What do I need to change when converting an RV to lithium batteries?

You must update your charging sources to use LiFePO4 voltage profiles: replace or reconfigure the shore power converter/charger, update MPPT solar controller settings, and add or upgrade the DC-DC charger. You should also add a battery monitor (voltage-based gauges are inaccurate for LiFePO4). The battery swap itself is often straightforward — same terminal layout, same voltage — but the charging equipment must match.

Can I just swap AGM for LiFePO4 without changing anything else?

The battery will charge and work, but not optimally. The main risk: if your shore power converter has an equalization mode (many do), it will eventually run an equalization cycle at 15–16V that damages LiFePO4 cells. Disable or replace the converter. MPPT solar controllers with an AGM profile are usually fine (the voltage overlap is close enough), but setting them to LiFePO4 profile or 14.4V absorption is better.

Converting an RV From Lead-Acid to Lithium Batteries

Converting an RV from lead-acid to lithium is one of the highest-value upgrades you can make — more usable capacity, lighter weight, and no maintenance. Here's how to do it correctly.

Before you buy, run your appliances through our free battery and electrical calculator to see how much capacity your trips actually need.

What changes vs what stays the same

Stays the same:

Battery voltage (12V stays 12V)
Wiring (same terminals, same connections)
Inverter (sees the same 12V)
12V loads (fridge, lights, water pump — all unchanged)
Battery compartment (most 100Ah LiFePO4 batteries fit Group 27 or 31 spaces)

Must change or reconfigure:

Shore power converter/charger (needs LiFePO4 profile, no equalization)
MPPT solar controller settings (set to LiFePO4 or 14.4V absorption)
Battery monitor (replace voltage gauge with shunt-based coulomb counter)

Should remove:

Battery venting (LiFePO4 doesn't produce hydrogen — but leave the vent intact if the compartment is also open to the outside, as it does no harm)

A blue CATL prismatic lithium iron phosphate cell with two terminals — A prismatic LiFePO4 cell is a component of a battery, rather than a complete protected drop-in RV battery. Photo: Aeroid. CC BY-SA 4.0. Resized for this page.

The site owner’s battery bay, inverter and electrical equipment inside a Fiat Ducato conversion — Battery and inverter access in the owner’s UK build, shown for layout context rather than as a US wiring reference. Photo: Roam Wired.

A CTEK DC-DC charger beside an auxiliary AGM battery and portable fridge — A real auxiliary AGM-battery and CTEK charger setup. It illustrates the charging path rather than the specification of a current lithium kit. Photo: Stephan Ridgway from Brisbane, Australia. CC BY 2.0. Resized for this page.

Step-by-step conversion

1. Check your converter/charger

This is the most critical step. Open the manual for your RV's shore power converter (Parallax, Progressive Dynamics, Magnetek, etc.) and look for:

Equalization mode: Does it run periodic 15–16V equalization? This will damage LiFePO4. Disable it or replace the converter.
LiFePO4 mode: Newer Progressive Dynamics PD9100 series and some others have a LiFePO4 setting.

If your converter has no LiFePO4 mode and has equalization: Replace with a Victron Blue Smart IP22 ($80–$120) or a Progressive Dynamics PD9130LV with lithium mode.

2. Update solar controller settings

In your MPPT controller app or settings:

Change battery type to LiFePO4, or
Set manually: absorption 14.4V, float 13.5V (or disable float), equalization OFF

3. Remove old batteries

Note the state of charge and voltage for reference. Disconnect negative first, then positive. Disconnect from any series/parallel connections if multiple batteries.

4. Install LiFePO4 batteries

Drop-in LiFePO4 in the same group size connects the same way — positive to positive bus, negative to negative/shunt. Connect negative first, then positive (opposite of disconnect order). Or follow your van's specific wiring.

5. Add battery monitor

Replace any voltage-based "fuel gauge" with a Victron SmartShunt. Connect the shunt to the battery negative cable and ensure all loads and charging sources connect through the bus bar (not directly to battery negative).

6. Configure and test

Charge the battery fully from shore power with the updated converter settings. Verify:

Voltage reaches 14.2–14.4V during absorption
Current tapers to near zero when full
No equalization voltage spike
Battery monitor shows accurate SoC% after calibration

Two red insulated wires terminated with crimped ring lugs — Ring lugs on stranded wire. Match the conductor size, stud size and crimp tooling to the terminal. Photo: Hundehalter. CC BY-SA 3.0. Resized for this page.

Yellow digital multimeter with red and black test leads — A multimeter helps verify a circuit; conductor colour or a product label alone is not a measurement. Photo: Ahnaf Piash. Pexels License. Resized for this page.

Common mistake: forgetting the generator

If your RV has a built-in generator charging the house battery through the converter, the same converter LiFePO4 upgrade applies. The generator-powered converter is the same unit as the shore power converter in most RVs.