Camping Battery Calculator | RV Battery Capacity & Size

🔋 Camping Battery Calculator

Calculate the battery capacity you need for your RV, camper van, or off-grid camping setup

⚡ Quick Presets
⚙️ System Settings
🔌 Appliance Loads

Check each appliance you use, then adjust watts and daily hours as needed. Wh/day updates automatically.

On Appliance Watts Hours/Day Wh/Day
LED Lights
12V Fan
12V Refrigerator
Phone / Tablet Charging
Laptop
TV / Monitor (12V LED)
CPAP Machine (no humidifier)
Electric Blanket / Heated Pad
Water Pump
USB Devices / Smart Chargers
🔋 Battery Sizing Results
Daily Power Usage
Wh per day
Total Energy Needed
Wh (with days & buffer)
Minimum Battery Ah
Ah required
Recommended Bank Size
Ah (rounded to 50Ah)
🔋 Battery Type Guide
Lead Acid
50%
Usable DoD
200–300 cycles
Lowest upfront cost
Heavy, needs maintenance
AGM
80%
Usable DoD
400–600 cycles
Sealed, no maintenance
Best mid-range value
Gel
80%
Usable DoD
500–1,000 cycles
Vibration resistant
Good for rough roads
LiFePO4
90%
Usable DoD
2,000–5,000 cycles
Lightweight, fast charge
Best long-term value
📋 Appliance Wattage Reference
Appliance Typical Watts Avg Hrs/Day Est. Daily Wh Notes
LED Lights10–20W4–6h50–120 WhInterior strip or dome lights
12V Fan15–35W4–8h75–280 WhRoof vent fan or oscillating fan
12V Compressor Fridge30–60W24h (cycles)360–720 WhLargest single load in most RVs
Phone / Tablet Charging10–20W2–3h20–60 WhPer device, varies by charger
Laptop45–90W3–6h135–540 WhVia 12V adapter or inverter
TV / LED Monitor30–80W2–4h60–320 Wh12V TVs draw much less than AC models
CPAP (no humidifier)30–40W7–8h210–320 WhHumidifier adds 60–100W extra
Electric Blanket45–75W4–6h180–450 Wh12V models draw less than AC versions
Water Pump40–80W0.5–1h20–80 WhOnly runs while a tap is open
USB Hub / Smart Devices10–30W4–8h40–240 WhGPS, speakers, lights, dashcam
📊 Wh to Ah Conversion (12V & 24V)
Daily Usage 12V Raw Ah 12V Ah (AGM 80%) 12V Ah (Li 90%) 24V Raw Ah
200 Wh16.7 Ah20.8 Ah18.5 Ah8.3 Ah
400 Wh33.3 Ah41.7 Ah37.0 Ah16.7 Ah
600 Wh50.0 Ah62.5 Ah55.6 Ah25.0 Ah
1,000 Wh83.3 Ah104.2 Ah92.6 Ah41.7 Ah
1,500 Wh125.0 Ah156.3 Ah138.9 Ah62.5 Ah
2,000 Wh166.7 Ah208.3 Ah185.2 Ah83.3 Ah
📦 Common Battery Bank Sizes
Bank Size Total Wh (12V) Usable Wh (AGM) Usable Wh (LiFePO4) Typical Use
50 Ah600 Wh480 Wh540 WhOff-grid tent, 1 night
100 Ah1,200 Wh960 Wh1,080 WhWeekend camper, basics only
150 Ah1,800 Wh1,440 Wh1,620 WhVan life, 1–2 days moderate use
200 Ah2,400 Wh1,920 Wh2,160 WhFull RV, 1–2 days
300 Ah3,600 Wh2,880 Wh3,240 WhOff-grid extended stay
400 Ah4,800 Wh3,840 Wh4,320 WhFull-time RV living
💡 Sizing Tips
Plan for 2–3 Days Without Charging: Even with solar panels, overcast days happen. Size your battery bank for 2–3 days of full usage to avoid running low. A 20% safety buffer on top of your calculated requirement is a reliable starting point for most RV setups.
Your Fridge is the Biggest Load: A 12V compressor fridge typically runs 24 hours, consuming 360–720 Wh per day — more than any other appliance. Design your battery bank around this load first, then add everything else. LiFePO4 batteries handle continuous high-draw loads most efficiently.

In the heart of your camper, the battery has only one important task: it keeps everything operating. Whether you travel by van, caravan, tent or boat, that battery delivers the 12 or 24 volts that your devices require. Without a reliable source of energy you simply will stay in darkness.

The lights will not shine, the water pump will not operate, and your electronic devices will become only fancy weights.

How to Choose a Battery for Your Camper

When you choose a new battery, you have several options. Lead acid batteries are the cheapest, but they operate well only if you mostly stay in campgrounds with electrical connection. If you want something stronger, there are AGM and gel batteries that last better in difficult conditions.

And then are LiFePO4 lithium batteries; a lot of expert travellers genuinely advocate them. Lithium batteries offer more capacity in the same space, charge much more quickly and weigh almost half compared with traditional lead acid systems. This smaller weigt helps to save a bit of fuel during the journey.

Some folks favour an entirely other way: two 6-volt “deep cycle” batteries. When one binds them together to do 12 volts, one can use until 75 or 80 percent of their capacity, instead of the usual limit of 50 percent. That method is popular with owners already for almost twenty years.

The secret is to buy them as a matching pair and substitute both simultaneously, when they fail.

LiFePO4 batteries accomplish almost all needs, they are efficient, operate well with solar panels and easily fit in tight spaces. One alone lithium battery can operate a fridge, fan and all lights without any problems. Even so, there is one important detail: although lithium operates under freeze, charging it in very cold weather without protection can dammage the cells.

The most modern models already have built-in protections. Some self-heating versions require at least 800 watts of solar panels only to operate the internal heater.

Your budget certainly will affect your decision. A basic lead acid battery from a normal store, together with some used solar panels and a simple charger, will suffice for basic lights and to load your phone. But for a long time without connection, lithium batteries are better.

The prices fell considerably recently. 100Ah lithium battery can safely operate a fridge, load devices and light lights and computer during three or four days, even without use of solar panels.

When you drive, the electrical system of the car charges your batteries through that seven-pin connection. When you arrive at a modern campground, you simply connect the external energy. Newest campers already come with lithium-ready converters, so solar can rule everything without repeating the wiring.

If you plan long trips in natural places, upgrading the batteries and installing solar panels become necessary. One big battery usually operates better than two little ones in parallel, especially when you lackspace.

Camping Battery Calculator | RV Battery Capacity & Size

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