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How to Size a LiFePO4 Battery for Your Needs (Camping, RV, Solar)

How to Size a LiFePO4 Battery for Your Needs (Camping, RV, Solar)

By Portable Batteries Austraila

Published: August 4, 2025

When choosing a LiFePO4 battery for your caravan, camping setup, or solar system, selecting the right size is critical. Too small, and you’ll run out of power early; too large, and you’ll overpay or carry unnecessary weight. Here’s how to size your LiFePO4 battery properly.

Step 1: Calculate Your Daily Power Usage

Start by listing all the devices you plan to power regularly and estimate their daily energy use:

Power (Watts)

Device

Usage Hours per Day

Daily Usage (Wh)

10

LED lights

Feature

10 x 5 = 50 Wh

10

Small fridge (12V)

5

50 x 24 = 1200 Wh

20

Phone/laptop charging

24

20 x 3 = 60 Wh

40

Pump/other

2

40 x 2 = 80 Wh

Total Daily Usage

1390 Wh

This total (in watt-hours, Wh) is key to sizing your battery.

Step 2: Consider Depth of Discharge (DoD)

One major advantage of LiFePO4 batteries is their deep discharge capability—typically up to 80–90% usable capacity without damage.

For example, if you need 1390 Wh per day:

- Assuming 90% usable DoD, battery size needed = 1390 Wh / 0.9 ≈ 1545 Wh

Step 3: Account for Days of Autonomy

If you want backup power for several cloudy days or off-grid periods without solar recharge, multiply your daily usage by the number of days:

- For 3 days autonomy: 1545 Wh x 3 = 4635 Wh battery capacity

Step 4: Factor in Efficiency and Losses

Include roughly 10–15% additional capacity to cover inverter inefficiencies and battery aging.

- Add 15%: 4635 Wh x 1.15 ≈ 5330 Wh

Step 5: Match to Available Battery Sizes

At portablebatteries.com.au, we have a:

- Mid-range 2400Wh LiFePO4 battery

- Higher-range 3600Wh LiFePO4 battery/products/pecron-e3600lfp

- Expansion battery (can be added for extra capacity)

To meet 5330 Wh you could combine a 3600Wh battery + expansion battery or use multiple batteries in parallel.

Other Sizing Tips

- Start with your most critical loads: If full power for all devices is not needed, size your battery around essentials.

- Include future expansion: Leave room to add batteries as your power needs grow.

- Consult product specs carefully: Know each battery’s usable capacity.

Ready to size your battery with confidence?

Learn more about:

- LiFePO4 vs AGM & Lead Acid: Which Is Best for Off-Grid Power?/blogs/batteries/lifepo4-vs-agm-lead-acid-which-is-best-for-off-grid-power

- Best Portable Power Stations for RVs: Australian Buyer’s Guide 2025

- How to Install a LiFePO4 Battery in Your Caravan/RV

Related Articles:

LiFePO4 vs AGM & Lead Acid: Which Is Best for Off-Grid Power?

LiFePO4 vs AGM & Lead Acid: Which Is Best for Off-Grid Power?

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Best Portable Power Stations for RVs: Australian Buyer's Guide 2025

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How to Install a LiFePO4 Battery in Your Caravan/RV

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Official Australian Supplier for PECRON

Australia (English) All Prices In AUD

ABN: 80 213 109 779