How Long Will a 12V TV Run on a Caravan Battery?

"How long will my battery last with the TV on?" It's one of the most common questions in Australian caravan forums, and it rarely gets a straight answer. The truth is there's a simple calculation behind it, and once you understand the key variables, you can plan your off-grid entertainment around your actual setup rather than guesswork.

What Affects Your TV's Battery Draw?

Three things determine how long your battery will power a 12V TV:

1. The TV's watt draw — smaller screens use less power; smart TVs with bright settings use more
2. Your battery capacity — measured in amp-hours (Ah) or watt-hours (Wh)
3. Your usable battery percentage — lithium batteries can discharge to around 80 to 90 per cent; AGM batteries should only go to 50 per cent to protect lifespan

Getting these three numbers right gives you a reliable estimate rather than a vague "it depends."

The Formula

Here's the straightforward calculation:

Hours of viewing = Usable battery capacity (Wh) ÷ TV watt draw

If you don't know your battery's watt-hours, multiply amp-hours by voltage:

• A 100Ah 12V battery = 1,200Wh
• Usable capacity at 80% (lithium) = 960Wh
• Usable capacity at 50% (AGM) = 600Wh

Real-World Examples

Here's how the maths plays out across common setups.

Small 24-inch 12V TV at 20W

Larger 32-inch smart 12V TV at 40W

Keep in mind these figures assume the TV is the only draw on the battery. In a real caravan setup you'll also have a fridge, lighting, phone charging, and possibly a Starlink or Wi-Fi router running alongside the TV.

How Much Does a Caravan TV Actually Draw?

Watt draw varies significantly between models, so checking the spec sheet matters. As a rough guide:

• 19 to 22-inch 12V TV: 15 to 25W
• 24-inch 12V TV: 20 to 30W
• 27-inch 12V TV: 25 to 40W
• 32-inch smart 12V TV: 35 to 55W

Brands like Englaon publish accurate watt draw figures for their 12V TV range, which makes it easier to do this calculation before you buy. We recommend checking the listed operating wattage (not the maximum or standby figure) when comparing models.

One practical tip: lowering your TV's backlight setting to around 70 per cent can reduce power consumption by 15 to 20 per cent with minimal impact on picture quality. In a dark caravan at night, you're unlikely to notice the difference.

Adding Solar to the Equation

If you have solar panels on the roof, the picture changes considerably. On a sunny day in Australia, a single 200W panel can generate enough power to run a 24-inch 12V TV for most of the day and still top up your battery for evening viewing.

The general rule of thumb: if your solar input exceeds your TV's watt draw during daylight hours, you're drawing essentially free power while the sun is up. You're only really burning stored battery capacity once the sun goes down.

A 200Ah lithium battery paired with 200W of solar covers most caravanners' entertainment needs comfortably, even in winter when solar generation is lower.

Accounting for Starlink and Other Devices

Starlink Mini draws around 25 to 40 watts on its own. Running it alongside a 24-inch 12V TV puts your combined draw somewhere between 50 and 70 watts. On a 100Ah lithium battery, that gives you roughly 13 to 19 hours of simultaneous streaming before hitting the 80 per cent discharge threshold.

For extended off-grid trips, sizing up to 200Ah of lithium storage is a worthwhile investment if you want to stream comfortably without rationing power.

Quick Reference Summary

• Check your TV's actual operating wattage on the spec sheet
• Use the formula: usable battery Wh ÷ TV watts = hours of viewing
• Lithium batteries give roughly 80% usable capacity; AGM gives 50%
• Factor in your other loads (fridge, Starlink, lighting) for a full picture
• Lowering backlight and disabling Wi-Fi when not streaming reduces draw noticeably

Get these figures right before you leave home and you'll have a clear idea of what your setup can genuinely handle out in the bush.