How to Convert Your RV to Lithium Batteries: A DIY Install Guide

Where This Guide Comes From

This guide follows a real conversion filmed by the DoItYourselfDad channel — a travel-trailer owner swapping his 61Ah lead-acid battery for a 200Ah LiTime lithium battery as the first step of a full electrical upgrade. It's a ground-level install: what to switch off, where to drill, how to make a cable, and what to do when the charger doesn't like lithium. The video is right here if you want to watch it alongside:

Why do this at all? Because the math is genuinely lopsided in lithium's favor. That single swap is roughly four times the usable power — and it changes how long you can boondock without thinking about the battery at all.

Why Convert: The 4x Math

With a typical lead-acid deep cycle battery, you can only deplete it 50–80% before you start damaging it. That's the practical floor: half your rated capacity is actually usable. With lithium, you can take it down to essentially zero — and even then, a lithium cell handles the cycle far better than a lead-acid one does.

There's a second, less obvious difference. A lead-acid battery's voltage sags as it depletes; lithium has a very flat discharge curve. That means your appliances keep running at full voltage right up to the end, and you actually get more usable juice out of every rated amp-hour. For the owner in the video, going from 61Ah lead-acid to 200Ah lithium worked out to roughly four times as much usable power — same footprint, four times the camping time off-grid.

Safety First: Kill the Power, Then the Battery

Step one is non-negotiable: make sure there's no power running through the trailer.

• Turn off the 12V power switch on the line feeding the trailer.
• Then unplug the entire trailer from shore power.
• Only then remove the old battery.

And when you pull the terminals, be very careful not to let your wrench touch both terminals at once. It makes a spectacular short — and it can be genuinely dangerous. One commenter added the right order: remove the negative first, and install the negative last. That way the tool you're using is never the thing that completes a circuit against the chassis. Also worth noting from the comments: if the old battery's grounded to the trailer frame, take the ground wire off first, and keep the wrench away from the frame and any propane lines while you work — a short to frame near a propane tank is a fire risk, not just a spark.

Choose Where the Battery Lives

Here's the decision that separates a lazy install from a good one. You don't have to put the new lithium battery where the old one sat. The video moved it inside the trailer, into the front storage bay, and the reasons are worth copying:

• Theft: lithium batteries are expensive, and a box on the tongue is easy to steal. Inside the trailer, it's out of sight.
• Temperature: lithium doesn't like being charged when very cold or very hot. Inside the living space, the battery rides along with you at a reasonable temperature — which protects both capacity and lifespan.
• Bonus space: moving it inside freed up the tongue box for leveling blocks and gear.

You don't have to go this route — a drop-in size that fits the original box will roughly double your capacity with zero relocation work. But if you're going bigger, inside is the smarter home.

Run the Cables Inside

Moving the battery inside means getting the battery cables into the trailer. The video's approach:

• Drill a hole next to the existing gas-line pass-through, sized for a flexible wire loom.
• Before drilling, get under the trailer and check what's on the other side of the floor. The owner deliberately chose one side of the pass-through because the other side had a beam in the way — a drill bit meeting a beam (or worse, a fuel line) is a bad afternoon.
• Feed the loom through the hole and pull the cables up inside.

One wiring note from the video: match the existing cable gauge. If the positive lead isn't long enough to reach the new location, extend it with the same gauge wire or larger — never smaller. Bigger is safe; smaller is how you get voltage drop and heat.

Extending Wires the Right Way

If you need to make a new battery cable, the video shows the simple version that works:

1. Cut back the insulation a little — but not so deep that you nick the copper core (a nicked core is a future break).
2. Slide a piece of heat-shrink over the wire first, so it's there when you need it.
3. Crimp a terminal onto the end with a proper crimping tool — a hammer crimper works fine.
4. Slide the heat-shrink over the crimp and shrink it with a lighter or heat gun.

Secure the Battery Properly

A 200Ah lithium battery is heavy, and a trailer bounces. The video's solution is simple and correct: screw D-rings to the floor and run a strap over the top of the battery. If there's a trim piece that blocks the bay, use it as part of the retention. The battery should not be able to slide, tip, or shift under braking — a sliding battery is a shorted battery waiting to happen.

Once it's in place, attach positive and negative leads. The battery in the video came with safety caps for the terminal bolts — put them on. They prevent a dropped tool or a loose strap buckle from shorting the terminals later.

First Power-On Test

The fun part: flip the trailer's power back on and test the lights. If everything works — congratulations, you're running lithium. In the video's words, you'll now be able to camp much longer boondocking before the battery runs out.

Don't Forget the Charger Question

The project is not done when the lights come on. The one thing everyone forgets: does your inverter/charger support lithium? Some do and some don't.

• If your charger supports lithium profiles — you're done, nothing left to do.
• If it doesn't — a lead-acid charger will undercharge or mistreat a lithium bank, so you'll need a lithium-compatible converter or a DC-DC charger. The video points to a separate 20-minute install with basic hand tools.
• If you tow and charge from the truck alternator, check that path too — one commenter warns that without a DC-DC charger, alternator charging a lithium bank while driving can cook the alternator when the battery pulls a huge charge current.

This is the step that decides whether your new lithium bank actually gets full — and it's exactly the kind of thing a spec-sheet vendor won't tell you, because it's about your existing equipment, not the battery.

Bottom Line: Should You Do This Yourself?

1. The payoff is real: roughly 4x usable power from one swap — more boondocking, flatter voltage, longer life.
2. Safety is two sentences: power off and unplugged first; negative terminal off first and on last; wrench never bridges.
3. Location matters: inside the trailer for theft and temperature; same box if you want the easy 2x.
4. Cable work is the weak point: same-or-larger gauge, clean crimps, heat-shrink everything.
5. Secure it like it's cargo: D-rings, straps, terminal caps.
6. Check the charger before you trust it: lithium-compatible charging is the real last step, and it's the one most installs skip.

If you're comfortable turning off power, drilling a hole, and making a crimp, this is a genuinely doable weekend job — and the upgrade makes every trip after it better.

And if you're not hunting for a consumer brand but need the lithium RV battery itself — a custom LiFePO4 pack at a specific voltage and capacity, an OEM or ODM project, or wholesale supply for your own battery line — that's what we do. Dajiu Energy is a Chinese manufacturer building LiFePO4 batteries for RVs, homes, golf carts and portable applications since 2017. Our product range covers LiFePO4 drop-in replacement batteries, EV and golf cart batteries, wall-mounted home storage, portable power stations, commercial energy storage and battery swap cabinets — explore the full lineup in our product center, or browse more buying guides. Tell us your voltage, capacity and size, and we'll engineer the pack to hit it.

What Our Readers Asked (Top Comments on the Video)

These are the most-liked comments on the source video, with our practical answers. The original creator did not reply to these threads, so the answers below are ours — written the way we'd answer a customer on the shop floor.

Source video: DoItYourselfDad — "How to Convert to Lithium Batteries - Upgrade for RVs and Travel Trailers" (youtube.com/watch?v=J4OU9TAONbw). Comment excerpts are quoted verbatim from the video's top comments; the original creator did not reply to these threads, so all answers are Dajiu Energy's own.