# What Lithium chemistry in phones' (now) 3.8V batteries?

I'm specifically looking for the discharge tolerances...can communicate with the charge controller on the phone and want to increase the discharge depth from 3.5V to say 3.1-3V for longer battery life. The cell won't sleep until at least 3V or something, damage doesn't occur until 2.7V on the standard lithium batteries used in phones a few years ago, and a replacement is only $12.50 so I want to see what I can do. • Datasheet says? – Ignacio Vazquez-Abrams Aug 5 '14 at 21:47 • I don't have one for the battery... LG Nexus 5...BL-T9 reads the battery model number-- d3nevzfk7ii3be.cloudfront.net/igi/FkwkjeYpMZpDxkVV.huge looking for more on the power controller... – paIncrease Aug 5 '14 at 22:01 • +1 - there - that's helped your rep a little :-). As Bruce says - not a vast amount under 3V5 but it does depend on load. 16 hours would typically be rather heavy standby with some TX/RX. – Russell McMahon Aug 6 '14 at 2:30 ## 1 Answer Modern Lithuim-ion Polymer batteries don't like being discharged to 2.7V, and there's little to gain from going below 3.5V anyway because at that voltage there is almost no capacity left. • I had no idea. Thank you. I would vote up but... and whyTF can't I comment on other posts? Or bring this up in Meta? Do I need to fax my$120k top-5-EE-schools diploma to someone? In spite of formatting issues sometimes I DO know what I'm talking about and 50 reputation is...I can't even. – paIncrease Aug 5 '14 at 22:52
• @Rancur3p1c Stick around, add a good answer when you see a question you can help with, and you'll get to 50 rep (and thus freedom from the spammer-gate comment restriction) within a few days. – Chris Stratton Aug 5 '14 at 23:05
• @ChrisStratton can't add answers without rep. – paIncrease Aug 5 '14 at 23:10
• On most questions you can, a few where we were getting lots of bad answers are protected with very low reputation requirement to post one. Needless to say, don't post answers just in hopes of getting rep (you can loose it for bad ones), but in places where you can make a helpful contribution. – Chris Stratton Aug 5 '14 at 23:12
• oh, well maybe that's why, and that makes sense, I thought it was across the board @ChrisStratton. No, I wouldn't post answers just for the rep, but I definitely have had input on related questions to what I was asking, that I couldn't give – paIncrease Aug 5 '14 at 23:44