The Samsung Galaxy S20 Ultra has a large 5,000mAh battery, which is expected to last longer on a charge. However, while the phone offers a lot of endurance with its 60Hz mode display, using a 120Hz refresh rate on the Galaxy S20 Ultra's screen will put a significant strain on battery life.

We put the Galaxy S20 Ultra through four battery tests. In these tests, we ran continuous web surfing on cellular (in this case T-Mobile 5G) with the screen brightness set to 150 nits. Two of the tests were performed with the display set to 60 Hz mode and two were performed in 120 Hz mode.

With 60Hz mode on, the Galaxy S20 Ultra averaged an impressive 11 hours and 58 minutes, which is enough to put this device on our Best Smartphone Battery Life list. We consider smartphones that exceed 11 hours to be very good, and those that approach or exceed 12 hours to be excellent.

However, turning on the Galaxy S20 Ultra's 120Hz mode was a very different story. The Android phone's runtime was only 9 hours and 13 minutes, nearly 3 hours less than with 60Hz turned on.

The good news is that you can easily switch between 60Hz and 120Hz in the Samsung Galaxy S20 Ultra's settings. 60Hz mode is enabled by default.

Battery life results for the Galaxy S20 Ultra are good, but a step short of the Galaxy S10 Plus' 12:35 runtime. There are several possible reasons for this. First, the Galaxy S20 Ultra's display is 6.9 inches, larger than the 6.4 inches of the S10 Plus. Second, the S20 Ultra has a 5G modem, which is likely to consume more power than 4G.

Still, the Galaxy S20 Ultra Galaxy Note 10 Plus beat the Galaxy Note 10 Plus with a similarly sized 6.8" display; the Note 10 Plus lasted only 10 minutes 47 seconds on its 4,300 mAh battery So the S20 Ultra's 5,000 mAh battery is definitely an advantage.

The iPhone 11 Pro Max recorded a similar time to the S20 Ultra at 11 minutes 54 seconds. Apple's flagship model has a 6.5-inch display with a refresh rate of 60 Hz. However, rumors suggest that the iPhone 12 will offer a 120 Hz rate, similar to the ProMotion displays on the iPad and iPad Pro.

In short, you can get great battery life with the Samsung Galaxy S20 Ultra, but you will need to get the display to 60Hz.