Buying Guide
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 Hardcastle's RV Editors
11 min read6 products evaluated
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.
Hardcastle’s RV field notes
The Rig Fit Check
A quick way to connect the shortlist to the space, workload and ownership details that matter after the box arrives.
- 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
The Practical Shortlist
A road-tested-thinking look at 6 options, organized around the job each one suits best.
Best Overall
PowerMax PM4 45A RV Converter with 3-Stage Charger, Lithium Compatible
small trailers and vans with one or two lithium batteries
Our take Check price for PowerMax PM4 45A RV Converter with 3-Stage Charger, Lithium Compatible (opens in a new tab)
Best Auto-Detect
WFCO WF-9835-AD-CB 35A Deck-Mount Converter Charger, Auto-Detect
owners who want certified, hands-off lithium charging
Our take Check price for WFCO WF-9835-AD-CB 35A Deck-Mount Converter Charger, Auto-Detect (opens in a new tab)
Best Adjustable Alternative
PowerMax PM3-45-SME 45A Converter Charger, Adjustable Lithium
owners who want a PowerMax PM3 series unit
Our take Check price for PowerMax PM3-45-SME 45A Converter Charger, Adjustable Lithium (opens in a new tab)
Best 4-Stage Pick
RecPro 45A RV Power Converter and Battery Charger
owners loyal to an RV parts brand
Our take Check price for RecPro 45A RV Power Converter and Battery Charger (opens in a new tab)
Best Budget
VEVOR 45A RV Power Converter Battery Charger
teardrops and vans with a small lithium battery
Our take Check price for VEVOR 45A RV Power Converter Battery Charger (opens in a new tab)
Best for More Headroom
PowerMax PM3-75LK 75 Amp Converter, Lithium Compatible
owners with two or more lithium batteries
Our take Check price for PowerMax PM3-75LK 75 Amp Converter, Lithium Compatible (opens in a new tab)
Why Each Pick Made the Cut
Best Overall1 of 6
PowerMax PM4 45A RV Converter with 3-Stage Charger, Lithium Compatible on Amazon (opens in a new tab)
Choose PowerMax PM4 45A RV Converter with 3-Stage Charger, Lithium Compatible for output adjusts to match your lithium charge voltage.
Best for
- small trailers and vans with one or two lithium batteries
Why it made the shortlist
PowerMax PM4 45A RV Converter with 3-Stage Charger, Lithium Compatible is positioned for small trailers and vans with one or two lithium batteries. The documented setup centers on 45A, adjustable 13V to 16.5V, 3-stage, LiFePO4 compatible, no-rewire install.
The feature doing most of the work here is output adjusts to match your lithium charge voltage. Its 45A, adjustable 13V to 16.5V specification sits at the lower end of the comparable range in this 3-product comparison. Treat the battery platform and included charger as part of the fit, not just the headline number.
The practical constraint here is upper adjustment range can overcharge if misset. Confirm whether the battery and charger are included with the exact package. Check platform compatibility and published runtime against the area or workload you need to cover.
Key dimensions & specs
- 45A, adjustable 13V to 16.5V
- 3-stage, LiFePO4 compatible
- No-rewire install
Pros
- 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
Cons
- Upper adjustment range can overcharge if misset
- No UL listing documented
Best Auto-Detect2 of 6
WFCO WF-9835-AD-CB 35A Deck-Mount Converter Charger, Auto-Detect on Amazon (opens in a new tab)
WFCO WF-9835-AD-CB 35A Deck-Mount Converter Charger, Auto-Detect makes the shortlist because auto-Detect handles lithium with no settings.
Best for
- owners who want certified, hands-off lithium charging
Why it made the shortlist
This model is aimed at owners who want certified, hands-off lithium charging. The documented setup centers on 35A, auto lead/LiFePO4, full output down to 100V, uL/CSA listed.
The most useful documented advantage is auto-Detect handles lithium with no settings. Its Full output down to 100V specification sits at the upper end of the comparable range in this 3-product comparison. Treat the battery platform and included charger as part of the fit, not just the headline number.
The main limitation to plan around is most expensive per amp in this list. Confirm whether the battery and charger are included with the exact package. Check platform compatibility and published runtime against the area or workload you need to cover.
Key dimensions & specs
- 35A, auto lead/LiFePO4
- Full output down to 100V
- UL/CSA listed
Pros
- Auto-Detect handles lithium with no settings
- Full output even at 100V shore input
- UL/CSA listed and FCC compliant
Cons
- Most expensive per amp in this list
- 35A charges slower under heavy loads
Best Adjustable Alternative3 of 6
PowerMax PM3-45-SME 45A Converter Charger, Adjustable Lithium on Amazon (opens in a new tab)
The strongest case for PowerMax PM3-45-SME 45A Converter Charger, Adjustable Lithium is adjustable output for lithium setups.
Best for
- owners who want a PowerMax PM3 series unit
Why it made the shortlist
For owners who want a PowerMax PM3 series unit, this is one of the more relevant configurations in the shortlist. The documented setup centers on 45A regulated output, adjustable lithium output, standalone deck mount.
Its case starts with adjustable output for lithium setups. Against the other 5 picks, the useful comparison starts with 45A regulated output and adjustable lithium output. Those details show whether its configuration suits the job better than a neighboring recommendation.
The trade-off worth checking first is adjustment range not listed. Confirm the exact model number and included components before ordering. Check dimensions, compatibility and maintenance needs against the way you plan to use and store it.
Key dimensions & specs
- 45A regulated output
- Adjustable lithium output
- Standalone deck mount
Pros
- Adjustable output for lithium setups
- 45A suits single-battery small rigs
- Thermal and reverse-polarity protection
Cons
- Adjustment range not listed
Best 4-Stage Pick4 of 6
RecPro 45A RV Power Converter and Battery Charger on Amazon (opens in a new tab)
RecPro 45A RV Power Converter and Battery Charger is the better fit when owners loyal to an RV parts brand.
Best for
- owners loyal to an RV parts brand
Why it made the shortlist
The intended use case is owners loyal to an RV parts brand. The documented setup centers on 45A, 4-stage charging, lead and lithium compatible, sold in 35A to 100A.
What separates it on paper is 4-stage charging for long storage periods. Against the other 5 picks, the useful comparison starts with 45A, 4-stage charging and lead and lithium compatible. Those details show whether its configuration suits the job better than a neighboring recommendation.
Before committing, account for lithium voltage not published. Confirm the exact model number and included components before ordering. Check dimensions, compatibility and maintenance needs against the way you plan to use and store it.
Key dimensions & specs
- 45A, 4-stage charging
- Lead and lithium compatible
- Sold in 35A to 100A
Pros
- 4-stage charging for long storage periods
- Runs 12V loads while charging the battery
- Same line available in larger sizes
Cons
- Lithium voltage not published
- Pricier than the VEVOR with fewer details
Best Budget5 of 6
VEVOR 45A RV Power Converter Battery Charger on Amazon (opens in a new tab)
Choose VEVOR 45A RV Power Converter Battery Charger for dedicated LiFePO4 charging mode.
Best for
- teardrops and vans with a small lithium battery
Why it made the shortlist
VEVOR 45A RV Power Converter Battery Charger is positioned for teardrops and vans with a small lithium battery. The documented setup centers on 45A, LiFePO4 mode, fixed 13.0V, 14.6V, 16.5V, six listed protections.
The feature doing most of the work here is dedicated LiFePO4 charging mode. Its Fixed 13.0V, 14.6V, 16.5V specification sits at the lower end of the comparable range in this 3-product comparison. Treat the battery platform and included charger as part of the fit, not just the headline number.
The practical constraint here is 16.5V fixed mode is unsafe for 12V lithium. Confirm whether the battery and charger are included with the exact package. Check platform compatibility and published runtime against the area or workload you need to cover.
Key dimensions & specs
- 45A, LiFePO4 mode
- Fixed 13.0V, 14.6V, 16.5V
- Six listed protections
Pros
- Dedicated LiFePO4 charging mode
- Copper cable included in the box
Cons
- 16.5V fixed mode is unsafe for 12V lithium
- Sized by VEVOR for small 30 to 50Ah batteries
Best for More Headroom6 of 6
PowerMax PM3-75LK 75 Amp Converter, Lithium Compatible on Amazon (opens in a new tab)
PowerMax PM3-75LK 75 Amp Converter, Lithium Compatible makes the shortlist because most amps per dollar in this list.
Best for
- owners with two or more lithium batteries
Why it made the shortlist
This model is aimed at owners with two or more lithium batteries. The documented setup centers on 75A rated, lithium compatible, 3-stage smart charging, series or parallel capable.
The most useful documented advantage is most amps per dollar in this list. Against the other 5 picks, the useful comparison starts with 75A rated, lithium compatible and 3-stage smart charging. Those details show whether its configuration suits the job better than a neighboring recommendation.
The main limitation to plan around is too much current for one 100Ah battery. Confirm the exact model number and included components before ordering. Check dimensions, compatibility and maintenance needs against the way you plan to use and store it.
Key dimensions & specs
- 75A rated, lithium compatible
- 3-stage smart charging
- Series or parallel capable
Pros
- Most amps per dollar in this list
- 3-stage charging protects battery life
- PM3 units can be paralleled for more output
Cons
- Too much current for one 100Ah battery
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.
What Matters Before You Choose an RV Converter for Lithium Batteries
Key buying criteria so you get the right fit the first time.
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.
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.
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.
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.
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.
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.
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 |
Scroll sideways to see every column.
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.
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
Best overall: PowerMax PM4 45A RV Converter with 3-Stage Charger, Lithium Compatible — best overall pick in this roundup. See the full verdicts above for every pick, with pros, cons and who each one suits.
Browse all rv converters for lithium batteries on Amazon — Prime-eligible options with current pricing.