Most RVs need 200–400Ah of LiFePO4 lithium. Add up your daily watt-hours, divide by your system voltage (12 or 24), then add about 20% headroom. A fridge, lights, water pump and device charging run roughly 100–150Ah a day; add an inverter for induction cooking or air conditioning and you're at 300Ah or more. This guide walks you through sizing your bank, choosing 12V vs 24V, and what to look for in a quality LiFePO4 battery.
Ready to upgrade to lithium?
Shop genuine LiFePO4 batteries in stock and shipped from Upland, CA — including the popular Eco-Worthy 12V 280Ah and the Victron LiFePO4 Smart Battery.
Shop LiFePO4 Batteries →Why LiFePO4 over AGM or lead-acid?
Lithium iron phosphate (LiFePO4) has become the default house battery for serious RV builds, and for good reason.
| LiFePO4 lithium | AGM lead-acid | |
|---|---|---|
| Usable capacity | ~100% (full Ah) | ~50% (don't deep-discharge) |
| Weight | ~⅓ to ½ of AGM for same usable Ah | Heavy |
| Cycle life | 2,000–5,000+ cycles | 300–500 cycles |
| Charging | Fast, high acceptance | Slow, tapering |
| Up-front cost | Higher | Lower |
Because you can actually use the full rated capacity, a 100Ah lithium battery delivers roughly the same usable energy as a 200Ah AGM — at a fraction of the weight. Over its lifespan, lithium's cost-per-cycle is usually lower.
How much capacity do you need?
Size the bank to your usage, not to a round number. Work out your daily watt-hours, then convert to amp-hours at your system voltage.
Daily watt-hours ÷ system voltage = amp-hours used per day. Then add ~20% headroom so you never run the bank flat. (If you charge fully every day from solar, you can size closer; if you go days between full charges, size up.)
| How you camp | Daily use | Recommended bank (12V) |
|---|---|---|
| Weekend / occasional | ~100Ah/day | 100–200Ah |
| Off-grid with a fridge | ~150Ah/day | 200–300Ah |
| Full-time / inverter loads (AC, induction) | 250Ah+/day | 300–400Ah+ |
Pair the bank with enough charging to refill it — see our RV solar panel buying guide and how to build a Victron off-grid power system.
Days of autonomy: worked examples
Before you convert to amp-hours, decide how long you want to run without recharging. That's typically 1–2 days for a setup with solar topping up daily, and more if you camp in shade or poor weather. Multiply your daily watt-hours by those days, then divide by your system voltage.
Example: 1,500 Wh/day × 2 days = 3,000 Wh; at 12V that's 250Ah. These figures are before the roughly 20% headroom described above.
| Rig | Daily use | Days of autonomy | Bank |
|---|---|---|---|
| Weekend couple, solar daily | ~1,200 Wh | 1 | ~100Ah at 12V |
| Family rig, some AC | ~3,000 Wh | 1.5 | ~375Ah at 12V (or move to 24V/48V) |
| Full-time off-grid with AC | — | — | Often 400–600Ah-plus, frequently at 24V or 48V |
If you're past roughly 300–400Ah at 12V, consider 24V or 48V and match your inverter/charger to that voltage. If your numbers land at 400Ah of 12V or more, consider the 48V route before you parallel a fourth 12V battery.
Can I add batteries later? With lithium it's best to plan the bank up front and add matched batteries. Mixing old and new batteries, or different chemistries, is not ideal.
12V vs 24V — which for your build?
Most campers run 12V because the appliances, lights and pumps are 12V. But once you're running a large inverter (3,000W+) or a big solar array, 24V halves the current — meaning smaller, cheaper cable and less voltage drop.
- Stick with 12V for typical builds up to ~2,000W of inverter and ~400W of solar.
- Go 24V for big inverters, large arrays, or long cable runs — then use a DC-DC converter to feed your 12V appliances.
Cable and fuse sizing changes with voltage — see our cable & fuse range.
There is also a 48V option for builds that need serious inverter power, and it is worth knowing about before you commit to a big 12V bank. The BLUETTI B4810 packs 5,120Wh into one 51.2V 100Ah module and is designed for the RV5 inverter/charger (5,000W 120V), so the current on the DC side is a quarter of what a 12V bank would carry for the same load, which means thinner cable and less voltage drop.
What to look for in a quality LiFePO4 battery
- BMS (battery management system): protects against over/under-voltage, over-current and short circuit. Non-negotiable.
- Low-temperature protection or heating: LiFePO4 shouldn't be charged below freezing — look for low-temp cutoff or self-heating if you camp in the cold. The Eco-Worthy 280Ah includes built-in low-temp protection.
- Continuous & peak amps: make sure the battery can deliver enough current for your inverter's draw.
- Bluetooth / monitoring: handy for tracking state of charge; or add a separate Victron battery monitor.
Charging it the right way
Lithium wants the right charge profile from every source. Plan for three charging inputs:
- Solar (MPPT): see MPPT vs PWM controllers, the solar buying guide, and shop Victron SmartSolar MPPT controllers.
- Alternator (DC-DC): charge while driving with a DC-DC charger — shop DC-DC converters.
- Shore power: a lithium-profile smart charger or inverter/charger. See our smart battery chargers.
Want to track it precisely? A Victron battery monitor shows true state of charge — see our battery monitors & protection.
Our picks by use-case
- Weekend (200Ah): the Eco-Worthy 12V 280Ah gives you more than enough headroom for weekend use with Bluetooth monitoring built in.
- Off-grid with a fridge (300Ah): 300Ah at 12V plus 300–400W of solar and a SmartSolar MPPT 100/30 or 100/50.
- Full-time (400Ah+): the Victron LiFePO4 NG series is built for demanding full-time use with deep cycle life and Victron ecosystem integration.
Browse the range on our RV lithium batteries collection — genuine LiFePO4, in stock, ships from Upland, CA.
Prefer a drop-in brand to a full system? Matching the capacity bands above, LiTime’s 12V 200Ah Bluetooth (2,560Wh) covers the typical 200Ah weekend bank, the 12V 320Ah Mini packs 4,096Wh into a 14.49 × 7.44 × 10.04 in case for the 300Ah-plus builds, and the 24V 100Ah Bluetooth suits a 24V system. All have a built-in BMS and a 5-year LiTime warranty, and ships free from our warehouse in Upland, California to the lower 48 states.
Short on space for a 300Ah-plus bank? Compare Rich Solar ALPHA 3 MINI vs ALPHA 3 vs ALPHA 6 MINI.
Frequently asked questions
Can I drop lithium into my Black Series without other changes?
Often you can swap the battery, but to charge it properly you'll usually want a lithium-profile converter/charger and ideally a DC-DC charger for alternator charging. Check your existing charger's profile first.
Should I wire batteries in series or parallel?
Parallel keeps the bank at 12V and adds capacity; series raises voltage (e.g. two 12V batteries to 24V). Choose based on whether you need more capacity (parallel) or higher system voltage (series).
Will lithium work in cold weather?
LiFePO4 discharges fine in the cold but shouldn't be charged below freezing. Choose a battery with low-temp cutoff or built-in heating if you camp in winter — the Eco-Worthy 280Ah includes this protection.
Do I need a new charger for lithium?
Usually yes — lithium needs a lithium charge profile. A charger set for lead-acid/AGM won't fully or safely charge LiFePO4. See our battery charger buying guide.
Ready to upgrade your RV battery bank?
Shop genuine LiFePO4 batteries in stock — or grab the Victron Solar Starter Kit to bundle your MPPT controller and battery monitor together.
For a heated, Bluetooth battery with a wake-up function, the three AIMS Power sizes are compared in AIMS Power LiFePO4 104Ah vs 135Ah vs 300Ah.
Shop LiFePO4 Batteries → Shop the Solar Starter Kit →