How Long Will a 12V 100Ah Battery Run a TV?

I recently tested how long a 12V 100Ah lithium battery will run a TV.

The results?

My TV ran for 16.5 hours straight off my 12V 100Ah lithium battery. Not bad!

However, how long your battery runs your TV will depend on a number of factors, such as your TV’s power consumption and your inverter’s efficiency.

Based on my test, I’d say that, on average, a TV will run for around 15-20 hours straight on a 12V 100Ah lithium battery. And if you’re using a 12V 100Ah lead acid battery, I’d expect it to last for 7-10 hours of uninterrupted watch time, because lead acid batteries can only be discharged to 50%.

Keep reading for my full test results.

Video: 12V 100Ah Lithium Battery vs TV

I made a 30-second video of my runtime test to accompany this article. Check it out below and consider subscribing to my YouTube channel if you like videos related to lithium batteries and DIY solar power!

Test: How Long Will a 12V 100Ah Battery Run a TV?

To find out how long a TV will run on a battery, I connected my TV (a 55-inch flat screen TV) to a Chins 12V 100Ah LiFePO4 Battery via a Victron pure sine wave inverter. I also connected a Victron SmartShunt to the battery to monitor its state of charge and other specs in real time.

With everything set up, I turned the TV on and started a timer.

I immediately went to Netflix to start watching a show. As the show was running, I periodically checked the battery monitor to see how much power my TV was using. It was usually using between 50 and 120 watts, depending on how bright the TV screen was at any given moment.

Note: You’ll notice the “Time remaining” in the screenshot above. This estimate is based on the power draw at that exact moment. A TV’s power usage changes constantly based on, among other things, the screen’s brightness, so this estimate isn’t very useful for our purposes.

With that, the test was underway, and I just left the TV on as I went about my day.

At 30 minutes in, the battery was at 97%.

I checked the battery with a thermal camera and it was still sitting at around room temperature. (The hot spot in front of the battery is due to the iPad.)

I did another check-in at the 4-hour mark. The battery was at 80%.

It was near midnight at this point and I was sleepy, so I put the TV on a Spotify playlist while I slept.

It may sound like listening to music wouldn’t use that much power, but the TV was actually using around 80 watts most of the time the playlist was running. And I found out at this point that muting the TV usually led to a small reduction of around 5 watts in power consumption.

When I woke up the next morning, I was happy to see the TV hadn’t entered sleep mode and had, in fact, been running all night. The battery was sitting at 14% and the test was nearing the 14-hour mark.

Note: Some people prefer to discharge their lithium batteries only to 20% to maximize battery lifespan. However, most LiFePO4 battery brands are capable of being safely discharged to 0% while still lasting for 2,000 cycles. So I decided to drain my battery all the way to 0% for this test.

Over the course of the morning, I watched some TV and YouTube videos. I was practicing my Baby Shark dance moves as the test neared the 16-hour mark (as one does). The battery was sitting at 1% and I was ready for it to die at any second.

Soon after, the TV shut off. I immediately paused the timer and got the final reading: 16 hours and 26 minutes.

Test completed!

Results

Here are two screenshots from my battery monitor showing state of charge and power usage over the course of the test.

Note: I actually took these screenshots just before the battery died, since the battery monitor I used doesn’t save this data after it loses power.

And here are the final results:

• Runtime: 16.5 hours
• Consumed amp hours: 103Ah (New LiFePO4 batteries can slightly outperform their rated capacity, so that’s to be expected.)
• Consumed watt hours: 1318Wh (at 12.8V)
• Average power draw: 80W
• Average current draw: 6.25A (at 12.8V)

7 Factors Affecting How Long a TV Will Run on a Battery

I ran this test to try to get a rough estimation of how long a 12V battery can run a TV, but the real answer is it depends. Here are some of the main factors that will affect how long your TV lasts.

1. Battery size: Simple put, the greater your battery’s capacity, the longer you can run your TV.
2. Battery type: Lithium batteries often have 100% usable capacity, while lead acid batteries have only 50% usable capacity. So a 120Ah lithium battery can deliver 120 amp hours, while a 120Ah lead acid battery can deliver only 60 amp hours.
3. TV power consumption: Bigger TVs use more power, and some models run more efficiently than others. Your TV’s brightness setting also has a large effect on how much power it uses.
4. Inverter efficiency and power consumption: Unless you have a 12V TV, you’ll need an inverter to run your TV. Inverters can vary widely in their efficiencies and power consumption.
5. Your watch habits: Beyond just how long you watch TV, what you watch can have an effect on how much power your TV uses. I found YouTube videos to generally be brighter than TV shows, for instance, so when watching YouTube videos my TV consumed more power. Also, volume level has a slight impact on TV power usage.
6. Inverter cutoff voltage: Inverters all have minimum input voltages, below which they’ll cut off. A battery’s voltage drops as it drains, so the lower your inverter’s cutoff voltage, the longer your battery will last.
7. Other loads: Any extra loads connected to the battery will use power and shorten the battery’s lifespan.

What Size Battery Do I Need to Run a TV?

Based on my test, I think a 12V 100Ah lithium battery, or a 12V 200Ah lead acid battery, is a great size for running a TV. If you watch the US average of 2.5-3 hours per day, it should last you around 4-7 days before needing to be recharged. That makes it a great size for short RV and camping trips where you don’t have solar panels or grid access for battery recharging.

However, with a properly sized solar panel system — or less than average TV usage — you may be able to get away with a smaller battery, such as a 50Ah lithium battery (or a 100Ah lead acid battery).

These are quick and dirty battery size recommendations, so they may not apply to your specific scenario. And keep in mind that they assume that your TV is the only device your battery is powering, which is often not the case.

If you’re running other devices off the same battery, such as lights and fans, then these estimates go out the window. Be open to buying a second 12V battery and wiring it in parallel to increase your battery bank’s amp hour capacity if you find your battery dying often.

5 Ways to Increase How Long Your Battery Will Run Your TV

1. Turn the TV brightness down. As I was running this test, I noticed that the main thing that affected the TV’s power consumption was how bright the screen was at any given moment. When there was a nighttime scene in a TV show, for instance, the TV would use around 50 watts. When the screen was bright and mostly white, the power consumption would jump to around 120 watts. The easiest and most effective way to reduce your TV’s power consumption is to go into the settings and lower the TV’s brightness level.
2. Get a more efficient inverter. If your inverter isn’t very efficient, or it consumes a lot of power, consider upgrading to a more efficient inverter.
3. Lower the inverter cutoff voltage. Only use this method if you are familiar with your battery type’s voltage curve and are confident that you won’t overdischarge it. (Here is a LiFePO4 voltage chart and lead acid voltage chart.) If your inverter lets you, you can lower the cutoff voltage to a still-safe-but-slightly-lower setting to eek out a little extra runtime.
4. Turn the TV and inverter off when not using. Use sleep timers, if needed, to make sure the TV shuts off when you go to bed. And don’t rely on your TV’s screensavers to save power. I checked the power consumption of the Netflix and Roku screensavers, and they did not reduce the TV’s wattage. The Netflix screensaver consistently used around 80 watts, while the Roku used closer to 100 watts! Also, inverters consume a small amount of power when on, even if they aren’t actively powering any devices.
5. Disconnect the TV when not using. TVs can still consume power when turned off. After my test ended, I checked my TV’s power consumption when off, and for the first 15 minutes or so after turning it off it still consumed around 20 watts. Eventually the power usage did drop to around 0.5 watts, but it wasn’t immediately, like I’d expected.

The Bottom Line

When I timed how long my 12V 100Ah lithium battery ran my 55-inch flat screen TV, it lasted for 16.5 hours straight.

Based on my results, if you watch the American average of 2.5-3 hours of TV per day, I’d expect a 12V 100Ah lithium battery to run your TV for around 4-7 days. For 12V 100Ah lead acid batteries, you can expect 2-3 days of runtime.

But, of course, there are a lot of factors — such as your TV’s average power consumption — that will affect your results.