# Can 12v destroy a laptop instead of 11.1v

I am making some experiment on the 18650 battery, I learnt that their charging voltage is 4.2v while nominal voltage is 3.7v. I made a 2ways parallel connect of 3 serial connection just like the laptop battery pack, on the laptop 11.1v is written which is 3 x 3.7v but I charge the battery with a 12.5v charger which is still with the charging range of the cell 4.20v * 3=12.6 and the battery is now charge to 12.3v and started getting warm so I disconnected it even despite that its not yet up charge to my charger range. But the problem is that I dont know if 12.3v would damage the laptop if I connect to the battery port with the circuit since they wrote 11.1v, and i would like to know what that nominal voltage mean and I would to know maybe if I increase the battery cells from 6 to maybe 9 or 12 in other to increase the amp/h would it damage my battery. If would be very greatly for your help

• Wait, you connected a constant voltage supply directly to a lithium chemistry battery? Stop what you're doing right now before you hurt yourself or burn your house down. Feb 3, 2017 at 2:46
• Each cell in a 2P3S array must be balanced in ESR and mAh capacity within 2% for good performance. Reducing the charge voltage to 4.1 reduces heat loss which in turn extends life. Warm is OK if warm is 45'C . 60'C is excessive or limit if you dont mind shorter charge cycle life. Cut off is usually 10% to 20% of CC limit rating. Feb 3, 2017 at 2:49
• Current MUST be limited to some Imax during charging. This is typically either Imax mA = Battery mAh or Battery mAh/2 depending on the battery manufacturer's spec, Charging 3 x LiIon cells to 12V is OK as long as you remove Vcharge when the battery reaches 12V. The "proper": way to do this is more complex by removal WHEN V = 12V will work OK. Leaving a 3S LiIon battery connected to an ~= 12V source indefinitely is liable to damage or perhaps destroy it. Feb 3, 2017 at 6:30