Direct Answer
A converter turns 120V AC shore power or generator output into 12V DC to run your coach's house loads and charge the battery bank. An inverter does the opposite: it turns 12V DC battery power into 120V AC so you can run household appliances when no shore power is available. An inverter/charger combines both functions in one unit and adds a built-in transfer switch that automatically routes power between the two sources.
This page covers what each device does, how combined units work, what a transfer switch actually is, how installation complexity and cost differ between the three paths, and when upgrading from a standalone converter to an inverter/charger is worth the expense. It routes to linked detail pages for sizing guidance and product recommendations. If you need help sizing a converter for your battery bank, use the converter sizing calculator.
What a Converter Does
A converter is the device most factory RVs ship with. It sits inside a power center panel, takes 120V AC from the shore power cord or a generator, and outputs regulated 12V DC. That DC output goes two places simultaneously: it powers the 12V house circuits (interior lights, water pump, control boards, vent fans) and it flows into the battery bank as charge current.
The WFCO WF-8900-AD Power Center Series illustrates what a production converter looks like in practice. The product sheet for that series lists five output levels across the lineup: 35, 45, 55, 65, and 75 amps DC. The AC input range for all models is 105 to 130 V AC at 60 Hz. The WF-8955-AD, for example, outputs 55 amps DC from a 940-watt AC input. The series uses microprocessor-driven Auto-Detect technology that recognizes lithium-ion and lead-acid battery chemistry at startup and automatically selects the appropriate multi-stage charging profile, per WFCO's product sheet for the WF-8900-AD series verified 2026-09-23.
What a standalone converter does NOT do: it does not invert. When shore power drops, the converter stops. Your 120V AC outlets go dead. Only 12V loads continue running from the battery. A pure converter is a one-direction device.
For sizing guidance specific to your battery bank and house load, see what size RV converter do I need and the converter sizing calculator.
What an Inverter Does
An inverter takes 12V DC from the battery bank and converts it to 120V AC. That AC powers standard wall outlets when no shore power is connected. An inverter is what lets you run a laptop, a coffee maker, or a CPAP machine from stored battery power at a boondocking site.
The Renogy INVT-P2 series is a standalone pure sine wave inverter line. Per the Renogy INVT-P2 manual (verified 2026-09-23), the lineup spans 700W through 3000W continuous output. Surge ratings for each model are 2x continuous output for 1 second: the 1000W model surges to 2000W, and the 3000W model surges to 6000W. DC input is a 12V battery bank only, with an operating voltage range of 10 to 16V DC. Output is 115V AC at 60 Hz with less than 3% total harmonic distortion. The manual lists battery fuse recommendations by model: 100A for the 700W, 150A for the 1000W, 250A for the 2000W, and 400A for the 3000W.
The INVT-P2 manual explicitly states: "This is a non-charging inverter, requires a separate battery charging source." That is the key distinction. A standalone inverter draws from the battery but cannot replenish it. When shore power arrives, you need a separate converter or charger to recharge.
For sizing an inverter to your appliance loads, see what size inverter do I need.
What an Inverter/Charger Does
An inverter/charger combines three functions in one enclosure:
- Inverter: converts DC battery power to 120V AC for your outlets when off-grid
- Charger: converts 120V AC from shore power or a generator into DC to charge the battery bank (the "charger" half is what a standalone converter does)
- Transfer switch: automatically routes your AC outlets between the inverter output and incoming shore power, with no manual intervention
The transfer switch is what makes an inverter/charger different from simply owning both a standalone converter and a standalone inverter. Without a transfer switch, you would need to manually disconnect appliances from shore power before switching to inverter output, or wire a manual transfer switch into the system.
Xantrex Freedom XC: Transfer Switch in Detail
The Xantrex Freedom XC is an RV-targeted inverter/charger with a built-in transfer switch. The Freedom XC manual (document 975-0784-01-01 Rev E, verified 2026-09-23) documents two configurable transfer modes:
APL mode (appliance, the factory default): Transfer time from shore power to battery/inverter is less than 20 milliseconds. This is the recommended setting for most RV loads including anything with a motor, compressor, or heating element.
UPS mode: Transfer time is less than 10 milliseconds. The manual states explicitly: "Do not connect motor loads when in UPS transfer mode." Induction motors require 2 to 6 times running current at startup. The manual states the largest capacitor-start motor expected to run is 1/2 hp, and notes that connecting motor loads together with sensitive equipment in UPS mode risks damaging the transfer relay. UPS mode is intended only for sensitive digital equipment that requires near-instantaneous switchover.
The transfer relay in both Freedom XC models (1000 and 2000) is rated at 30A, with a 24A continuous rating. The transfer relay is rated for 2 hp motor loads per the specification table in the manual.
The Freedom XC 2000 charger output is user-selectable from 5 to 80A DC in 5A increments. The preset LFP absorption voltage is 14.4V and float voltage is 13.6V per Table 11 and Table 12 in the manual. DC wiring requirements: No. 2/0 AWG minimum for cable runs under 5 feet (1.5 m), with a maximum battery fuse size of 250A DC. DC cables must be stranded copper rated 90 degrees C minimum.
The Freedom XC inverter output (2000W model) is 2000W continuous at 40 degrees C and true sine wave. DC input for inverting draws up to 192A at full load, with current surges up to 400A when starting heavy loads.
Victron MultiPlus 12/3000/120: Higher-Power Example
The Victron MultiPlus 12/3000/120 represents a higher-capacity inverter/charger. Per the Victron manual (verified 2026-09-23):
Continuous inverter output: 3000 VA / 2400W at 25 degrees C, derated to 2200W at 40 degrees C and 1700W at 65 degrees C. Peak power: 6000W. Maximum efficiency: 93%.
Charger output: 120A DC charge current for the house battery at 25 degrees C ambient. Absorption voltage: 14.4V DC (default, adjustable). Float voltage: 13.8V DC.
DC wiring for cable runs of 0 to 5 meters: 2x 50mm2 (two positive and two negative conductors). Recommended DC fuse: 400A. The maximum transfer (feed-through) current is 50A, and the AC input must be protected by a fuse or circuit breaker rated at 50A or less.
The MultiPlus includes PowerAssist, which can supplement shore power current during peak demand: with a 50A shore input limit, PowerAssist can add up to 25A from the inverter, allowing up to 75A of AC output briefly. The AC out-1 circuit breaker or fuse should be rated no higher than 75A to account for this.
For lithium battery compatibility: the MultiPlus supports LiFePO4 via its BMS connection interface and adjustable charge voltages. Verify with your battery manufacturer that the charge voltage profile the MultiPlus is set to matches their documented requirements for your exact model.
The Three Paths: Comparison Table
| Feature | Standalone Converter | Standalone Inverter | Inverter/Charger |
|---|---|---|---|
| Converts AC to DC (charges battery) | Yes | No | Yes |
| Converts DC to AC (powers outlets off-grid) | No | Yes | Yes |
| Built-in transfer switch | No | No | Yes |
| Manual switching needed | n/a | Yes (or add transfer switch) | No, automatic |
| Single DC wiring run | Yes | Yes | Yes (shared) |
| Box count | 1 | 1 | 1 (replaces both) |
| Typical install complexity | Low | Moderate | Moderate to high |
| Typical cost range | Lower | Moderate | Higher |
| Works without shore power | No (only charges on shore) | Yes | Yes |
| Charges battery on shore power | Yes | No | Yes |
Install Complexity and Cost
Standalone converter: Most factory coaches already have one in the power distribution center. Replacing it requires matching output amperage and physical form factor. No inverter wiring, no transfer switch wiring.
Adding a standalone inverter to an existing converter: Requires its own DC cable run from the battery (sized to the inverter's current draw), its own DC fuse close to the battery, a mounting location in a ventilated space not directly above the battery, and a decision about which AC outlets the inverter feeds. Without a transfer switch, you either run a dedicated inverter-only outlet, or you wire in a separate transfer switch. The Renogy INVT-P2 manual states the inverter must not share an outlet with a source also fed from utility power or a generator, meaning a transfer switch is a practical necessity if you want the inverter to feed the same outlets as shore power.
Inverter/charger replacing both: The DC wiring is typically heavier gauge than a standalone converter because the inverter draw is much higher. For the Victron MultiPlus 12/3000/120 the minimum is 2x 50mm2 for runs up to 5 meters. The Freedom XC 2000 requires No. 2/0 AWG minimum for runs under 5 feet. The trade-off is that you make one heavy DC wiring run instead of two separate runs (one for the converter, one for the inverter), and the transfer switch is internal, simplifying the AC panel wiring.
Installation by a qualified technician is common practice for inverter/charger installs. The Freedom XC manual references NEC wiring standards. The Renogy INVT-P2 manual requires installation by a qualified technician per local and national electric codes. These are editorial observations about common RV practice, not a code requirement that applies universally, but they reflect the complexity of the DC wiring involved.
When the Upgrade Is Justified
A standalone converter is adequate when:
- You primarily camp at sites with shore power
- You have no 120V appliances you need to run off-grid
- Your battery bank is used mainly as a buffer for 12V house loads
- Budget is a constraint and you do not have plans for boondocking
Adding a standalone inverter makes sense when:
- You want off-grid 120V capability on a budget
- You can live with a dedicated inverter-only outlet or are willing to add a manual transfer switch
- You already have a working converter you do not want to replace
- Your 120V off-grid draw is modest (laptop, phone charging, small appliances)
Upgrading to an inverter/charger makes sense when:
- You want seamless, automatic switching between shore power and battery-backed 120V
- You plan to replace an aging or under-sized converter anyway
- You are installing a larger lithium battery bank and want to take full advantage of fast charge rates
- You want to eliminate the manual transfer switch from the system
- You are doing a full electrical rebuild and want the cleanest possible wiring
For lithium battery banks specifically: if you are upgrading to LiFePO4 and want your converter or inverter/charger to deliver the correct charge profile automatically, check whether the unit you are considering supports the lithium profile for your exact battery model. The WFCO WF-8900-AD series auto-detects chemistry and adjusts the profile. The Freedom XC has a selectable LFP preset. Verify the charge voltage settings in your unit match your battery manufacturer's published requirements. For more on selecting a lithium-compatible converter, see best RV converter for lithium batteries.
Frequently Asked Questions
Does every RV have a converter?
Virtually every factory-built RV shipped with shore power capability includes a converter or power center. It is the device that prevents your 12V house circuits from draining the battery when plugged in, and it allows the battery to charge from shore power. If you have a power distribution panel inside the coach, the converter is almost certainly integrated into it.
If I have an inverter/charger, do I still need a separate converter?
No. The charger half of an inverter/charger performs the same AC-to-DC conversion function as a standalone converter. You replace the converter with the inverter/charger; you do not run both.
What happens to my 12V house loads when I switch from shore power to inverter?
In an inverter/charger system with a built-in transfer switch (like the Freedom XC), 12V house loads continue uninterrupted because they are powered directly from the battery regardless of which source is feeding the 120V side. The transfer switch governs only the 120V AC outlets. Your lights, water pump, and vent fans keep running.
What does the transfer switch transfer time actually matter for?
For most loads, 20 milliseconds is imperceptible. A desktop computer or a sensitive audio device may glitch on a 20ms gap; a microwave, a coffee maker, or a fan will not notice it at all. The Xantrex Freedom XC UPS mode cuts transfer to under 10ms for sensitive electronics, but that mode must not be used with motor loads because of the relay stress on startup surge current.
Can I use any inverter with my existing converter?
A standalone inverter can coexist with an existing converter as long as the AC wiring is arranged so that the inverter output does not feed the same outlets simultaneously with shore power. This requires either dedicated inverter-only outlets or a transfer switch. The Renogy INVT-P2 manual states explicitly that the unit must not be connected to an electrical panel also fed from utility power or a generator without proper transfer switching in place.
Is a larger inverter/charger always better?
Not necessarily. A larger unit means heavier DC cabling, a larger DC fuse, and more inrush current demand from the battery bank. The Victron MultiPlus 12/3000/120 requires a 400A fuse and 2x 50mm2 cable. That is a significant wiring project. Match the unit's continuous output to your realistic peak 120V load, not to a theoretical maximum. Oversizing creates wiring complexity without adding usable capacity in most RV applications.
Sources
- WFCO WF-8900-AD Power Center Series Product Sheet WFCO manufacturer product sheet for the WF-8900-AD series (2024 edition). Proves: model lineup (WF-8935-AD through WF-8975-AD), DC output ratings (35 to 75 amps DC per model), AC input range (105 to 130V AC, 60 Hz), Auto-Detect microprocessor technology recognizes lithium-ion and lead-acid chemistry and adjusts charging profile automatically, multi-stage charging in both profiles, eleven DC circuits including two 30A DC circuits. Verified live 2026-09-23 via browser (manufacturer PDF; scripted fetches return 403, browser fetch confirmed content). Authority tier: manufacturer product sheet.
- Xantrex Freedom XC Inverter/Charger Owner's Manual (975-0784-01-01 Rev E) Xantrex manufacturer manual for the Freedom XC 1000 and Freedom XC 2000 (12V) inverter/chargers. Proves: APL transfer mode less than 20ms, UPS transfer mode less than 10ms, motor load prohibition in UPS mode, transfer relay rated 30A / 24A continuous, transfer relay rated for 2 hp motor loads, largest capacitor-start motor expected 1/2 hp, DC wiring requirements (No. 2 AWG for XC 1000 and No. 2/0 AWG for XC 2000 under 5 feet one-way), maximum battery fuse (150A for XC 1000, 250A for XC 2000), DC charger output selectable 5 to 80A (XC 2000), LFP absorption preset 14.4V and float preset 13.6V, inverter continuous output 1000W and 2000W at 40 degrees C, full-load DC current 100A and 192A, current surges to 400A on heavy loads, AC input branch breaker rated no more than 30A. Verified live 2026-09-23 via PDF fetch. Authority tier: manufacturer manual.
- Victron MultiPlus 12/3000/120 Manual (firmware xxxx4xx) Victron Energy manufacturer manual for the MultiPlus 12/3000/120. Proves: recommended DC fuse 400A, DC cable sizing 2x 50mm2 for 0 to 5 meter runs (two positive and two negative conductors), charge current 120A DC at 25 degrees C, absorption voltage 14.4V, float voltage 13.8V, inverter continuous output 3000 VA / 2400W at 25 degrees C (2200W at 40 degrees C, 1700W at 65 degrees C), peak power 6000W, maximum efficiency 93%, maximum feed-through (transfer) current 50A, AC input protected by fuse or breaker rated 50A or less, PowerAssist can add up to 25A supplemental during peak, AC out-1 breaker/fuse rated no higher than 75A when PowerAssist active. Verified live 2026-09-23 via PDF fetch. Authority tier: manufacturer manual.
- Renogy INVT-P2 Pure Sine Wave Inverter Manual Renogy manufacturer manual for the INVT-P2 series standalone inverters (700W, 1000W, 2000W, 3000W). Proves: model lineup and continuous wattage ratings, surge ratings (2x continuous for 1 second: 700W surges to 1400W, 1000W to 2000W, 2000W to 4000W, 3000W to 6000W), DC input 12V only with operating range 10 to 16V, output 115V AC at 60 Hz, THD less than 3%, battery fuse recommendations (100A for 700W, 150A for 1000W, 250A for 2000W, 400A for 3000W), explicit statement that unit is non-charging and requires separate battery charging source, prohibition against connecting AC output directly to a panel also fed from utility power or generator, installation by qualified technician required per NEC. UL certified to 458 and ETL listed to CSA 22.2 No. 107.1-01. Verified live 2026-09-23 via PDF fetch. Authority tier: manufacturer manual.
Published 2026-09-23. Electrical specifications are model-specific: confirm every figure against the manual for your exact equipment before acting on it.