Buying guide · 11 min read · Updated October 1, 2026

6 Best RV Converters for Lithium Batteries in 2026: A Practical RV Guide

Six standalone RV converters for lithium batteries in small rigs, compared on 35 to 75 amp sizing, adjustable output, auto-detect, and install effort.

By Bowen HigginsRV Editor at RV Gear Lab6 products comparedSpec-sheet researched

Small trailers, teardrops, truck campers, and van builds rarely need the 55 to 100 amp converters sold for big fifth wheels. A 35 or 45 amp unit is often enough to run the lights and fan while topping up a single lithium battery, and it is gentler on a battery whose BMS limits charge current. What matters more at this size is getting the lithium voltage right.

For this roundup we looked at standalone converters you can mount on their own, separate from a power center. We compared how each sets a lithium charge, whether by adjustable output, a dedicated mode, or automatic detection, plus the amp size, protections, and how much rewiring the install takes. One larger 75 amp unit is included for owners who need headroom.

RV Gear Lab field notes

The Rig Fit Check

Start with the job: PowerMax PM4 45A RV Converter with 3-Stage Charger, Lithium Compatible leads this shortlist for small trailers and vans with one or two lithium batteries. Use that fit as a reference point, then compare the alternatives against your own space and workload.
Specs that separate the picks: The first details to compare are 45A, adjustable 13V to 16.5V, 35A, auto lead/LiFePO4, 45A regulated output. Confirm the exact model and included components before ordering.
Trade-off to plan for: Upper adjustment range can overcharge if misset

Before you buy

What Matters Before You Choose an RV Converter for Lithium Batteries

Key buying criteria so you get the right fit the first time.

01
Amp rating matched to the battery
A converter's amp rating is the most current it can deliver to loads and battery together. Small lithium batteries often accept only 20 to 50 amps of charge, so a huge converter brings no benefit and can trip the BMS. Compare the converter rating with the max charge current on your battery spec sheet before choosing a size.
02
How the lithium voltage is set
Lithium charging depends on reaching about 14.2 to 14.6V. Some units adjust by dial, some have a dedicated LiFePO4 mode, and some detect the battery automatically, each with a different chance of user error. Read how the listing says lithium is selected, and avoid units that only say compatible without a mechanism.
03
Fixed and maximum voltage limits
Several units can output up to 16.5V for special uses. That is well above a 12V LiFePO4 battery's safe range, and an accidental setting can trigger BMS shutdown. Note the maximum voltage in the listing and plan to verify your setting with a multimeter.
04
Standalone wiring needs
A standalone converter needs its own AC feed, DC cables to the battery or fuse panel, and correct fusing. In a van build that is easy to plan; in a trailer it may mean running new cable. Check the manual for cable gauge and fuse size, and add those parts to your budget.
05
Shore power tolerance
Low campground voltage can reduce some converters' output, slowing charging. A published minimum input voltage at full output shows the unit was designed for weak pedestals. Look for a number like the WFCO's 100V rating instead of a broad input range alone.
06
Protection and certification
Reverse polarity, overload, and thermal protection guard against wiring mistakes and hot compartments. A UL or CSA listing adds independent safety review. Check the listing for named protections and an explicit certification mark.

Our standards

Why You Can Trust RV Gear Lab

At RV Gear Lab, we compare products based on rig fit and power or hookup compatibility, verified specifications, usability, setup requirements, weight, durability, and real-world trade-offs. We do not rank products purely on marketing claims or commission rates.

We have not personally tested every product listed. Where hands-on testing is not available, recommendations are based on verified manufacturer specifications, product documentation, use-case fit, and comparative research.

How we review RV gear →

Detailed reviews

The 6 best rv converters for lithium batteries, explained

Best Overall · 1 of 6

PowerMax PM4 45A RV Converter with 3-Stage Charger, Lithium Compatible

45A, adjustable 13V to 16.5V
3-stage, LiFePO4 compatible
No-rewire install

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Best for: Small trailers and vans with one or two lithium batteries

Our take

Pick this for a teardrop, van, or small trailer with one or two lithium batteries.

Why it made the shortlist

The PowerMax PM4 45A leads this guide because it gives small-rig owners precise lithium control at a fair price. Its output adjusts from 13V to 16.5V DC so you can set it to your battery maker's charge voltage, and its 3-stage routine of bulk, absorption, and float covers AGM, gel, flooded, and LiFePO4.

Compared with the WFCO WF-9835-AD-CB ranked second, it trades automatic detection and UL listing for adjustability and about $64 in savings. It also outclasses the PM3-45-SME below on documentation, with protections for reverse polarity, overload, and thermal shutdown spelled out, and PowerMax says the install takes under 10 minutes without rewiring.

What works

Output adjusts to match your lithium charge voltage
3-stage bulk, absorption, float charging
Reverse polarity and thermal shutdown protection
Installs in about 10 minutes per PowerMax

Watch out for

Upper adjustment range can overcharge if misset
No UL listing documented

Check price on Amazon

Best Auto-Detect · 2 of 6

WFCO WF-9835-AD-CB 35A Deck-Mount Converter Charger, Auto-Detect

35A, auto lead/LiFePO4
Full output down to 100V
UL/CSA listed

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Best for: Owners who want certified, hands-off lithium charging

Our take

This suits a small trailer owner who wants set-and-forget lithium charging from an OEM brand.

Why it made the shortlist

The WFCO WF-9835-AD-CB brings the brand's patented Auto-Detect to a 35 amp size. It recognizes lead-acid or LiFePO4 and adjusts its multi-stage charging on its own, keeps full output down to 100 volts of shore input, and is UL/CSA listed and FCC compliant.

In exchange you get third-party safety certification and nothing to adjust.

What works

Auto-Detect handles lithium with no settings
Full output even at 100V shore input
UL/CSA listed and FCC compliant

Watch out for

Most expensive per amp in this list
35A charges slower under heavy loads

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Best Adjustable Alternative · 3 of 6

PowerMax PM3-45-SME 45A Converter Charger, Adjustable Lithium

45A regulated output
Adjustable lithium output
Standalone deck mount

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Best for: Owners who want a PowerMax PM3 series unit

Our take

The strongest case for PowerMax PM3-45-SME 45A Converter Charger, Adjustable Lithium is adjustable output for lithium setups.

Why it made the shortlist

The PowerMax PM3-45-SME is a 45 amp standalone deck-mount converter whose adjustable output supports properly configured lithium charging, with multi-stage charging for lead-acid and current limiting, reverse-polarity, and thermal safeguards.

It ranks below the PM4 45A because PowerMax documents it less fully and it costs about $20 more.

What works

Adjustable output for lithium setups
45A suits single-battery small rigs
Thermal and reverse-polarity protection

Watch out for

Adjustment range not listed

Check price on Amazon

Best 4-Stage Pick · 4 of 6

RecPro 45A RV Power Converter and Battery Charger

45A, 4-stage charging
Lead and lithium compatible
Sold in 35A to 100A

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Best for: Owners loyal to an RV parts brand

Our take

This suits owners who want an RV brand with the option to buy the same line in 35 to 100 amps later.

Why it made the shortlist

The RecPro 45 amp converter is a straightforward 120VAC to 12VDC unit with 4-stage charging that RecPro lists for both lead and lithium batteries, and it powers 12V lights and appliances while it charges.

What works

4-stage charging for long storage periods
Runs 12V loads while charging the battery
Same line available in larger sizes

Watch out for

Lithium voltage not published
Pricier than the VEVOR with fewer details

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Best Budget · 5 of 6

VEVOR 45A RV Power Converter Battery Charger

45A, LiFePO4 mode
Fixed 13.0V, 14.6V, 16.5V
Six listed protections

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Best for: Teardrops and vans with a small lithium battery

Our take

Pick it for a tight budget or a small lithium battery.

Why it made the shortlist

The VEVOR 45 amp converter is the cheapest way into proper lithium charging here at about $63. It offers dedicated lead-acid and LiFePO4 modes, a fixed voltage mode at 13.0V, 14.6V, or 16.5V, six listed protections, and an included copper cable.

VEVOR itself sizes it for small 30 to 50Ah batteries, which makes it a good fit for teardrops and van builds.

What works

Dedicated LiFePO4 charging mode
Copper cable included in the box

Watch out for

16.5V fixed mode is unsafe for 12V lithium
Sized by VEVOR for small 30 to 50Ah batteries

The catch: It costs less than half the PowerMax PM4 45A ranked first while matching its 45 amps, but VEVOR gives fewer staging details and no UL listing.

Check price on Amazon

Best for More Headroom · 6 of 6

PowerMax PM3-75LK 75 Amp Converter, Lithium Compatible

75A rated, lithium compatible
3-stage smart charging
Series or parallel capable

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Best for: Owners with two or more lithium batteries

Our take

Choose it if you run two or more lithium batteries and want faster recharge.

Why it made the shortlist

The PowerMax PM3-75LK is in this guide for owners who outgrow 45 amps. It is listed as a 75 amp lithium compatible converter with 3-stage smart charging and adjustable power supply modes, and PM3 units can be wired in series or parallel for even more output.

It has the most current of any pick here for about $129, less than the 45A PowerMax PM4, which makes it the best value per amp. It ranks last for this small-rig guide because 75 amps exceeds what a single 100Ah lithium battery usually accepts, and the listing text is inconsistent, mentioning a 55 amp output in one bullet.

What works

Most amps per dollar in this list
3-stage charging protects battery life
PM3 units can be paralleled for more output

Watch out for

Too much current for one 100Ah battery

Check price on Amazon

Methodology

How We Built This Shortlist

Each pick was assessed across 5 criteria weighted for real-world use.

Lithium voltage control

We compared how each unit reaches a lithium charge voltage: adjustable output, a dedicated LiFePO4 mode, or auto-detect.

Right-sizing for small rigs

Amp ratings from 35 to 75 were matched to typical single and dual battery setups and common BMS charge limits.

Standalone install effort

We weighed mounting, rewiring, and cable needs, since these units install outside a power center.

Documented protections and listing

Reverse polarity, thermal, and overload protection, plus any UL or CSA listing, counted toward each score.

Cost per amp

Price was compared against output current and the depth of each listing's technical detail.

Decision guide

Match an RV Converter for Lithium Batteries to Your RV

By Battery Setup

Your setup	Recommended pick	Why
One 50Ah battery in a teardrop	VEVOR 45A	VEVOR sizes it for 30 to 50Ah
One 100Ah battery	PowerMax PM4 45A	45A with adjustable lithium voltage
One 100Ah, hands-off owner	WFCO WF-9835-AD-CB	Auto-Detect and UL listing
Two or more 100Ah batteries	PowerMax PM3-75LK	75A shortens recharge time

By Budget

Budget	Recommended pick
Under $70	VEVOR 45A
About $125 to $130	PowerMax PM4 45A or PowerMax PM3-75LK
About $140 to $150	RecPro 45A or PowerMax PM3-45-SME
About $190	WFCO WF-9835-AD-CB

Adjustable Output vs Auto-Detect

Adjustable output

You dial in the exact voltage your battery maker specifies, which gives precision but needs a meter and care. The PowerMax PM4 45A, PowerMax PM3-45-SME, and PowerMax PM3-75LK use this approach.

Auto-Detect

The converter identifies lead-acid or LiFePO4 and selects the profile itself, so there is nothing to set. In this comparison that is the WFCO WF-9835-AD-CB.

Choose Auto-Detect if you want zero setup; choose adjustable if your battery has a specific charge voltage.

By Install Situation

Situation	Recommended pick
Van build with custom wiring	PowerMax PM4 45A
Replacing a dead factory converter quickly	WFCO WF-9835-AD-CB
Mounting near the battery in a cargo trailer	PowerMax PM3-45-SME
Adding a second charger alongside solar	VEVOR 45A

For Van and Teardrop Builds Specifically

Look for

A compact 35 to 45 amp unit with a clear lithium setting, since small batteries and short cable runs do not need high current.

In this comparison

The PowerMax PM4 45A offers adjustable output and a quick install, and the VEVOR 45A covers small batteries for about $63.

When to Spend More

Spend more if

You want certified safety and no settings; the WFCO WF-9835-AD-CB is UL/CSA listed and auto-detects LiFePO4.

Save if

You are comfortable with a meter; the VEVOR 45A or PowerMax PM4 45A handle lithium for far less.

FAQ

Before You Bring One Home

Do I need a special converter for lithium batteries?

You need one that can reach a lithium charge voltage near 14.2 to 14.6V. A standard 13.6V converter will run loads but leaves LiFePO4 undercharged; units like the PowerMax PM4 45A or WFCO WF-9835-AD-CB solve that.

What size converter do I need for a single 100Ah lithium battery?

Around 35 to 45 amps is a practical match for most 100Ah batteries, which often accept about 50 amps of charge. The PowerMax PM4 45A fits that range.

Is the WFCO auto-detect worth it over an adjustable PowerMax?

If you want no settings and a UL/CSA listing, yes. If you are comfortable using a meter, the adjustable PowerMax gives more control for less money.

How do I set an adjustable converter for lithium?

Check the battery's recommended charge voltage, set the converter to that value with the battery disconnected, and confirm with a meter. Then reconnect and watch voltage rise during charging.

Can a converter heat or protect my lithium battery in the cold?

No. These converters do not monitor battery temperature, so rely on a battery with a low temperature charge cutoff or a heater, and avoid charging LiFePO4 below about 32F.

Is a bigger converter always better?

No. Beyond your battery's accepted charge current, extra amps only add cost, cable size, and heat. The 75 amp PowerMax PM3-75LK makes sense only with two or more batteries.

Bottom line

The short version

Browse more rv converters for lithium batteries on Amazon →

About the author

Bowen Higgins

RV Editor at RV Gear Lab

Bowen covers RV power, water systems, towing and leveling, upkeep and interior comfort, with a focus on matching gear to the rig, the hookups and the way you actually travel.

6 Best RV Converters for Lithium Batteries in 2026: A Practical RV Guide

Our top picks

The Rig Fit Check

What Matters Before You Choose an RV Converter for Lithium Batteries

Amp rating matched to the battery

How the lithium voltage is set

Fixed and maximum voltage limits

Standalone wiring needs

Shore power tolerance

Protection and certification

Why You Can Trust RV Gear Lab

The 6 best rv converters for lithium batteries, explained

How We Built This Shortlist

Lithium voltage control

Right-sizing for small rigs

Standalone install effort

Documented protections and listing

Cost per amp

Match an RV Converter for Lithium Batteries to Your RV

By Battery Setup

By Budget

Adjustable Output vs Auto-Detect

By Install Situation

For Van and Teardrop Builds Specifically

When to Spend More

Before You Bring One Home

Do I need a special converter for lithium batteries?

What size converter do I need for a single 100Ah lithium battery?

Is the WFCO auto-detect worth it over an adjustable PowerMax?

How do I set an adjustable converter for lithium?

Can a converter heat or protect my lithium battery in the cold?

Is a bigger converter always better?

The short version

Bowen Higgins

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