It sucked my battery down by almost 20% overnight. That is totally unacceptable. So I gave up on Lineage and switched to another ROM. 3% overnight which is a vast improvement. And it uses a lot less memory and storage space.Not sure about a major diffference in battery usage between Stock G7 rom and 18.1 yet.
I am getting about 10% reduction in battery charge on standby mode overnight (airplane mode) which was the same as before.
As for active screen use, still too early for me to tell on 18.1 to see if there has been a significant reduction in battery life during use.
I seemed to burn through my battery the first day a bit but I was doing a heck of a lot. I need more time to gather battery metrics