Maximising laptop battery life

[David Fletcher]

I have a friend, whose old laptop I've refurbished by maxing the RAM,
replacing the failed battery, purging it of XP and putting in Linux on a
new hard drive.

Now, she's got some work assignments coming up to sit with disabled
students in lecture theatres and use the laptop to type up lecture notes
for them.

My question is, will the battery last any longer using a simple text
editing application such as gedit, rather than Libre Office?

My reasoning is that Libre Office is huge overkill for the simple task
of bashing words into the computer, and does loads more work such as
figuring out proportional character spacing with every key stroke, which
must takes loads more processor cycles to accomplish, and is completely
unnecessary for the task.

Is she likely to get longer battery life with a text editor rather than
a word processor?

Thanks for any advice.

Dave