I have a Lenovo Thinkpad T430, and I just installed Elementary OS a week ago.
Since I've been trying it with no charger I've seen how my battery level is reducing almost every three minutes.
I really have no idea of what to do.
Linux in general doesn't have so well implemented battery saving techniques as windows out of the box but that doesn't mean you cannot try to improve things. Take a look at this article which gives some pointers how to maximize your laptop battery https://www.howtogeek.com/55185/how-to-maximize-the-battery-life-on-your-linux-laptop/ in my case (I have Lenovo Thinkpad X230) installing tlp helped the most so I recommend you to make youself familiar with http://linrunner.de/en/tlp/docs/tlp-linux-advanced-power-management.html there are specific tlp modules created especially for Thinkpads (tp-smapi-dkms and acpi-call-dkms). I hope this helps :-)
Try "powertop" in terminal and check what is eating your battery.