what battery percent should we connect charger?

[Pars987]

Hi. I know we don't have to use the device while its charging and we should disconnect charger at 100% but a question :

what is the correct way of charging to avoid damage to device battery ?

for example when should we connect charger ? 10% ?    15% ?    30% ?   or ... ?

any Company like Sony say anything official about it ?

[Uliwooly]

You can charge your phone at any % and you can use your device while charging 

[Rak1tA]

If you recharge your phone from 50% to 100% - it will be more useful than the 20% to 100%. That is, the smaller the charge up to 100% better. Frequent recharging useful complete charge cycles. And when the battery is charged the phone itself will stop the charging process.

[Pars987]

Yes but i asked for a healthy & long battery life after months of usage , i saw news of fire and electricity shock of devices like iphone & others while they were on charging and used by users , i see devices myself that their battery are damaged when used on charging , especially in calls or games

for connecting a charger some say connect at 10-15% and some say connect at 20-30% is not having different just its important to get 100% and remove the charger at this percent , You know  Sony conference for Xperia XZ in Iran said its important to disconnect mobiles charger at 100% but they don't say anything about the percent of charger connecting for healty battery

[Pors]

15%