium battery to about 80%, forever. We cover which converters fix that in the best RV converter for lithium batteries.
So the fork looks like this:
- Converter already lithium-capable (or you run lead-acid it charges fine): the charging job is done. Buy the inverter alone, spend the difference on the bank, and skip the rewiring.
- Converter needs replacing: you are about to buy a converter and an inverter and probably wish for automatic switchover. That is the inverter/charger’s case made for it — one purchase, one install, one set of battery cables, and the transfer switch arrives free.
The parts math, honestly run
Price the plain path completely before calling it cheaper: the inverter, plus a lithium-capable converter if yours is not, plus heavy cable runs for each box, plus a transfer switch if you want any outlets to move between sources on their own. Run that way, the gap narrows — and on a rig that needed the converter anyway, it often inverts.
It does not always. A healthy converter and modest inverter needs keep the plain path solidly cheaper, which is why the Renogy 2000W with its included cables remains the default answer for rigs whose charging already works. Both units here are true sine, so the waveform question does not separate them.
Match the relay to the rig
Pass-through is the shore-current rating of the path through the unit. Match it to the circuits and protection in the design. It does not tell you how many legs the unit handles or how much battery-powered output it can make:
- 30A rig: the Xantrex Freedom XC 2000’s 30A relay is sized to the service exactly, and its charger dials from 80A down to 5A, which is how you refill a big bank from a small pedestal without tripping it.
- 50A coach: there are two 120V legs to account for. The original MultiPlus 12/3000/120-50 120V handles one 120V path. It can serve selected circuits, but its 50A relay does not by itself pass both legs of the coach. A whole-coach system needs equipment and a design that handle both legs; the MultiPlus-II 2x120V is a different model with that architecture. PowerAssist can supplement a limited shore feed on supported units, including on a 30A supply, within the configured input and output limits.
The equipment comparison is in Victron vs Renogy; the two supply legs are explained in 30 amp vs 50 amp RV.
Either way, the charger stage becomes a large new load on the pedestal while it works — an 80A charge into a 12V bank is roughly 1,200W of shore draw before anything else in the rig turns on.
The case for staying separate
A comparison that always lands on the expensive box is an advertisement, so here is the other side.
One box is one point of failure for three functions. When a plain inverter dies, your converter still charges and your shore power still works. When an inverter/charger dies, the compartment wall is doing nothing until the replacement arrives — and both units we recommend are dealer-network products, not next-day marketplace orders.
The plain path installs in an afternoon. An inverter/charger replaces the converter, which means AC-in, AC-out and DC wiring all get touched. It is a rewiring project, frequently a professional one.
Idle draw is on the batteries either way. The MultiPlus’s 20W zero-load (8W in search mode) is well documented; the Xantrex’s is unpublished, which we flagged in the roundup. A plain inverter you switch off at the remote costs nothing while off — and the converter it left in place draws nothing from the bank at all.
Charging while driving is neither box’s job. The alternator side of the system is a DC-DC charger, whichever way this decision goes.
Work down this list
Stop at the first line that describes your rig.
-
Your converter charges your battery chemistry properly, and you want 120V off-grid
Plain inverter
The charging job is already done. Add the inverter, keep its circuit clear of the converter, and spend the difference on battery.
-
You are upgrading to lithium and the converter is one of the things that has to change
Inverter/charger
You were buying two of its three functions anyway. One box, one install, and the transfer switch comes free.
-
30A rig, converter being replaced
Xantrex Freedom XC 2000
The 30A relay matches the service, the 5–80A charger works from small pedestals, and the warranty transfers with the RV.
-
Large bank or power-system rebuild, with charging and PowerAssist wanted
Consider a Victron system sized to the actual circuits
The original 120V MultiPlus serves one AC path. A 50A coach needs both legs accounted for; choose the model and architecture before the installation.
-
The budget is genuinely fixed
Plain inverter now, converter later
A plain inverter plus a lithium-capable converter bought separately can undercut the combined box — price all the parts before deciding.
The picks
Inverter/charger for 30A rigs
Xantrex Freedom XC 2000
A 30A transfer relay sized to 30A service, an 80A lithium-profile charger, and a warranty that transfers with the RV.
Inverter/charger for larger 120V load groups
Victron MultiPlus 12/3000
The 120A charger and PowerAssist make a weak pedestal behave like a strong one.
The plain-inverter path
Renogy 2000W P2
If your converter already charges your chemistry properly, this plus what you own does the whole job.
Both inverter/chargers, the plain-inverter alternatives, and everything we verified about each are in the best RV inverters.
Related guides
- Best RV inverters — all seven units compared, both categories included.
- Best RV converter for lithium batteries — the plain path’s other half, if your converter is the problem.
- What size inverter do I need? — the wattage decision, sized from the battery bank.
- Do you need a pure sine wave inverter? — the waveform half of the shopping question.
- Do I need a DC-DC charger? — charging from the alternator is a third box, whichever way this goes.
- 30 amp vs 50 amp RV — what the pedestal can give while a big charger is working.
- The electrical section collects everything published so far.
For how products on this site are selected and what we do not claim about them, see the editorial policy.
Questions worth answering
Does an inverter/charger replace my RV's converter?
Yes — that is most of the point. The converter/charger stage inside it does the same job as the factory converter, usually with more output and a proper lithium profile, so the old converter is disconnected or removed rather than run alongside. One box, one set of battery cables, one thing on the wall of the compartment.
Can I keep my converter and just add a plain inverter?
Yes, and if the converter already charges your battery chemistry properly this is the cheaper, simpler path — the standard one. The one rule: the circuit feeding the converter must never be powered by the inverter, or the converter will try to charge the battery from the battery. Keep the converter's breaker out of anything the inverter feeds.
What happens to my outlets when shore power drops?
With an inverter/charger, the transfer relay switches the loads it feeds onto battery in tens of milliseconds — Xantrex publishes under 20ms for the Freedom XC, and 10ms in its UPS mode, fast enough that most electronics never notice. A plain inverter needs suitable separate switching to transfer shared loads automatically. Without it, only the loads already supplied by the inverter remain on battery power.
Can an inverter/charger charge the batteries while inverting?
No — the two modes are either/or by design. On shore power it passes the pedestal through to your loads and charges the bank; off shore power it inverts. What the Victron MultiPlus adds is the blend in between: PowerAssist supplements a weak shore feed with inverter output during peaks, then goes back to charging when the load drops.
Is a 30A transfer relay a problem on a 50A coach?
It limits the 120V path through that unit to 30A, but can still serve a properly designed group of selected circuits in a 50A coach. A 50A RV has two 120V legs. The original 120V MultiPlus's 50A relay is a single-phase path, not a complete two-leg solution. Choose the architecture and protected circuits as well as the relay rating.