Question about Lenovo Yoga 720-13IKB

I have owned this device for a month. The i7 and the fantastic display are a power hog. With the "energy saving mode", "power saving mode" and display 50% options switched on, the device lasts 4-5 hours. No more. That is the compromise. Possibly look for a weaker device for school.... Otherwise, I can only recommend the i7 Yoga. It's a great device that I use every day, every chance I get.

The battery performance on the Yoga shows a good 3 hours runtime at 100%. Have another Thinkpad, less slim and twice as heavy, shows about 1 hour more. Somewhere there is a compromise. If you don't have a mains connection within reach, try using a power bank to bridge the gap...

The battery is 48Wh. When I compare it to my Surface Pro 4, which has a similar U-series i5 with 15W TDP but only 8GB RAM, and a slightly smaller display (12.5"), I think the runtime is roughly proportional to the size of the battery.
My Surface Pro 4 has around 38Wh and lasts 4-6h, depending on what I do. Then the Yoga here should last 5-7h already. So if you're spending a long day at uni and need the laptop all the time, it might run out.