13 R1, has terrible battery life

Is it running the original battery? If so, that's almost seven years old and is at the end of it's life -- actually well beyond its expected lifespan.  Replace the battery.

Agreed. We show it shipped from Dell in February 2015.

how would i get it replaced out of warranty though? i asked support for an out of warranty repair and they just said no

You can source a battery from multiple places (it's unlikely Dell will have them, as the system is more than five years old).  Any computer shop can change the battery if you're unable or unwilling to do it yourself.

One source:

https://www.goadapter.com/original-51wh-dell-alienware-13-r1-battery-p-81443.html?gclid=Cj0KCQjwpf2IBhDkARIsAGVo0D2Ir9SLFGhDc5iJKrhl09l4yYB9ieDhfabL921brxxStAwcvH3jP5MaAvy_EALw_wcB

Hi @jade west  for the typical user, noticeable reduction in battery run time generally will be observed after 18 to 24 months. For a power user, reduction in battery run time generally may be experienced within 18 months. Dell recommends buying a new OEM laptop battery when the run time does not meet your needs. Dell Laptop Battery - Frequently Asked Questions | Dell US 

New Alienware 13 R1, 13 R2 OEM Original 4-cell Laptop Battery 51Wh is DP/N 3V806. 

Laptop without battery is designed to function as Desktop on ac adapter power. Getting a good new replacement battery is now difficult, use Amazon, eBay, etc, to get extra purchase protection. When replacement arrives ensure it has white label, DP/N is 3V806, and that year/month date beneath square matrix is less than six months. 

Watch the following YouTube video to determine if you or colleague have the necessary skills to undertake battery replacement. Battery is located deep within laptop and care must be exercised so that other parts are not damaged. 

I recommend disabling all the startup apps in the task manager except windows defender. then I'd go to settings and disable all background apps. then restart the computer and also try running the power plan in power saving and then normal mode.