Help how to calibrate/drain battery when phone keeps turning off at 0%

[catchingup]

What I mean is, I think my new phone battery still has some juice at 0%, but android is programmed to turn off when it hits 0%.

I can still turn on the phone, even though it says 0%, but android shuts it off right after it boots to home screen.

So how can you calibrate the battery to account for whatever small amount of juice is there after android says there's 0% ?

I tried to drain the battery, but it's impossible to drain beyond 0%.

I'm only doing this because my L90 has very lousy standby time.

 

[Fox Mulder]

That would be a built-in protection mechanism for the battery. Li-ion batteries are not intended to be discharged all the way to 0%, doing so can ruin them. So it's normal for the phone to shut off at some point before that happens, it may say 0 but there will still be a few % charge remaining.
If you are having problems with poor battery life this isn't the reason. You may be in a bad signal area which will increase battery drain, or there may be apps or processes running on the phone causing it. Check what apps and services are running, turn off any that are unnecessary. Disable any sync and push notification options that aren't really needed.
Your battery could also be bad, if you have a spare try it and see if it's any better.

 

[Crashdamage]

It's *very* bad for the battery to completely run it down to zero. To avoid that the charge control chip forces a shutdown before the battery is totally discharged, actually at about 3-5% regardless of what the meter might say. Battery meters ate not precise anyway. It's best for battery health to not let it get below 15-20%.

To find out the cause of poor standby time, charge it and let it sit uninterrupted for at least 8-10 hours. Them go to: Settings > Battery and see where the power is going.

Edit: Just got a ninja star inna back...