The charge regime for lithium ion is cc/cv, The charger goes at high current for the first 80-90% depending on charge rate until the cell reaches 4.2 volts, then the rate ramps down to hold 4.2 until full. That's why they will quote high amounts of charge in a half hour for quick charge 2.0, the last little bit takes longer.
You know some things about lithium batteries, nice to see! My 950 XL, however, is not acting exactly like this and it perplexes me. Some of this must be a firmware issue, but some may be hardware.
Time - % complete - estimated time to charge - charge current
2:45 - start - 63 minutes - 1.8A
3:45 - 55% - 32 minutes - 1.4A
4:15 - 71% - 21 minutes - 1.4A
4:55 - 86% - 10 minutes - 1.2A
5:10 - 94% - 4 minutes - 0.7A
5:20 - 98% - 1 minutes - 0.5A
5:27 - 100% - 0 minutes - 0.4A
It takes my phone another hour or so for the charge current to fully drop down to 0.08A (which is the phone's operating current, not charge current). The takeaways here are that:
1. The phone's charge time calculation is WAY off.
2. Even at 100% the phone is far from truly being in CV mode thus is truly far away from being fully charged
3. I suspect ONE of the reasons some people are having poor battery runtime is because they think they are starting fully charged when they aren't
Li-ion and li-pol batteries do not need a period to "break in", and you shouldn't charge them over night, or even let them discharge fully
. That's what "they" say, but it clearly isn't true that they don't have a break-in period, they do. I've seen it on every battery powered device I ever had. Aside from the chemistry aspect many devices have a fuel gage that "learns" about battery capacity after a couple of charge/discharge cycles and frequently the very early estimates are wrong until it has had time to learn (making it appear the battery is "breaking in"). For this reason I always periodically run my batteries "into the ground" so that the fuel gage gets to see what the battery's present capacity really is. When I started the test above I started with the battery so discharged the phone refused to turn on. This poor initial estimate/learning not complete may be part of the issue I've outlined above