My phone switched off randomly and won't turn on?

[AC Question]

I was using my phone earlier (Huawei P8 Lite) and it just switched off. It had around 30% battery but I thought maybe I just hadn't noticed it running out. I've tried to switch it back on and there's no light or vibration, and I've now left it on charge for 5 hours and still nothing. No charging light or anything. The phone is only 2 months old so what should I do?

 

[VidJunky]

I'm pretty sure this is the model that I've seen a similar issue with the battery indicator not reading correctly, or making big jumps from like 30 to 5 unexpectedly. Anyway if you're sure the charging cable is good leave it charge for some time, which it sounds like you did. Then unplug it and put it back on the charger. When the phone died for lack of charge it sometimes won't show a charging indicator and the screen won't always come on with the charging symbol so no need to panic yet. If after the second round of trying to charge it won't power up you may consider taking it in to your provider's repair dept. Two things tho onebe sure your charging cable is good and two be patient. These devices don't like being shutdown due to low battery so, and if I'm correct that this is the model, you think the battery level indicator seems high for the amount of usage you've had that day plug it in even if for just a second to confirm the battery level. You may, but probably won't have to hold the power button a little longer than expected attempting to power it up.

 

[Rukbat]

First, 30% is FAR loo low to drag a battery down to. You should charge it at 50%. Allowing it to run down to 40% won't shorten the life that much. After that, it can. (It might also lead to dendrites - which mean a new battery - but the jury is still out on that one. And it's a HUGE jury - the automotive industry.)

Second, an unexpected drop from 30% to 5% is almost always a small dendrite (which, again, means replacing the battery).

What it sounds like is that the phone ran down past the precharge point - which means that the phone's internal charging circuitry can't charge it. Since the battery can't be removed (there are external chargers that can revive almost "not there any more" batteries), it has to go to a repair shop.

In the future - for anything using a lithium battery (lithium batteries are not deep-discharge batteries), start planning on recharging it as it drops to 50%. By the time you get to recharge it, it should be between 40% and 50% - which will keep it going for a long time.